Seminar: Transport Safety ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 01i ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Using expert knowledge and rules for driver monitoring: an alternative approach BEKIARIS, E, Hellenic Institute of Transport, Greece BROUWER, R, TNO-TM, Netherlands JANSSEN, W, TNO-TM, Netherlands NIKOLAOU, S, Hellenic Institute of Transport, Greece WEWERINKE, P, TNO-TM, Netherlands Introduction Driver hypovigilance (‘falling asleep at the wheel’) is a major cause of road accidents, accounting for up to 20% of serious accidents on motorways and monotonous roads in Great Britain, whereas 56,000 crashes are stated by the US police annually, having as primary cause the driver hypovigilance, according to NHTSA studies. The European Commission Road Safety strategy identifies driver hypovigilance as an important factor in road fatalities and supports the application of driver monitoring systems to achieve its goal to reduce road fatalities by 50% by the year 2010. AWAKE is a European project, co-funded by the European Commission under the IST initiative of the 5th Framework programme. The objective of AWAKE is to increase traffic safety by reducing the number and the consequences of traffic accidents caused by driver hypovigilance. In order to achieve this objective, AWAKE intends to develop an unobtrusive, reliable system, which will monitor the driver and the environment and will detect in real time hypovigilance, based on multiple parameters. In order to enhance the reliability of the detection system, AWAKE uses both a stochastic Hypovigilance Diagnosis Module (HDM) and a deterministic filter (DHDM). More specifically, in parallel to the stochastic approach followed by HDM development, and based on results of previous studies and projects, both absolute and relative criteria will be defined to be fed into an expert knowledge system, in an attempt to filter the sensor data input to HDM, as well as to develop a deterministic type of HDM (DHDM), as a fall-back position. This minimal HDM will be compared also to the overall stochastic HDM in terms of efficiency, computation time, etc. This paper deals with the design of the deterministic hypovigilance diagnosis module, the expert tools and rules to be used within it, as well as on the use cases definition. System Design The Deterministic Hypovigilance Detection Module (DHDM) has the following specifications: • A simple (deterministic) system (DHDM) that predicts the vigilance state based on a given set of sensor measurements, such that driver’s hypovigilance can be diagnosed. • Potentially, the DHDM must be robust (adaptive) with respect to inter-subject variability (adjusted to specific driver), intra-subject variability (adjusted to specific

driver state) and specific traffic conditions (hypovigilance must be predicted for all

specified traffic conditions). • The DHDM must have a diagnostic performance level comparable to the (stochastic) HDM. The trade-off between system simplicity and diagnostic performance is a key

issue to be investigated. System components DHDM consists of the following components: • Sensor data (measurements); • Derived measures; • Integration of measures (data fusion); • Hypovigilance state criteria; • Diagnosis of hypovigilance.

Sensor data The selected sensors for the DHDM are: eyelid closure, hand pressure on steering wheel, steering wheel movement, lateral vehicle position, front obstacle distance, TTC (Time To Collision) and TLC (Time to Line Crossing) and emerge also widely in literature. Other measures in the category of psychophysiological measures are: EEG, heart rate, GSR, EMG, etc., and in the category of task performance measures, such as rate of turn and driving speed. Derived measures The foregoing raw sensor data (whether or not filtered, etc.) have to be processed in order to be useful as indicators of the corresponding notion. For example, the measurement of eyelid closure can be related to loss (or a reduced state) of alertness if the derived measure indicates that the eyes are closed for some time. The most well known derived measure in literature is the PERCLOS measure, which is defined as (typically) at least 80 % of the time that the eyelid is closed. This reflects a sustained (slow) eyelid closure rather than a blink. Another example is the steering wheel movement. In order to reflect an increase in driver drowsiness, the derived measure should reflect a deviation of “normal” driving, e.g. in terms of a minimum or a maximum amount of control activity, e.g. in terms of the standard deviation of the steering wheel angle. Finally, the lateral vehicle position can be related to degraded driving performance due to hypovigilance, in terms of a given lane exceeding, or in terms of a given standard deviation of the lateral position, etc. Integration of measures There is a general agreement that more than one of the foregoing measures should be used to obtain a reliable detection of hypovigilance. Typically, one or more driver behavioural measures (e.g. slow eyelid closure, handgrip pressure and EEG) are combined with task performance measures (e.g. steering wheel movement, lateral acceleration and lateral position). This integration of the various measures can be based

on a variety of algorithms. In Wierwille et al. 120 different algorithms were tested. The best prediction results to be implemented in algorithms were in fact obtained by using 4 to 7 different variables together. Another simple way to combine various measures is to consider these different measures as follows: each measure is tested against some criterion value (to be discussed in the following) and the decision that hypovigilance has been occurred is made if all the separate measures have exceeded the corresponding criterion value. This approach is indicated within this study as an ‘engineering’ approach. More practical is the use of a Neural Network to combine the various measures as inputs to a network, resulting in a prediction of hypovigilance. This approach will is also analysed in this study and is compared with the ‘engineering’ one. Hypovigilance state criteria Given the information of the separate or combined measures, it is the question how this information can be used to decide about hypovigilance. For example, the standard deviation of the lateral position exceeding a certain value possibly reflects an incipient hypovigilance. However this value is varying per subject, but also depends on the specific traffic situation. Driver behavioural measures (e.g. EEG) also vary in time and therefore also the criterion value cannot be time-invariant. The goal of the present phase of this study is to design a deterministic hypovigilance detection system, which means that the effect of the traffic situation will not be considered. Diagnosis of hypovigilance Based on the (separate or combined) measures and the corresponding criterion value(s) the decision has to be made that the hypovigilance state has been occurred. The general issue of any decision is the decision performance in terms of the percentage of correct decisions (recognition rate) and the decision errors. The two types of errors are the miss and the false alarm. Typically, decision-making performance is specified in terms of the recognition rate and the false alarm rate. Conclusions Because no definitive (hypo)vigilance measure and specific sensor measurements were available, the design had to be tentatively and exploratory, i.e. based on a hypothetical vigilance ‘data’ and considering possible, alternative sensory inputs. Nevertheless, much insight could be obtained in the effect of a variety of system aspects (sensory inputs, signal processing characteristics, decision making aspects, etc.) on the hypovigilance prediction performance. In addition, a system design procedure could be developed that can be used for the definitive design process, based on the definitive measure of (hypo)vigilance and the selected sensory inputs, using the models and computer programs that are developed within this study. References

AWAKE (IST-2000-28062) Project, ‘Description of Work’, August 2001. Clark, J. and Yuille, A.L. (1990). Data fusion for sensory information processing systems. Kluwer Acad. Publishers. Dillies-Peltier, M. A. (1997). Driver vigilance decrease detection: A real-time, driver adaptive on-board system. Proc. of the 4th World Congress on Intelligent Transport Systems, Berlin, Germany. Hall, D. (1992). Mathematical techniques in multisensor data fusion. Boston Artech House. ITS ‘E-safety’ Lyon congress proceedings, ERTICO, September 2002. Kircher, A., Uddman, M. & Sandin, J. (2002). Vehicle control and drowsiness (VTI-Report). Martindale, C. (1992). Cognitive Psychology, A Neural-Network Approach, Brooks/Cole Publishing Company. NCSDR/NHTSA Expert Panel on driver fatigue and sleepiness, “Drowsy Driving and Automobile Crashes”, NCSDR/NHTSA report HS 808 707, 1998. Onken, R. & Feraric, J.P. (1997). Adaptation to the driver as part of a driver monitoring and warning system. Accid. Anal. And Prev., vol. 29, no.4, pp. 507-513. Pergamon. Russell, S.J. & Norvig, P. (1995). Artificial Intelligence – A Modern Approach. Prentice-Hall Inc., USA. Sánchez-Sinencio, E. & Lau, C. (1992). Artificial Neural Networks: Paradigms, Applications, and Hardware Implementations. IEEE Press. Simpson, P.K. (1990). Artificial Neural Systems: foundations, paradigms, applications and implementations. Pergamon Press, New York. The Royal Society for the prevention of accidents, ‘Driver fatigue and road accident: A literature review and position paper’, February 2001. Wewerinke P.H., Janssen W.H., Brouwer R.F.T., “DESIGN OF A SIMPLE HYPOVIGILANCE DIAGNOSTIC SYSTEM”, AWAKE project report, 2002. Wewerinke, P.H., Hogema, J.H. & Verschuren, R.M.A.F. (2001). Modelling lateral vehicle control to describe handling. TNO report, TM-01-D018. Wierwille, W.W. Ellsworth, L.A., Wreggit, S.S., Fairbanks, R.J. & Kim, C.L. (1994). Research on vehicle-based driver status/performance monitoring: Development, validation and refinement of algorithms for detection of driver drowsiness. NHTSA, Final report: DOT HS 808 247. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 01ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Driving under the influence of alcohol IN'T VELD, R, Ministry of Transport, AVV, Netherlands Since the nineteen-seventies, surveys were carried out to assess the alcohol consumption of car drivers. These studies had always been carried out by the Dutch Road Safety Institute (SWOV). From 1999, the governmental Transport Research Centre (AVV) has carried out these studies. By the early nineties, not only national trends in drink driving but also developments on the provincial level could be tracked, due to the rise in the number of random sobriety checks performed. Toward the latter part of that same decade, the random sample encompassed some 20,000 to 30,000 roadside checks, which made it possible to draw conclusions at the level of the majority of the 25 police districts as well.

In the Netherlands, the figures for driving while intoxicated fell in weekend nights from 4.6 % in 2000 to 4.2% in 2001. Due to the number of checks, this may be regarded as a significant reduction. A positive effect of stepping up enforcement is clearly noticeable. In 2001, the percentage of drivers under the influence of alcohol in districts where the special enforcement teams were put in place, was found to have declined that first year by 15%. The study in the previous year had led to a comparable conclusion. When the Enforcement teams will be national implemented, it may be expected that the percentage of drink drivers shrink the following year in the other regions as well. However, it was shown that this decline will subsequently taper off in the second year after stepping up enforcement. The figures over the last few years show, that the majority of drivers under the influence participating in traffic at night during weekends were found to have been visiting a licensed establishment of some kind. An additional 5% had just come from the canteen at their sports club. Relatively high percentages of offenders were found: • between 2.00 and 4.00 a.m. (Friday nights between 10 and 11% and Saturday nights round 8%); • among male drivers between the ages of 35 and 49 (6%); • within Amsterdam and some cities in the neighbourhood (6% and more).

Figures of accidents combined with the percentages of drink driving show that there is a much higher risk of getting involved in an accident while under the influence of alcohol. Young male car drivers (18-25-year-olds) are a special risk group. The quantity of alcohol consumed, combined with the small amount of driving experience, annually causes approximately 25% of all fatal alcohol-related accidents in the Netherlands. Therefore, a supplementary study was launched from 2002 in connection with the introduction of the beginners’ driving licence. In 2004, drivers with a Blood Alcohol Content (BAC) in the 0.2-0.5‰ range will be in violation of the law if they have held their drivers’ licence for less than five years. About 80 % of them are between 18 and 25 year old. In 2001, a total of 4.1% of young drivers had a BAC in the aforementioned range (0.2 – 0.5‰). 87 % of them are men. Furthermore, at the end of 2001, the “Bob” campaign has started in the Netherlands. In this campaign Bob is the one who does not drink and drives his (or her) friends home. With the use of figures of 2002, there will be investigated if there can be measured an effect on the percentage of drink driving. To find such an effect is uncertain, due to a lot of confounding factors, which can vary in the same period. However, the main factors that lead to changes in the percentage of drink drivers and their effects are approximately known from earlier studies.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 01iii ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Young drivers: the problem of sleep GUNAY, B, Transport & Road Assessment Centre, University of Ulster, UK WILSON, I, Transport & Road Assessment Centre, University of Ulster, UK WOODSIDE, A, Transport & Road Assessment Centre, University of Ulster, UK According to leading doctors and researchers the average human being requires at least eight hours sleep to provide for sixteen hours of sustained wakefulness. This project found that if people are deprived of much needed sleep at night they will become sleepy throughout the day and are more likely to fall asleep at inappropriate times. This has major implications for most of the population who drive and other road users. In NI whilst a low percentage of young people actually drive, their involvement in road traffic accidents and in particular, sleep-related accidents is substantial. This paper investigates the tendency of young drivers to fall asleep at the wheel and the many reasons causing their lack of sleep. Young people by their very nature (youth) should be fit, healthy and able to cope with life, but nowadays with emphasis put on socializing, fast/convenience food and the increasing car culture, many are overweight and spend less time sleeping adequately. This study highlights the possibility of deteriorated driving performance as a result of lack of sleep. Driver fatigue may be a contributing factor to one in five road traffic accidents and this is a potentially dangerous problem for road safety. Driving standards for most age ranges whilst lacking of much needed sleep deteriorated notably. This project found, however, that the effect of driving with age group 17-24 years old and indeed 25-34 years old deteriorated more significantly than any other age range. This age group (17-24) was therefore highlighted as a high-risk group. Surveys from the 17-24 year old age group showed that more males than females tended to be drowsy at inappropriate times. Sleep deprivation has the potential to affect all drivers, as not obtaining adequate sleep can be done without intend. For example, someone in a stressful high-powered job, who also have a family to care for? However, for the majority of the young driving population, this is not the case. The top priorities encountered by young people include, university, job (semi-skilled or lower), socialising and/or a part-time job. Lack of sleep is derived as a result of an over zealous social life (which is considered to be part of university life) running late with an assignment or working a weekend job. In Northern Ireland people under the age of 25 comprise 37% of the country’s overall population. Of this 37% approximately one quarter of them are of legal driving age (17 ages +). According to Police Service of NI and Department of Environment data, young car drivers (17-25) form a lesser percentage of NI car drivers, however they are attributable for a sizeable amount of fatal and serious road traffic injury accidents. Young male car drivers total 6.9% of all NI car drivers, but are attributable for 27.4% of all fatal and serious injury accidents. Young female car drivers form 5.5% of all NI car

drivers and account for 6.7% of injurious accidents. It is clear that of all age groups of drivers, it is the young drivers that are contributing to more road traffic accidents that any other age group. The investigation also noted that people, who tend to be ‘dozy’ per se, were at more risk of being involved in a sleep-related accident that those who were of an ‘alert’ behaviour normally. It emphasises the risk of young drivers, particularly young male drivers and the danger to themselves and other as a result of lack of sleep. This research is beneficial as it proves that there is a definite link between drowsiness and driver performance and will therefore enable measures to be designed to eradicate the risk of road traffic accidents occurring as a result of drowsiness. Concluding Remarks Young people in society are the future, they need to learn from example but also to set example to the next generation of drivers. It is unfortunate that this study highlighted the problems that young drivers are causing for road safety. As adults they need to be made more aware and responsible for their actions. But as they make up the smallest age group of drivers but the largest in terms of accidents; their responsibility must be questioned. This paper concludes that young drivers are a danger to the society in which they live as a result of their daily behaviour and lifestyle. Young males are in general ‘high risk’ in NI, this is somewhat confirmed in relation to total number of accidents that they cause or contribute to. One well-known principal causation being speed, but with an increasing number of incidents attributable to driver fatigue, it is stressing lack of sleep as a major contentious issue for the new century as we constantly push forward a 24/7 hour society. Recommendations Awareness is a more successful key to reduce these types of accidents. Detection is very difficult for police officers as there are no mechanisms available to them for identify sleep deprivation. Educating drivers through a range of mediums would be more beneficial than many in-car technology systems (as these often detect sleepiness when it is too late and the driver does not need to be asleep to be involved in a sleep-related accident). Keywords: Accidents; driver performance; sleep deprivation; young drivers ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 02i ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Incentive system for road safety in road haulage DEVILLERS, E, ECORYS, Netherlands JORNA, R, Diepens en Okkema, Netherlands PRUMMEL, G-J, Ministry of Transport, Netherlands SMIT, G, ECORYS, Netherlands 1. Introduction This abstract presents a brief outline of the project Incentive System for Road Safety in

Road Haulage by addressing the key issue of the project, the background of the project and the scope, the planning and the results of the project. The full paper will provide results from previous research in the field of the incentive system in the Netherlands (2001-now), results of a parallel study called Safety Culture (ongoing) where relevant and the results of the pilot studies (current project, ongoing). 2. Key issue of the project The road haulage sector is relatively often involved in road accidents. Instead of (more traditional) measures aimed at improving the infrastructure, the vehicle or the capacity of the driver, this projects aims to introduce a safety culture in road haulage companies by providing certain incentives to road haulage companies. These incentives are to be created by the manager of the road infrastructure (road managers), e.g. access to dedicated infrastructure, and are aimed at improving the accessibility of the road haulage sector. A trade-off is sought between incentives to the road haulage sector (accessibility) and improved road safety through road haulers that have incorporated safety culture in their organizations. The Dutch Ministry of Transport, Directorate for Freight Transport has initiated research in the field of incentive systems two years ago and is now in the process of starting pilot studies. The first phase of research was aimed at making an inventory of potential incentives that a road manager can offer to the road haulage sector. This phase was completed in 2001. Currently, the philosophy of the incentive system is piloted in five regions in the Netherlands. By the end of the year pilot results will become available and may result in steps towards a nationwide incentive system. A parallel process of research aimed at establishing insight in safety culture was started and is still ongoing. 3. Background of the project Road haulage is responsible for substantial amount of traffic casualties in the Netherlands; in 28 percent of the traffic deaths and 19 percent of the traffic injuries (being heavy ‘hospital’ injuries), a truck or delivery van is involved. Especially the injuries involving delivery vans are expected to grow the coming years. Almost 50 percent of all haulage related casualties occur on municipal roads. The project Incentive System for Road Safety in Road Haulage focuses on these haulage related casualties on municipal roads. The aim of Incentive System is to reduce the amount of traffic casualties by focusing on the human factor and road haulage companies involved. The Incentive System tries to stimulate an awareness of traffic safety in the entire flow of goods, thus leading to measures in the entire traffic system, i.e. introduce safety culture in the companies. The Incentive System aims at realizing an interaction between the regional road manager and the transportation sector (shippers and transporters). The interaction consists of a trade between the road manager who offers positive incentives and the transporters who provides a good quality transport product. For example a road manager can allow the transporters to use dedicated infrastructure, such as bus-lanes. In return the transporter has to incorporate safety culture in its organisation. The essence of the Incentive System is to create advantages for all parties involved; • road managers: safer road network

• transporters: better accessibility, leading to a better competitive position • shippers: more reliable logistic processes (more reliable deliveries)

In order to start the mechanism and to keep it moving, a dialogue between the parties involved was started and is ongoing. The first steps, including an inventory of incentives and a seminar on the incentive system in road haulage, have been taken and the response has been mostly positive. Some possible bottlenecks, such as enforcement, legal aspects and acceptation in the transport sector were already brought up at an early stage. The pilot studies in the Dutch regions will provide insight in what kind of incentives are suitable and what kind of bottlenecks have to be overcome. 4. Scope, planning and results of the project 4.1 Scope Momentarily preparations for regional pilot studies are taken. In some Dutch regions road managers, shippers and transporters are brought together. The aim is to identify regional problems and possible incentives to stimulate and valuate safe behaviour. Previous studies give examples of incentives that can be taken by both the road managers and the transporters, but each region will select itsown incentives. During the pilot study all kinds of indicators are monitored from which lessons can be learned. The insight in opportunities and bottlenecks derived from the pilots is important for the introduction of a nationwide Incentive System. 4.2 Planning The pilot preparation phase started in January 2003 and will be completed by April 2003. In the period May-November the pilots will be executed. First results will therefore be available at the time the full written paper is due. 4.3 Results The project will provide the results of the five pilot regions aimed at establishing an Incentive System, including the kind of incentive that was selected in order to improve accessibility, the way safety culture was incorporated in the road haulage companies, the kind of bottlenecks that had to be overcome and the way all parties have contributed. By synthesising the results of the five pilot regions (which are selected to provide a geographical balance) steps towards creating a nationwide system can be taken. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 02ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Road traffic safety: effectiveness of the European regulatory framework ELBURG, J C van, NEA, Netherlands

Introduction A truck crossing the Dutch-Belgian Border can do so without stopping because of the European internal market. For traffic safety reasons the driver behind the steering wheel is subject of European rules regarding maximum driving hours. However if the driver is stopped and appears to be behind the steering wheel for 24hours in a row he will face completely different sanctions on both sides of the border. The willingness to increase effectiveness of the rules set out has obviously not yet led to

harmonization of enforcement procedures in Europe. Moreover this problem will gain weight with the accession of Central and Eastern European (CEE) countries. Already now it is well known that some truck drivers/operators prefer to run the risks of the low penalties in CEE countries as the profits resulting from not taking the necessary breaks outweigh by far the costs of eventual penalties. This paper will set out the shortcomings and possibilities of traffic safety rules and their enforcement in Europe. Both for passenger and freight transport by road. The paper will do so by tuning in on the things that do not run effectively. However also by looking more closely at individual countries that have implemented a successful set of rules with complementary enforcement methods. The paper will take primary a policy/legal/institutional angle and not so much a technical. At the same time the paper will highlight practical and successful initiatives that where taken in various places in Europe to fight unsafe driving. The main objective of this paper is to analyze existing and potential of EU road safety rules, compare national rules as being applied in Member States and tune in on the control and enforcement process. Conclusions and recommendations will address both the EU and national authorities. Background The White Paper on European transport policy for 2020 “ time to decide” has chosen to launch a high profile ambition regarding traffic safety: halving the number of deaths caused by road accidents until the year 2010 (reference: 2000; 40.000 people killed) The paper especially intends to conclude to what extent and under which circumstances the high profile ambitions are realistic. Road safety is a major concern on the political agenda of the European Union. According to the White Paper the EU intends to join forces with the national and local authorities to reduce the number of road accident victims e.g. by the harmonization of penalties among the Member States. Prior to that objective it is necessary to know the dissimilarities in the traffic rules themselves to ensure that enforcement is fair and effective (see introduction). There is a general agreement among countries regarding the main road safety problems. A wide variety of solutions have been put in place and further measures are being developed. Countries seem willing to learn from each other and use best practices (Scandinavia, Netherlands, UK) as a benchmark. Still when it comes down to the adoption of standards in real life (e.g. standards for maximum use of alcohol) a lot of constraints arise that apparently have nothing to do with the road safety objectives. One of the key administrative problems is Europe is the application of the principle of subsidiarity. On the one hand the Commission issues high level ambitions as shown. On the other hand the Commission acknowledges that the responsibility to take measures here is mainly through national and regional authorities (one can wonder therefore the value of the “time to decide” objective if this is not translated into national goals). The role the EU can play (according to the European Commission), apart from issuing legislation is:

• Facilitate exchange of good practices • Harmonization of penalties • Promotion of new technologies

The paper will analyze the value of these actions. Exchange of good practice is always useful. The Commission for example refers to the Swedish ‘zero deaths’ plan. The plan addresses all areas in which local authorities and companies can play a leading role. However without drawing conclusions at this stage it seems to be unlikely that a large contribution in terms of improved traffic safety should be expected from exchange of know how. Harmonization of penalties is an extremely difficult subject. It makes sense that the driver referred to earlier – behind the steering wheel for 24 hours in a row – faces similar severe consequences no matter on what side of the border he operates. However Member States are extremely keen on their own competencies regarding penal law. Results can be expected here only very gradually. Regarding the promotion of new technologies the Commission remains rather vague on what is meant here (at least in the White Paper). This is noteworthy as much European and national research is conducted in order to invent measures to increase traffic safety. Particularly in this field the European Commission should be able to initiate European co-operation and make sure that research in this field results in more then the sum of what individual Member States have to offer via the joining of forces. Finally This paper will take a critical view on EU traffic safety policy and the way it interacts with national (and local) competencies. Apart from a juridical analysis this paper will bring forward practical examples of successful practices. This paper will be based upon amongst others an European Commission funded study concerning ‘road traffic rules’ that will run in 2003. The 2003 study that has the objective to identify the most effective traffic safety measures and enforcement methods in Europe and should come up with recommendations to implement these strategies elsewhere, either on the European, national or local administrative level. Naturally also other relevant research and policy papers will also be used. Although the primary objective of the paper is to present successful regulatory initiatives to fight for less accidents on the road also the issue of competencies of administrations and subsidiarity is touched. What rules should be set out on which administrative level? How about the lack of harmonization of enforcement standards for European rules (see example in the introduction). It is obvious that all authority levels have a role to play to increase traffic safety. The question is however what role. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 03i ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Enforcement of speed limits in Norway - actual policy and driver's knowledge JORGENSEN, F, Bodø Graduate School of Business, Norway

The paper deals with two issues: First, it shows the development in the number of speeding offences in Norway and their seriousness.Thereafter it reviews the development in the penalty rules for speeding offences and the probablities of being caught speeding on different streches of road. These figures are compared with the resources used on speed controls in order to infer the development in the productivity of such controls. Special attention is here offered to discussing appropriate productivity measures as far as speeding controls are concerned. The rest of the paper is concerned with reviewing Nowegian drivers' perceived values on the penalties for speeding and on the probablity of being caught speeding. These values are based on personal interviews with a sample of 210 Norwegian drivers who stopped at a petrol station. Besides asking them about their perceived values on the magnitudes of the penalty for different speeding offences and the probablity of being caught speeding, they were asked a range of personal questions such as age , driving experience etc. Using regression analysis the paper analyses how drivers' knowledge about speeding enforcement rules are related to their personal characteristics. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 03ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Optimal social speed limits in a highway: suitability of the 120 km/h speed limit in Barcelona

LOPEZ-PITA, A, Universitat Politecnica de Catalunya, Spain ROBUSTE, F, Universitat Politecnica de Catalunya, Spain VELEZ, M, Universitat Politecnica de Catalunya, Spain This article is intended as a small contribution in the study of the thorny problem of road safety, scientifically questioning the existing maximum speed limit on highways where the road layout, vehicle power, physical environment and driver ability permit high driving speeds. Speed limits in Spain are the most commonly ignored driving rules. When a rule is not respected by almost anyone, its enforcement is difficult since it would mean giving tickets to everyone. In a mature society, that fact points out that perhaps the people do not perceive the rule as “valid”. The question which arises is: if 120 km/h is not perceived by people as the “right” speed limit, what should it be? This paper presents a methodology used to determine the “optimal” speed in a highway that has a physical layout to permit high driving speeds. “Optimal” speed is defined as the speed presenting the least social costs. To determine the optimal speed, it has first been necessary to perform a socio-economic analysis of factors which vary according to speed. The factors studied are: time savings, comfort – driver preference, accident rate and environmental impact. For each of the factors, ad hoc models are calibrated. Of course, the main deterrent to higher speeds (besides the highway physical layout) is the social cost (and alarm) of accidents: high speeds increase the variability range of car speeds, hence the standard deviation of the speed and thus they increase the probability of accidents, growing both in number and fatal outcome. Through use of the standard engineering practice of assigning monetary values to loss of life, injuries and crashes, we

are able to insert traffic safety as an important factor, but it remains just one more factor of the global decision. A specific traffic safety study has been performed for the selected stretch of the highway. The numerical application has been performed on the A-7 highway in Barcelona, Spain. A segment of this highway one hour’s drive north of Barcelona was chosen for its straight layout and little agitation traffic. The model yields a result of 124 km/h as the optimal social speed (currently, the average speed in that section of the highway is 134 km/h). The conclusion is that in the analyzed stretch of the A-7 highway, current speed limits could be increased to 140 km/h if these new speed limits were really enforced. The paper also comments on the generalized speed limit violation in Spain. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 05i ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Child pedestrian traffic exposure and road behaviour HARVEY, H, Environmental Health Protection and Safety Centre, UK VAGANAY, M, Transport and Road Assessment Centre, UK WOODSIDE, A R, Transport and Road Assessment Centre, UK Over the past twenty years progress has been made in reducing the number of road deaths and traffic accidents. However the number road casualties is still very high amongst some groups of vulnerable road users such as children and represent a real threat for children’s health. Traffic injuries are the leading cause of severe childhood injuries in developed countries. In 2001, 1 983 children were killed or seriously injured in France (3.4 per 100 000 population), 4 986 in Great Britain (8.5 per 100 000 population), and 238 in Northern Ireland (14.1 per 100 000 population). After motor-vehicle-occupant injuries, pedestrian injuries are the second cause of road casualties for children. Great Britain has one of the worst child pedestrian fatality rates in Europe (in 2000; 0.15 per 100 000 population) and in comparison to England, Scotland and Wales, Northern Ireland produces the worst child pedestrian fatality statistics (0.59 per 100 000 population). France despite very high road death rates, have much better records concerning children with almost 4 times less children pedestrians killed (0.15 per 100 000 population) than in Northern Ireland. The major aim of this investigation is to seek causal explanations for the differences in child pedestrian casualties in France, Great Britain, and Northern Ireland. It would helped to identify risks factors associated with child pedestrian accidents in these countries and to undertake preventive measures that may be more soundly based. A child’s risk for pedestrian injury is usually related to his overall exposure to traffic. Different child exposure to roads might be a reason for differences in the child pedestrian rates. Previous studies suggested that road behaviour might be another explanation for differences between accidents rates. Therefore it is reasonable to evaluate and compare child exposure and behaviour of children in the road environment in each of these countries. Existing information on the traffic exposure and behaviour of children was considered unsuitable for a comparative analysis.

This paper describes a study that evaluates and compares the different road environment exposures and the road traffic behaviour of school children (5 to 15 year old) in Northern Ireland, Great Britain, and France. The results of this study will identifies the factors that may explain the higher accidents rates in Great Britain and Northern Ireland. This study uses a cross sectional survey incorporating questionnaires which were sent to primary school and secondary school to be completed by pupils. Particular attention was given to minimise the extent of bias in the sampling process with respect to socio-economic group, the type and density of children population since these factors have been linked in previous research to be linked with the variation of child accident rates. Quotas based on gender, age, social class and ethnicity were set to ensure that the profile of respondents in each area reflected the profile of all children in that area (urban, suburban, and rural) and that the profile of respondents in the designed areas reflected the profile of all children in the respective country. The findings indicate that the amount of traffic exposure (time spent near roads, number of road cross) of children increase with age but show little differences between boys and girls. Children from the lowest socio-economical group tend to spend more time near roads (walking or playing) than other children. Older children were less likely to be accompanied by parents however this less obvious for girls than for boys. Children are rarely allowed to walk or play near road after twilight and spent more time playing outside and near a road during summer months than winter months. Child road behaviour appears to be safer as they grow older. This might explain lower pedestrian casualties rates for older children (11 to 15 years old) than for younger children (5 to 8 years old) despite a higher quantity of traffic exposure. It seems that there is only little difference in the amount of exposure between children in the three different countries. However differences in the quality of exposure (type of roads and environment) might be one explanation for the differences in child pedestrian casualties rates. Another possibility for the differences in casualties’ rates may be attributable to differences by children with regards to their road behaviour. French children seemed to be exposed to a more dangerous environment however they seemed to be able to cope better in this environment. This research concludes with the study of preschool children (0 to 4/5 year old) traffic exposure and road behaviour. However due to the nature of the population (children under 5) a different method was used. Children of that age were not able to answer the questionnaires. Thus an interview-style questionnaire was addressed to the parents of nursery school children and preschool children (0 to 4/5 years old). The results of this study enable a better understanding of child pedestrian traffic exposure and behaviour. It also provides useful information for the development of a road safety strategy aimed at reducing child pedestrian casualties in Northern Ireland. Finally the research provides a useful basis to the other countries included in the comparison for the governmental road safety policy. KEYWORDS: child accidents, child pedestrian, traffic exposure, road behaviour. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Session TS 05ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Traffic satefy related attitudes with secondary school pupils and their accident involvement

KATTELER, H, ITS, Nijmegen University, Netherlands VERMEULEN, W, AVV, Ministry of Transport, Netherlands WOLDRINGH, C, ITS, Nijmegen University, Netherlands This paper describes the results of an in-depth study under the combined authority of the Dutch Ministries of Education and Transport to investigate knowledge, behaviour and attitudes towards traffic safety among pupils in secondary school age. The study was initiated in the context of a policy to further guide the development of traffic safety education. Traffic safety was unfolded in seven domains. Almost 1.700 pupils from all types of schools in the Netherlands were included in the study. An additional feature of the study was the measurement of pupils’ actual unsafe behaviour in terms of accident involvement. This provided empirical evidence for the link between attitudes and accident involvement. The study shows that specific attitudes correlate strongly to accident involvement.

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The new approach and the new approach quality scheme WRAMBORG, P, Swedish National Road Administration, Sweden The question what is worth aiming at in the field of traffic planning and street design has change from time to time. In the middle of the 1900th century most countries in Europe decided for the speed limit of 50 km/h in built-up areas, and more or less 50 km/h everywhere in built-up areas. But soon after was introduced the Pedestrian Street, with a speed limit of walking speed, and the Residential Street with a speed limit of 30 km/h. To underlie the social aspects of traffic planning a new street type was introduced in the late 1970th, the Woonerf. About at the same time measures were being made in the main streets to slow down the speed of the car traffic, especially in connection with pedestrian and cycle crossings. Later this new type of street was called 50/30-street, when passing pedestrian and cycle crossing motor vehicles should not drive faster then 30 km/h. Under the 1990th the ethical perspective in traffic planning arouse, Vision Zero and a much more consideration to the need and desire of children, elderly and disable persons are the most evident examples. In Sweden these new thoughts were put together in a new system of street types, called Målbild, in English The New Approach, also noticed in other countries, in France it is called La Nouvelle Approche. The New Approach is also presented in the European Union project Promising, sometime it is there called Wramstad. The Swedish government and parliament takes to the new ideas and urge on the development. The government and parliament summarize the new ideas in important decisions in 1997 and 2001. The New Approach is a try to transform the decision from 1997 into the field of urban planning, road network and street design. The principles of the Good example project is a try to transform the decision from 1997 and 2001 into the field of street design.

Good examples should reflect the goals of the transport political decisions. Good examples shall also be a good balance between the important urban qualities road safety, accessibility for all and a good environment including sustainability. The more precise meaning of what is now mentioned is developed in The New Approach Quality Scheeme attached. This Quality Scheeme is an expression for how The Swedish National Administration (SNRA) has tried to make concrete the decisions of the government and parliament and the instruction from the traffic department to the SNRA In The Quality Scheeme every urban quality has a number of sub urban qualities. For examples under the urban quality road safety you will find the concept pedestrian and cyclist crossing. To have good safety for a pedestrian and cyclist crossing (PCC) the motor vehicles must pass the PCC not faster than 30 km/ h (green standard), between 30 and 40 you will have less god safety (yellow standard), and if the motor vehicles pass the PCC at a speed of more than 40 the safety is low (red standard). Similar for the remaining urban qualities. The New Approach Quality Scheeme has been developed at the head office of the Swedish National Road Administration, in cooperation with the regions of the SNRA, and after having consulted The Association of Local Authorities in Sweden. References The New Approach Quality Scheeme Promising, European Union project, pages 59-63 in the final report, and pages 19-34 in work package 2 report. www.swov.nl english search promising 2001 The New Approach to Urban Planning, Road Network and Street Design, - Growth, Account, Implementation. Proceedings Conference Traffic Safety on Three Continents. 2001-09-15. Moscow, Russia. La Nouvelle Approche en matière d’urbanisme, de réseau de voies et de conception des rues. Proceedings Institut de l´Economie Urbaine. Séminaire « Deplacements et mobilité en ville: Qualité de vie et sécurité des personnes » (City Travelling and Accessibility). 2000-12-15. Paris, France. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 06ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Land use, transport and sustainable traffic safety BEEK, P van, Goudappel Coffeng, Netherlands SCHREUDERS, M, Goudappel Coffeng, Netherlands WEE, B van, Delft University of Technology, Netherlands The paper on which this abstract is based, focuses on the relationship between urban planning and traffic safety. In the Netherlands this topic is much debated, forms a part of the official policy but is nog often analysed. The background of the studie described, is formed by the so called ‘mobiliteitstoets’, an instrument that can be used by urban

planners and traffic and transportation experts in developing new areas. The instrument itself does not exist yet, but will be in the near future. The paper will describe the study that was implemented to make the first step in developing this instrument: the ‘mobiliteitstoets’. First, the Dutch policy on the issues of urban planning and sustainable traffic safety is concisely described. After that the backgrounds, new research and results are presented. The paper will end with the most important conclusions and recommendations. This abstract provides a brief overview of these topics that will be elaborated on in the definite paper. 1.1 The problem In the Netherlands trendstudies on traffic safety indicate a decrease in traffic deaths and victims. Especially when we look at longterm trends from the early 1970’s until today. The question is: if that is true, why is so much attention being paid to traffic safety? The most important argumentaion is undoubtedly the personal suffering and harm that traffic accidents entail. In this view, every traffic death or victim is one too many. Currently, the Netherlands are faced with over one thousand deaths and more than twenty thousand victims all caused by traffic accidents. Above that, the monetary costs of traffic accidents with which our society is confronted, are considerably high: estimations rank as high as 8 billion Euro’s each year. That amount is a lot higher than the costs of congestion. This is why we can refer to traffic safety as a very important social problem. 1.2 Policy background: what does the government wish for? Due to this previously (brief) described problem the Dutch Ministery of Transport, Public Works and Water Management. The quantitative goals for the years of 1998 until 2010 are: • a reduction in the amount of traffic (road) deaths with at least 30% (in 2010 750 each

year); • a reduction in the amount of traffic (road) victims with at least 25% (in 2010 14.000 each year).

If and when these objectives are met, as a result, societal gains can be expected as well: up to almost 4 billion Euro’s each year. 1.3 A solution? In the last thirty years, the Dutch government has had a lot of interest in all kinds of implementations that might (and did) improve the traffic safety in the Netherlands. Since the early 90’s this attention has been merely focused on the ‘triangle’: human, vehicle and road. The forthcoming paper will be focused on the impact urban planning might have on traffic safety. On of the more recent ideas is that in order to continuously improve traffic safety by integrating urban planning and traffic issues as early as possible in planningprocedures and urban developed processes. Due to this it will be much better possible to develop new, safe infrastructure as well as the environmental surrounding area. Expensive policy measures are expected to be unnecessary. In order to make this possible the future instrument ‘the mobiliteitstoets’ will include traffic safety as one of the basic criteria. 1.4 Research The paper will set out the most important results of a study called ‘One step up to the

mobiliteitstoets: urban planning related to traffic safety’. In the Netherlands a lot of knowledge is already availble on the relationship between urban planning ans mobility on the one hand and about the relationship between urban planning and liveable surroundings and the environment on the other. However, on the relationship between urban planning and traffic safety less empirical derived knowledge and insights are known. For this reason this particular relationship has been the focus of the study mentioned above. Above that, in the Netherlands there is a strong need for understanding the way in which urban planners take traffic safety into account in their current urban plans, which problems the encounter while trying to integrate traffic safety into their designs as well as about the instruments they have a need for to solve these problems. 1.5 Urban planning and traffic safety The integration between policy on urban planning and traffic and transportation has been on the Dutch agenda for years and a day. The most important objective has always been to integrate issues of traffic and transportation in the preparation, development and design of regional and local urban plans. Usually however, it became clear that this type of integration was almost never met in practice. In order to recover the backgrounds of this failure several studies have been performed in the past. Ons of the most outstanding conclusions based on these studies is that urban plans of newly developed locations still have a precedence over integration between traffic and transportationaspects and urban planning.Also, it is concluded that cooperation and communication between urban planners and traffic (safety) experts often fails to succeed. And if they cooperate well, than most often this happens only after the most important decisions in the design have already been made and it is (almost) not possible to implement any changes. Usually this means that when traffic and transportation issues are indeed taken into account this mostly happens after the important decisions have been made and the supposed integration can not be referred to as optimal at all. It seems that despite all the effort of traffic safety engineers and experts on urban planning and policy makers are unable to arrive at an urban plan that meets the requirements of balance between traffic, safety and urban development. What possibilities rest us in order to finally reach this objective of integration? 1.6 The ‘mobiliteitstoets’ Looking more closely at results from previously performed studies, the need is revealed for an instrument or a means that is able to create a better connection between traffic and transportation policy in general, and specifically traffic safety, with urban planning polict, during the planning, designing and developing process of newly developed as well as the redevelopment of existing locations. This needs to be an instrument that will let us develop optimal solutions for traffic safety problems without compromising too much on other important issues such as energyuse, the environment, accessability as well as the ethical quality of our social environment. The question is: what instrument is this? 1.7 Objective The objective of the so called ‘mobiliteitstoets’ is to facilitate regional and local policymakers in taking traffic and transportation aspects into account while preparing and developing local and regional urban plans. This instrument can not be viewed as a new, independent instrument on top of existing means. On the contrary, the mobiliteitstoets will provide an overview of existing instruments as well as the connection between these seperate means. Also, the mobiliteitstoets needs to motivate local and regional policymakers to act in a more proactive matter while developing urban

plans. 1.8 Lay-out and content At this moment it is not completely clear in which lay-out and content the mobiliteitstoets will have. We expect this to be more clear early Spring this year. However, we do know that the mobiliteitstoets will be a kind of ‘toolbox’ that encompasses existing as well as future instrument on mobility and urban planning. As fas as the content of the mobiliteitstoets is concerned, the mobiliteitstoets should at least consist of a set criteria on the issues of traffic safety, accessibility, urban planning policy and the environment. In order to see to that that this instrument will indeed be used in practice it is very important that the content of the mobiliteitstoets meets the wishes of the planners and polocymakers that will use this instrument in the future. That is why the instrumentscriteria are applicable in the assesment of urban plans. 1.9 The first step in developing the ‘mobiliteitstoets The paper will describe the study that was implemented to make the first step in developing this instrument: the ‘mobiliteitstoets’. First a literaturestudy was performed. After that several face-to-face interviews where conducted among architects, urban planners, municipality policymakers and others. Together, these people have given us insight into the cohesion between urban planning and traffic safety, the most likely content, lay-out and requisites of the mobiliteitstoets as well as the necessary means. 1.10 A quick look at the most important results The results show that there are two different factors responsible for the succesfull integration between urban planning and traffic safety: traffic and transporation related content factors and process and organisational factors. Both types of factors are needed to develop urban plans: without content knowlegde about traffic safety and urban planning it is impossible to even make plans and without organisation and process it is impossible to integrate all issues together. In short, the most important process and organisationrelated aspects are: 1. Forming and assigning the members of projecteam; 2. The working method and procedures of the projectteam; 3. The assignment of a projectmanager. In short, the most important contentrelated aspects are: 1. A common, joint contentbased approach of the design; 2a. The locations’ choice: existing or a new area; 2b. Concentration or united deconcentration in close range of public transport facilities; 3. Functional combinations; 4. The urban plan as a recidence; 5. Trafficnetworks related to the functions in this area. In the paper these aspects will be looked at more closely.

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Crash against obstacles in urban areas: a real safety problem

TREVE, H, CERTU, France Road safety is one of the first aims of urban transport. Accidents with crash against obstacles are a real safety problem in France: they concern 1/3 of the fatal accidents in urban areas, with 900 killed a year. But whereas there are may studies and a large variety of solutions in rural areas, there is quite few informations on this problem in urban areas. The paper present results of the first study in France (and perhaps in Europe) on this specific subject and give some answer to the following questions: what is the dimension of the safety problem, which type of crash happen, where do they occurs, what are the most dangerous obstacles, which general recommendations are possible in an urban design? In urban areas,prevention of this type of accident by road design measures is difficult, because there are quite a lot of objects needed by the city life and which can be bumped. It is impossible to put them away. Study present the French trial to treat this problem. The first solution remains an effective speed reduction; so that the crash severity is not too high. But in some cases, it should be completed by improvements, as new guards rails adapted to urban environment. It will also probably lead to use more and more breakable system , for example for lighting or signs poles. Those will be completed by an information for technical services in cities, to explain the problem and develop simple prevention measures. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 07ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

A wide-scale safety evaluation of traffic calming measures in residential areas GITELMAN, V, Transportation Research Institute, Israel HAKKERT, A-S, Transportation Research Institute, Israel In Israel, more than 70% of injury accidents and about a half of the fatal accidents occur in urban areas. Previous research indicated that, as to the location of road accidents in the town, there is a somewhat equal subdivision on those occurring on arterials, central city district and residential areas. Following this, the number of injury accidents in the residential areas throughout the country amounts to 5,000 per year, with 9,000 injuries involved. Due to a “scattering” pattern of accidents in residential areas and the high exposure of vulnerable road users on the residential streets, traffic calming is known as the best safety solution for such areas. Safety effects of traffic calming measures, stemming mostly from the reduced traveling speeds, were examined and proven in many countries, over the last two decades. Since the mid 80s, the residential areas established in Israel by the Ministry of Construction and Housing (MCH), were built with elements of traffic calming. Among the measures, which can be frequently found in the field today are: carriageway narrowings, street courts, various speed humps, roundabouts, etc. However, until recently, the effects of these traffic arrangements on the residential areas’ safety, has not been examined, neither on a macro scale of whole residential areas, nor on a micro scale of specific measures. The purpose of the study presented was to evaluate the safety benefits of traffic calming measures, applied on the streets of the MCH residential

areas. The evaluation of safety benefits was based on the estimation of travel speeds and the analysis of accidents that occurred at those residential areas, as opposed to control sites. The study comprised 37 residential areas situated in towns of Haifa and Galil counties, in the north of the country. For each residential area, a comprehensive set of characteristics was supplied, which included the location, the population size, the number of housing units, the motorisation level, the socio-economic level, the style of housing, types of streets, road characteristics, types of traffic calming measures and their density on the streets. The characteristics of housing, roads and traffic arrangements were provided based on the results of field surveys of more than 300 streets belonging to the residential areas. The speed survey was arranged on a representative sample of streets, for various measures (e.g. several forms of speed humps, raised pedestrian crossings, carriageway narrowing on one or both sides, street courts, rumble strips, physical separation on a curve, etc) and their combinations. The speed estimates (e.g. mean speeds, 85-percentiles) observed at the sites of treatment were compared with similar values attained for control sites (streets with no measures applied and streets from other typical residential areas). The findings demonstrated that all the measures considered, except for rumble devices, are effective in reducing speeds, both at a point and along a road section. The multitude and a combination of measures like street courts, dense speed humps and narrowings, was found to be the most effective treatment for traffic calming in the residential areas. To ascertain the effect of traffic calming treatment on travel speeds and safety in the residential areas, the levels of treatment were defined for the residential areas, depending on the scope and kinds of measures installed in each one. The travel speeds were found to be significantly lower in the residential areas with a “high” level of treatment as opposed to “medium” or “low” level. The accident analysis was based on two kinds of comparison with control-group sites: a – with safety levels of the towns where the MCH residential areas are situated; b – with the safety level of control sites (typical residential areas of similar size and socio-economic level but not established by the MCH). The findings showed that in most cases the safety level of the MCH residential areas was higher than for the towns; 63% of the residential areas suited the definition “safe”. However, comparing with the control residential areas, the evident safety benefit was observed only for the MCH residential areas with “medium” level of treatment, whereas for the MCH residential areas with “high” and “low” levels of treatment, the problem of pedestrian injury and the problem of severe injury remained; the safety benefit at those sites was seen only in the overall reduction of accidents. In general, the study findings support the traffic calming approach as a safety treatment applied on the scale of a residential area but also indicate that there is a great need in changing the current way of planning. In the process of residential area planning there should be a preliminary and strategic stage, which should determine the street functions within the residential area and, then, the preferable traffic calming measures for these streets. The study findings have also a range of practical implications concerning the efficiency of various calming measures in the context of their design.

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Customer attitudes towards and perceptions of telematics in cars KIDD, M, Accent Marketing & Research, UK SHELDON, R, Accent Marketing & Research, UK Business Background Telematics is an exciting, emerging technology within the automotive industry that encompasses the interactive exchange of information in-vehicle, either by voice or as data, over a wireless communications network. Telematics offers such applications as emergency and roadside assistance, notification of air bag deployment, navigation aids, remote door unlock, vehicle security notification and stolen vehicle tracking services. More advanced systems can provide individually customised services such as travel information, voice mail and email facilities, news updates and entertainment features. Although convinced of the enormous business potential of telematics, automotive manufacturers have been uncertain as to the precise content that end-users envisage, the service packages they most value and how much they are prepared to pay for the individual components of the telematics system. And in the absence of real business case examples, some telematics projects have been cancelled – as happened, for example, with the collaboration between Ford and software company Qualcomm. It was in this context that Frost & Sullivan commissioned Accent Marketing & Research to conduct independent market research among customers in the new car market to establish customer preferences for the telematics product. The research was managed by Mark Kidd and directed by Rob Sheldon. Objectives The main objective of the research was to establish customers’ preferences for the individual features of the telematics system and their willingness to pay for the individual and combined components. In addition, the research measured awareness and usage, customer opinions as to the quality of different offerings from different providers and their preferences for billing, position and display options. The Research Accent developed a programme of stated preference surveys, which were conducted in October and November 2002 among customers who had purchased a new car within the previous two years. The surveys comprised computer-aided telephone interviews,

each lasting about 30 minutes, and four hundred interviews were conducted, 100 each in the UK, France, Germany and Italy, using mother tongue speakers. Due to the complexity of the concepts being explored, a detailed information pack was posted to each recruited respondent prior to the main interview being conducted. The pack also contained one of four sets of stated preference exercises to which the respondent could refer during the interview. Segmentation was applied to the new cars, which were divided into four different price bands: • €12,000 to 17.999 • €18,000 to 22,499 • €22.500 to 26,999 • €27,000+.

The survey sought information on: • frequency of driving on different types of roads • awareness and use of different telematics features • priorities of different telematics features through three stated preference exercises • awareness and opinion of different service providers’ telematics services • billing and payment preferences of telematics services • desirability of different telematics services • usefulness of being able to source navigation directions to different types of points of interest • respondent characteristics.

Stated Preference Exercises The first stated preference exercise looked at those issues concerned with road safety and comprised four different attributes. The second exercise focused on information and entertainment and comprised three attributes. Finally, the third exercise combined the first two and included a cost element. For each of the three stated preference exercises respondents were presented with eight different paired choices, each pair comprising a different combination of levels - randomly produced - for the four attributes, and asked to say which they preferred in each case, even though they might not like either. The analysis of the choices provided the data from which to establish the relative importance and the monetary value of each component of the telematics system. The stated preference analysis was undertaken using ALOGIT. A report of the findings is being offered to automotive manufacturers to assist them in prioritising which features to include in their cars and how much their potential

customers value them. Telematics has the potential to revolutionise road safety, vehicle security and journey planning. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 09ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Line crossing by professional truck drivers and their acceptance of warning KATTELER, H, ITS Nijmegen University, Netherlands NEED, Y, Ministry of Transport, Netherlands This paper examines the degree in which professional drivers accept a voluntary lateral support system. This intelligent transport system gives an audible warning to the driver to correct his course in case of unintentional line crossing. The driver acceptance study was part of a Field Operational Test initiated by the Dutch Ministry of Transport involving truck drivers and bus drivers. The main objective of the lateral support system is to enhance traffic safety. The study discussed here provides an overview of the effects of the lateral support system as experienced by the drivers who had the system on-board half a year. The focus of this paper is on safety effects including the risk of unsafe behaviour evoked by an increased safety feeling.

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Speed cameras - measuring the impact on driver behaviour KEENAN, D, FaberMaunsell, UK Background A new concept of “hypothecation” has been piloted by the U.K. Department for Transport, allowing the funds raised from speed cameras to be retained by local authorities and re-invested into further road safety measures. The schemes demonstrated clearly the efficiency and financial benefits available from such an approach, but also highlighted the problems associated with public acceptability and consequently the enforcement of speed limits using speed camera systems. In some areas, such as in Hartlepool Cleveland, mobile cameras were deployed onto the streets accompanied by clear signs, warning of the potential presence of the cameras along the enforced sections of the network. However, the exact location of the mobile cameras and police operators were not made obvious to the passing motorists. The result was effective enforcement of the speed limits accompanied by a public backlash against the apparent “profiteering” of the local authority at the expense of the “unfairly-trapped” motorist. As a consequence of such reactions, the national hypothecation pilot scheme concluded that cameras should be targeted at accident black spots and overtly deployed onto the streets; that is painted bright colours to make their exact location obvious to passing drivers. This policy is being implemented on camera installations across the United Kingdom.

Speed Control and Accidents The link between reduced speeds and reduced accident frequencies has been clearly demonstrated by previous research (Taylor, Lynam and Kimber, 2000). The results of previous studies are as one would intuitively expect; the faster one drives the more chance there is of an accident occurring and of the accident having serious consequences. In other words for a given road, the faster the traffic flow the greater the accident frequency and severity. In this respect, speed cameras hold potential to improve the accident profiles of a large number of roads. Government Policy The UK government has actively promoted and implemented a number of speed reduction measures over recent years in an attempt to improve road casualty rates. These include the widespread use of road humps, home zones (using chicanes and physical barriers to slow traffic down), the “THINK!” publicity campaigns and the introduction of 20mph residential zones. However, due to proposed schemes involving large-scale expansion of hypothecation in the UK, the public now perceives speed enforcement cameras as central to current road safety policy. The aim stated by Lord Whitty at the launch of “New Directions in Speed Management - A review of policy” (DETR, March 2000) was that “….by 2010 we want speeding to be as socially unacceptable as drink driving has become.” This will be no mean feat, and given the widespread nature of the speeding problem requires a change in public attitude possibly greater than that experienced towards drink driving in the 70’s and 80’s. At the moment, there is a widening gulf between public and government opinion on speed camera enforcement, spurred on by opposition to cameras in significant elements of the press. A discrepancy often raised in the debate is that despite an increase in the number of cameras, the overall accident statistics across all roads (i.e. both with and without cameras) haven’t exhibited the expected improvements (“Speed Trap”, Channel 4 Dispatches, 06/07/02). The implication is that the methods being used are ineffective in positively changing driver behaviour, and are thereby not improving road safety. Research Proposed The research proposed in this abstract would thoroughly examine the effectiveness of various methods of speed camera enforcement by analysing impacts on driver behaviour and accident statistics, thus allowing conclusions to be drawn about which methods are the most effective. A significant proportion of the work has already been completed, and was featured in the April 2002 issue of Traffic Engineering and Control magazine, subsequently appearing on national UK television (“Speed Trap”, Channel 4 Dispatches, 06/07/02) and in a number of national newspapers (The Times, The Daily Mail - August 2002). This element of the work was a summary of an MSc. dissertation project, carried out in the summer of 2001 at the Institute for Transport Studies at Leeds University, and measured the spot speeds of a random sample of 4,000 drivers around four contrasting camera

sites. The approach adopted aimed to determine the “sphere of influence” of speed camera systems, and addressed the question of how they are affecting driver behaviour today, along the routes in question. Previous research had tended to concentrate on trends through time i.e. before and after installation studies or on attitudinal surveys; there seemed to be relatively little work examining the zones of influence of the enforcement systems that are being increasingly used in the UK. Scope of Study The sites examined in the MSc. research utilised two different genres of speed camera systems; three using differing arrangements of “GATSO” cameras, manufactured by SERCO systems, the fourth site in Nottingham using digital speed cameras, manufactured by Speed Check Services (SPECS). The GATSO camera is the older “grey-box” technology and consists of a wet film camera connected to speed detection equipment focused on a particular point on the highway. The exact location of enforcement is obvious to the passing motorist through the presence of a white painted road scale on the carriageway. In contrast to this older technology the SPECS digital system has no painted road-scales on the carriageway, and utilises CCTV-style cameras & licence-plate recognition software to monitor vehicle speeds over a measured length of highway. The system was piloted in Nottingham in August 2000. Basic operation is via two cameras mounted above the carriageway; the first reads the number plates of cars entering the link while the second, approximately 1km downstream, reads the plates of vehicles as they exit the controlled link. Computer software then matches up the two plate readings to calculate a measure of average speed derived from the time taken for vehicles to travel between the two cameras. Methodology The work proposed assesses speed camera effectiveness at each site in two ways: 1. Measurement of the speeds of a random sample of 200 drivers at key locations around the speed enforcement systems. For example, at a site using a single GATSO camera, the speeds of 200 cars are measured 500m before, at, and 500m after the camera’s exact location. This allows analysis of variations in speed around the exact location of the systems, and enables determination of the “zone of influence” of each method of enforcement; 2. Analysis of accident data for time-periods of equal length before and after the installation of the cameras. When considered in conjunction with the speed profiles this “completes the picture”, illustrating whether the cameras have achieved their objective of reducing accident and road-casualty rates. Speed surveys and limited analysis of accident trends were performed as part of the original MSc research. Rather than attempting to summarise this here, I would urge that the TEC article is consulted to gain an understanding of the interesting results obtained

and range of issues raised. (I can supply by email a PDF version of the TEC article – please contact david.keenan@fabermaunsell.com). At the time of the original work some of the camera systems had only been in place for 1 year, limiting the scope of the accident analysis that was possible. Therefore, in preparation for the AET conference I propose extending the work as follows: a) Examination of accident trends over approximately three-year periods before and after camera installation (3-years is a commonly accepted period for accident trends to show a statistically significant change). These time periods are now feasible and the relevant accident data has already been secured from the highway authorities; b) Due to the limited scope of available data the accident analysis performed previously only examined the changes in total accident numbers before and after the installation of speed cameras. No analysis was made of changes in accident severities or of changes to the locational pattern of accidents at each site. The updated work will examine both changes in total accident numbers and changes in the killed and seriously injured (KSI) rates often quoted by the government in support of camera schemes; c) To analyse spatial trends in accidents the work will also examine plots of accident locations in the times before and after the camera installations. This will allow the changes in accident numbers observed in (b) above, to be explained; finally…. d) The isolated GATSO at site 1 of the TEC paper (Scott Hall Road in Leeds) has recently been painted yellow, in line with the UK government’s policy decision to make cameras highly overt. Speed surveys were taken at this site as part of the original research when the camera was grey and less overt; therefore an ideal opportunity exists to isolate and analyse the impact of highly overt deployment on the speed profiles by performing further speed surveys over the coming months, and comparing these to the original profiles. Discussion of the reasons behind highly overt deployment (i.e. public acceptability, etc) and the subsequent impact of this policy on speed profiles at the Scott Hall Road GATSO site will then be possible. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 10i ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Indexes and models to analyse road safety within the aggregate approach POSTORINO, M N, University of Reggio Calabria, Italy Road safety is an important aspect of urban and extra urban transportation systems, particularly due to the high social costs it involves. While different actions have been started for resolving the problem of the atmospheric pollution caused by the vehicles moving on the transportation networks as well as different efforts have been made to limit the environmental pollution at the end-of-life of the vehicles, in the safety field the situation is still very serious. The resources devoted to the road safety each year are largely smaller than the real needs; the situation is various from Country to Country, both for the differences in the regulations in force and for the different sensibility of users to the safety problem. Many studies carried out in this field linked the risk of accidents, the percentage or the number of accidents, the number of fatal accidents (dependent variables) to different

factors or explanatory variables (independent variables) such as: age, and/or sex of the driver, expert or inexpert drivers, speed, length of the network, use of the safety belts, meteorological conditions and so on. Other kinds of studies concern the aggregate description of the accidents occurred in a region, by using indexes for identifying the trend of some relevant variables (total number of accidents, number of fatal accidents, and so on, in a given location and in a given time period). Studies already carried out attribute 10-11% of accidents to the non-observance of the safety distance, 15% to driver inattention, 2-3% to meteorological conditions and 52% to undefined causes, among which the user guide behaviour. Then, undefined factors are one of the most important causes of accidents, but the knowledge of the main causes of accidents (not due to human factors) is a crucial aspect for the analysts of the transportation systems if some intervention have to be made for reducing the number of accidents (and mainly the fatal accidents). Road accidents can be considered the consequence of the interactions among the users of the urban or extra urban transportation system and the environment in which they move, or in other words, the consequence of the interaction among human factors, technological factors and environmental factors. An accident is then the result of a sequence of actions and events due to this interaction, whose strong complexity makes difficult to establish which factor could be the main cause of the accident and how little variations on the initial conditions could transform a slight accident in a fatal one. Models for the analysis of accidents can be specified at different aggregation/disaggregation levels, also due to the availability of the relative data base. Generally, the use of disaggregate models presupposes the realization of specific data base collections, in order to register all accident data, at a microscopic level, that occur in a prefixed area and in a time interval as large as to obtain a representative sample of the event. On the contrary, the construction of aggregate models does not require this kind of data collection, because of the macroscopic level of the analysis; in this case the data collected by police (or other institutional figures) allow a preliminary analysis to be carried out, and they can be used to obtain the probability that an accident will occur in a prefixed area as a function of the mobility characteristics, the transport system and the socio-economic characteristics of the area itself (see, for example, Broughton e Markey, 1996; Broughton, 1996; Aron et al., 1997; Broughton, 1997; Brouwer, 1997; Rodrigues et al., 1997; Ernvall, 1997; Persaud et al., 1997, Postorino e Sarnè, 2001). On the other hand, the accident aggregate analysis is really important because it support the decisions and the actions addressed to assure a greater level of safety. Furthermore, it is addressed to evaluate the time-space characteristics of the road safety. To summarize, the main aims of the aggregate analysis can be identified in the following: • identification of the main factors related to the accidents; • aggregate check of the attainment of specific objectives (as increase of the

safety degree of the transportation system, or a part of it); • analysis of the space distribution of different kinds of accidents in order to locate “black points”; • analysis of the accident time variation in order to establish the effectiveness of the actions taken to reduce the number and severity of accidents.

On the basis of the previous considerations, in this paper after an analysis of the main

aggregate approaches used to study road accidents, a model has been specified and calibrated for a prefixed area, by using official sources of data. Furthermore, a comparison among safety indexes and calibrated models, by using the same data base, has been carried out. In fact, the aggregate analysis can be carried out by using two methodologies: • safety indexes • models.

Indexes, given to their specific nature, can be used only to analyse the problem, while models can be used both to analyse and forecast. Different indexes have been constructed, in order to establish the relationship between accidents and, respectively, human factors and environment. Referring to models, different kinds of models have been proposed in literature, that can be grouped as follows: • probabilistic models • time series models • Bayes models.

In this paper, following the first approach, the probability that an accident could verify at time t in location i, Xit, has been specified following a Poisson distribution and as a function of the Poisson parameter that represents the mean and the variance of the random variable 'number of accidents'. This parameter has been specified in order to take into account the relevant variables related to the accident occurrence. The variables, selected in the available data base, refer to the transportation system, both in terms of infrastructures and regulation. Two kinds of models have been specified and calibrated, referring to roads and intersections. In fact, it has been considered that this separation can implicitly consider the specific behaviour of users in the two different conditions. The results in terms of goodness of fit of the specified models are very satisfactory and some interesting considerations have been carried out in terms of link between accidents and explanatory variables. Similarly interesting results have been obtained in terms of indexes, particularly in terms of time-space variations. Further developments concern the estimation of a behavioural probabilistic model to analyse and forecast the number of accidents given the transport network and the socio-economic characteristics. AA. VV. (1998) “DUMAS: Developing Urban Management and Safety – Work package 4: Accident Investigation”. Progetto DUMAS. Amis G. (1996) “An application of generalised linear modelling to the analysis of traffic accidents”, Traffic Engineering + Control, December Aron M., Biecheler M.-B., Hakkert S., Peytavin J.-F. (1997) “Headways, rear-end collisions and traffic: the case of French motorways”, 7th International Conference on

Traffic Safety on Two Continents. Ben-Akiva M., Ceder A., Cheng L.-H., Liss M. (1988) ”Estimation of intersection traffic safety improvements”, Final Report, MIT, Centre for Transportation Studies, Cambridge, Massachusetts. Bergel R. (1997) “Multivariate modelling of accident risk on the national road network”, 7th International Conference on Traffic Safety on Two Continents Broughton J., Markey, K.A. (1996) “In-car equipment to help drivers avoid accidents”, TRL Project Report 198: Transport Research Laboratory. Crowthorne Broughton, J. (1996) “ A study of causation factors in car accidents”, Road Safety in Europe Conference, Birmingham, 9-11 September. Brouwer M (1997) “Road safety information system: Key information supporting traffic safety policy in the Netherlands”, 7th International Conference on Traffic Safety on Two Continents. Ernvall T. (1997) “Risks exposures and accident data”, 7th International Conference on Traffic Safety on Two Continents. Hauer E. (1992) “Empirical Bayes approach to the estimation of ‘unsafety’: the multivariate regression method”, Accident Analysis and Prevention, vol.24 No5 Hauer E. (1996a) “Identification of ‘Sites with Promise’”, Transportation Research Board Annual Meeting Preprint 960995 Hauer E.(1996b) “Statistical test of the difference between expected accident frequencies”, Transportation Research Board 75th Annual Meeting Higle J.L., Witkowski J.M. (1988) “Bayesian identification of hazardous locations”, Transportation Research Record, 1185, TRB Jarret D. (1997) “Assessing the safety effect of treatment using data from a number of sites”, 7th International Conference on Traffic Safety on Two Continents Koornstra M.J. (1996) “The quantifying of road safety developments”, Proceedings of the Conference Road Safety in Europe, Birmingham,U.K. Persaud B., Cook W., Kazakov A. (1997) “Demonstration of new approaches for identifying hazardous locations and prioritizing safety treatment”, 7th International Conference on Traffic Safety on Two Continents. Postorino M.N., Sarnè G.M.L. (2001) “Cluster analysis for road accident investigations”, Proceedings of Urban Transport 2001, WIT. Postorino M.N. (2002) “Sicurezza: analisi e modelli”, Rilievi, Modellizzazione e Controllo del traffico veicolare, Collana Trasporti, FrancoAngeli editore. Rodrigues E., Picado-Santos L. (1997) “A study on road accident in urban environment”, 7th International Conference on Traffic Safety on Two Continents. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 10ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Disaggregate road accident analysis for safety policy and measures: theoretical aspects and application

RUSSO, F, University Mediterranea of Reggio Calabria - DIMET, Italy VITETTA, A, University Mediterranea of Reggio Calabria - DIMET, Italy In this paper a method is proposed for analysing road incidents and defining safety policies and safety measures. The method uses the scenario incident approach proposed by Brenac and Megherby (1996) and Brenac et al. (1996) where some scenarios were defined with statistical approach. This approach was extended inside a theory and it is applied to calibrate the scenarios on an Italian extra-urban road considering real data.

The importance of the proposed paper consists in the proposal of a global method for specifying and calibrating the incident scenario and in scenario calibration with a quantitative approach. The proposed method can be applied in the place where the frequency of incidents is greater than the corresponding value in other similar areas. This area will be called the study area. In this place a specific approach with in-depth investigations has to be applied for: incident detection; incident analysis; safety measures application; system monitoring. The first step begins with incident detection measurement 'in time' and 'on the scene' in the study area. The 'in time' measurements are the microscopic traffic flow (counted or simulated) and ambient characteristics during the impact; the 'on the scene' measurements concern infrastructural characteristics, users and vehicles. The data have to be collected by an expert team and can be: macro or micro. The macro data are relative to socio-economic characteristics, supply and demand information, while the micro data are relative to vehicles, users and infrastructural characteristics useful for incident reconstruction. The data relative to the incidents of the study area have to be analysed to identify the common events, incident factors relative to the users (human factors), infrastructure and vehicles and their reciprocal interactions. For the analysis two different methodological analyses can be used: macroscopic or microscopic. Macroscopic analysis concerns a large area (urban area, central business district, etc.) and estimates the probability of an incident occurring in relation to a set of variables that are generally macro. Microscopic analysis concerns an infrastructural element (road, junction, parking area, etc.) and defines common elements in the incidents in order to define safety measures for avoiding impacts in relation to a set of variables that are generally micro. With microscopic analysis the incident scenario can be generated. After data analysis safety infrastructural or supply management measures have to be applied on the system. The safety measures are strictly connected with the common factors extracted from data analysis and in particular with incident scenario and may be of various types: user education, engineering measures, traffic organization, traffic control, enforcement. The last step of the method consists in monitoring the effect generated with the safety measure applied on the system in order to verify pre-defined targets. The proposed method is applied on a freeway in the extra-urban area of Naples (Italy). A set of 63 road incidents was detected with an expert team in a study area and for each incident more than 500 microscopic measurements were made on the scene. The data were analysed with the microscopic approach and the proposed methodology is applied for calibrating incident scenarios for an extra-urban road in Italy. For each scenario the safety measures are defined and are communicated to infrastructural managers for application on the system. References Brenac T., Megherby B. (1996), “Diagnostic de sécurité routière sur une ville: intéret de l’analyse fine de procédures d’accidents tirées aléatoriement”, Researche Transports

Sécurité, 52, 59-71. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 10iii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

RES, a network disaggregate model for road risk BERGEL, R, INRETS, France This paper deals with a model for road risk, developped for the French Road Safety Observatory, under two contracts concluded between the Ministry of Transportation, the University and Inrets. According to the Drag-type approach, time series modelling including exogenous variables has been applied on a monthly basis to the triangle 'risk exposure/risk/gravity', for the period 1975-1999. We mainly describe the model related to the monthly number of injury accidents and fatalities,agregated on the whole territory, and disagregated by road network (main roads, motorways, secondary roads, urban network). The exogenous variables measure risk exposure, the climatic conditions and the calendar configuration. The elasticity values, of the numbers of injury accidents and fatalities with respect to these determinants are discussed, and compared with the values obtained in the litterature. We give examples,of the road safety indicators evolution over the period, and discuss the model's performance. Special attention is paid to the climate influence. On both main roads and motorways, the two networks on which the traffic volume is measured, the climate effect is separated in two parts: a direct effet, due to the drivers behaviours modification, and an indirect effect through risk exposure.The results obtained, related to temperature, rainfall and frost, are discussed. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 11i ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Highway safety evaluation methods - a comparative analysis DATTA, T K, Wayne State University, USA SCHATTLER, K, Wayne State University, USA SHARMA, S, Wayne State University, USA Evaluation of highway safety improvement projects and programs is essential to identify the successes and failures of various infrastructure and traffic control related countermeasures which are often implemented to alleviate traffic crashes and injuries. Traditionally, practitioners use a “Before & After” (B&A) study to evaluate the effectiveness of safety improvement projects. Researchers however, tend to question

the use of a B&A study methods. They argue that in many instances, high crash locations experience fluctuating crash frequencies over time. Thus, the use of one or two years of B&A data may result in a significant change in crash experience which evaluators often attribute to the countermeasures, whereas such changes may be due the “ regression to the mean” phenomenon. During the past decade, the ‘Empirical Bayes’ method of evaluation of highway safety countermeasures has become quite popular in North America. This method requires the use of a large number of control sites to make the correction for “regression-to-the-mean” effect of the study site(s)’s expected “after” crash experience without treatment. Some researchers use B&A with comparison groups for effectiveness evaluation, while others use a ‘Comparative Parallel’ study. There are issues related to all such methodologies. A study of the effectiveness of several low cost intersection improvement projects have been completed in Michigan and their effectiveness has been tested using several of the noted methods. The results of this study indicate that there are drawbacks of using all the methods, in spite of advocates of some methods stating otherwise. For example, the use of a simple B&A study where the ‘before’ crash data shows fluctuating frequencies may lead to an incorrect estimate of the ‘after’ crash experience without treatment. In such cases, the ‘B&A with control’ type of methodology will allow an evaluator to capture the true impact of the treatment. The use of a large number of control sites where all the critical independent variables of these sites are not controlled, as used by some researchers in the ‘Empirical Bayes’ method, may not necessarily yield realistic results. Additionally, the available human resources in state and local highway agencies in North America for performing these safety evaluation activities must be considered in selecting an appropriate evaluation methodology. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 11ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Modelling safety-related driving behaviour: impact of parameters values BONSALL, P, ITS, University of Leeds, UK LIU, R, ITS, Univesity of Leeds, UK YOUNG, W, Monash University, Australia 1. Introduction Traffic micro-simulation models make assumptions about the safety-related behaviour of drivers. The question is whether these assumptions should reflect safe behaviour or actual behaviour. It is clear that, in reality, drivers often engage in seemingly unsafe behaviour (e.g. running red lights at signalized intersections, or following cars too closely on motorways) in order, for example, to reduce their journey time. Should models seek to replicate such behaviour? On the one hand it might be held that models should be as close to real life as possible. On the other hand, it could be thought unethical to design a scheme based on a tool which assumes unsafe behaviour if this

could lead to the adoption of designs which are known to be unsafe. In exploring the issue, we first question where the key parameters in well know traffic micro-simulation models have come from and whether they represent real behaviour or some idealised safe behaviour. We then investigate the sensitivity of model predictions to the value of key safety-related parameters and discuss the whole question of the representation of unsafe situations in traffic microsimulation models and their consequences. 2. Safety-related parameters in traffic simulation models Vehicle interactions and drivers’ behaviour are generally represented in microsimulation models through car-following, gap-acceptance, lane-changing models. Car-following models represent the longitudinal interaction between vehicles. The acceleration of the following vehicle is modified in the light of the relative speed and position of the preceding vehicle. The parameters required to determine such longitudinal progress include: the desired speed, the desired minimum headway, the reaction time, the rate of acceleration and the rate of deceleration. Gap-acceptance models are used to determine how a vehicle from a low priority flow will cross, or merge into, a higher priority flow. The key parameter for such models is the critical acceptable gap for the manoeuvre being contemplated. Some models allow the critical gap to be reduced to represent the frustration of the waiting traffic in presence of heavy traffic – with parameters used to indicate the stimulus required to induce use of the reduced gap and the reduced gap itself. Others allow for the fact that vehicles in the priority flow may deliberately slow down in order to create gaps for the low priority flow – in which case at least one parameter will be required to indicate their willingness to create gaps. Lane-changing models consider the individual driver’s intention and ability to change lanes. The driver’s intention to change lanes may be triggered when the time advantage to be gained by changing lanes exceeds some critical value. Some models may allow drivers to anticipate the need for a change of lane, with parameters required to determine how far ahead the drivers anticipate. The ability to change lanes is generally modelled in a way which is analogous to a gap-acceptance model. The paper will present a full list of the parameters identified, indicate commonly adopted values and the sources of those values. 3. The consequences of changing the value of safety-related parameters 3.1 The consequences of ‘unsafe’ driving It is not difficult to think of a range of unsafe driving behaviours, such as: • adoption of inadequate headways in fast moving traffic; • speeding (in excess of the legal limit or in spite of local circumstances); • excessive reliance on the vehicle’s brakes;

• reckless overtaking (e.g. where sight-lines are inadequate); • passing traffic signals at amber (or even red).

We will consider the first of these in a little more detail. Behavioural research based on carefully observed experiments in laboratories and on the road suggests that drivers’ minimum reaction times lie in the range 0.8-2.0 seconds. Allowing for typical reaction time and stopping distance, a safe headway on a 110 kph road would generally need to be in excess of 4 seconds and yet headways as low as 0.5 seconds have been observed on such roads. Recent research by Oates (1999) suggested that almost 50% of drivers on a congested stretches of a motorway were driving with headways at or below two seconds and that almost 25% were driving with headways at or below one second. Simple calculation indicates that, in smooth conditions and constant speed, the flow achievable with a 0.5 second headway would be about eight times that achievable with a 4 second headway. Similar arguments can be made in respect of each of the cases mentioned above. Unsafe driving will generally lead to enhanced system performance but when, as is inevitable, there is an incident, the results can be catastrophic. However, provided that incidents remain relatively rare events, it is possible to conclude that if everyone were to drive in strict accord with guidelines and regulations, the effective capacity of the network would be reduced below the levels currently observed. Various researchers have commented on this rather uncomfortable fact. For example, in his study of signalised intersections, Pretty (1974) found that traffic signals improved capacity at an intersection previously under police control only because drivers used the amber and all-red periods. 3.2 Analysis In order to illustrate the general argument made above, the DRACULA traffic micro-simulation model (Liu et al, 1995) was used to explore the impact that changes in key behavioural parameters might have on various model estimates of system performance. The results reported here relate primarily to the total travel time in the test network since this is the indicator of system performance most widely used to inform investment decisions. One of the tests conducted was designed to show how assumptions about the distribution of one aspect of aggressive driving (in this case the rates of acceleration and deceleration) can affect the predicted performance of a scheme. The tests relate to the introduction of partial signalisation at a roundabout just off the M25 near Heathrow Terminal 5. The mean values of the acceleration/deceleration distributions used in the tests are shown in Table 1 (note that traffic at the site is 10% HGV and 90% car). The tests relate to two flow level scenarios; a current flow and a future flow at twice the current level – as can be expected when the new Terminal opens. The results of the tests are shown in Table 2. As expected, the effect of the signalisation scheme is dependent on the level of flow. At the current (low) flow levels, the signalisation would lead to 5-11% increase in journey times. With increased flow, however, the signalisation scheme leads to a very marked reduction in journey

time (59-64%). The assumed level of acceleration/deceleration affects the predicted impact of the scheme. If a more aggressive level of acceleration/deceleration is assumed, journey times are reduced (ranging from 2% to 25%). The reduction is more significant under normal priorities and under the high flow scenario (-25%). The net result is that the assumption of more aggressive acceleration/deceleration causes a doubling of the disbenefit associated with signalisation under current flow conditions. It is clear that the assumptions about levels of acceleration and deceleration can profoundly affect the prediction of scheme benefits and that this effect differs according to the flow level. 4. Summary The paper identifies the key parameters of traffic simulation models and notes that several of them have been derived from theory or informed guesswork rather than observation of real behaviour and that, even where they are based on observations, these may have been conducted in circumstances quite different to those which now apply. Tests with DRACULA demonstrate the sensitivity of model predictions – and perhaps policy decisions – to the value of some of the key parameters. It is concluded that, depending on how the model predictions are being used, use of realistic-but-unsafe parameter values could result in the adoption of unsafe designs. However, it is noted that this problem can be overcome by paying attention to the safety aspects of designs and that, in general, the use of realistic values is to be preferred. The possibility of using traffic simulation models to produce estimates of accident potential is discussed and the difficulties involved in doing so are discussed. REFERENCES Liu, R., Van Vliet, D. and Watling, D. P. (1995) DRACULA: Dynamic Route Assignment Combining User Learning and microsimulation. Proceedings of PTRC Summer Annual Conference, Vol E, 143-152. Oates, A. (1999) A study of Close Following on the M62. MSc Dissertation, ITS, University of Leeds. Pretty, R. (1974) Police control and intersections. Proc. 7th Australian Road Research Board Conference, 7(4), 83-95. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 11iii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

A GIS based accident system for reducing road accidents HASSEEA, R, Mott MacDonald, UK Accident analysis plays an important part in the strategy to reduce road accidents. In the past, the main analysis tools available to the road safety engineer were paper maps allied to databases like Excel spreadsheets. Accidents were identified on the map using road segments or an area-based location. This was very time consuming process and lacked accuracy. However, nowadays Geographical Information Systems (GIS) have revolutionised the whole framework of accident processing and analysis.

A GIS Accident Processing and Analysis system was developed using MapInfo GIS software. This paper aims to describe how GIS can assist in the processing and analysis of accidents. The use of analyses tools such as cluster, density, sliding scale or blacksite analyses are described in detail. Finally, the paper gives an insight into the current development of an internet based GIS accident system.

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Clustering and profiling traffic roads by means of accident data BRIJS, T, Limburg University, Belgium GUERTS, C, Limburg University, Belgium VANHOOF, K, Limburg University, Belgium WETS, G, Limburg University, Belgium In Belgium, every year approximately 50.000 injury accidents occur in traffic, with almost 70.000 victims, of which 1.500 deaths (Belgian Institute for Traffic Safety, 2000). Not only does the steady increase in traffic intensity pose a heavy burden on the society in terms of the number of casualties, the insecurity on the roads will also have an important effect on the economic costs associated with traffic accidents. Accordingly, traffic safety is currently one of the highest priorities of the Belgian government. Cameron (1997) indicates that clustering methods are an important tool when analyzing traffic accidents as these methods are able to identify groups of road users, vehicles and road segments which would be suitable targets for countermeasures. More specifically, cluster analysis is a statistical technique that groups items together on the basis of similarities or dissimilarities (Anderberg, 1973). In Ng, Hung and Wong (2002) a combination of cluster analysis, regression analysis and Geographical Information System (GIS) techniques is used to group homogeneous accident data together, estimate the number of traffic accidents and assess the risk of traffic accidents in a study area. The results will help authorities effectively allocate resources to improve safety levels in those areas with high accident risk. In addition, the results will provide information for urban planners to develop a safer city. Furthermore, according to Kononov (2002), it is not possible to develop effective counter-measures to improve traffic safety without being able to properly and systematically relate accident frequency and severity to a large number of variables such as traffic, geometric and environmental factors. Lee, Saccomanno and Hellinga (2002) indicate that in the past, statistical models have been widely used to analyze road crashes. However, Chen and Jovanis (2002) demonstrate that certain problems may arise when using classic statistical analysis on datasets with such large dimensions such as an exponential increase in the number of parameters as the number of variables increases and the invalidity of statistical tests as a consequence of sparse data in large contingency tables. Data mining is the nontrivial extraction of implicit, previously unknown, and potentially useful information from large amounts of data (Frawley et al, 1991). Therefore, data mining methods are particularly useful in the context of large data sets on road accidents to identify the relevant variables that make a strong contribution towards a better understanding of accident circumstances.

The identification of geographical locations with high accident risk by means of clustering techniques and profiling them in terms of accident related data and location characteristics by means of data mining techniques must therefore provide valuable input for government actions towards traffic safety. In the first part of this research, an innovative method based on latent class clustering (also called model- based clustering or finite mixture modelling) (McLachlan and Peel, 2000) is used to cluster traffic roads into distinct groups based on their similar accident frequencies. The data that will be used are obtained from the Belgian “Analysis Form for Traffic Accidents” that should be filled out by a police officer for each traffic accident that occurs with injured or deadly wounded casualties on a public road in Belgium. These traffic accident data contain a rich source of information on the different circumstances in which the accidents have occurred: course of the accident (type of collision, road users, injuries, …), traffic conditions (maximum speed, priority regulation, …), environmental conditions (weather, light conditions, time of the accident, …), road conditions (road surface, obstacles, …), human conditions (fatigue, alcohol, …) and geographical conditions (location, physical characteristics, …). On average, 45 attributes are available for each accident in the data set. More specifically, this analysis will focus on 19 central roads of the city of Hasselt for 3 consecutive time periods of each 3 years: 1992-1994, 1995-1997, 1998-2000. The observed accident frequencies are assumed to originate from a mixture of density distributions for which the parameters of the distribution, the size and the number of segments are unknown. It is the objective of latent class clustering to ‘unmix’ the distributions and to find the optimal parameters of the distributions and the number and size of the segments, given the underlying data. A 3-variate Poisson distribution (Y1, Y2, Y3) with one common covariance term is defined (Li et al, 1999) with Yi = the number of accidents in period i and all X ‘s independent univariate Poisson distributions with respective parameters (ë1, ë2, ë3, ë123). Since the occurrence of accidents over several time periods may be related (e.g. due to bad infrastructure), correlations between the observations in each latent class cluster are allowed. Therefore, the parameter ë123 is identified, which can be considered as a covariance factor that measures the risk of the area common to all time periods (Karlis, 2000). To estimate the parameters, we maximize the loglikelihood using a non-linear iterative fitting algorithm (nlp). To prevent the algorithm from finding a local but not a global optimum, we use multiple sets of starting values. Next, we observe the evolution of the loglikelihood for different restarts of the algorithm. Finally, to determine the number of segments (k) in the mixture model different information criteria (Akaike (AIC), Consistent Akaike (CAIC) and Bayes (BIC)) are used to evaluate the quality of a cluster solution (Schwarz, 1978). Results show that, although the loglikelihood of the model increases when the number of segments increases, the information criteria will not choose the maximum possible segments to cluster the data. Considering the model complexity, the AIC selects 3 clusters whereas the CAIC and the BIC select only 2 clusters. This difference can be explained by the fact that the AIC does not consider the size of the dataset, whereas the CAIC and the BIC do penalize for this factor. Furthermore, in the 2-components common covariance model the average number of accidents increases each period for

the first cluster and decreases each period for the second cluster. Additionally, the observed average accident rate per period for cluster 1 is mainly dependent on the average accident frequency of the concerning period and less on the covariance factor. For cluster 2, the covariance term does play an important role in the observed average accident rate per period. This can be explained as for this cluster there is a strong common factor in all periods that has to do with the accident ‘risk’ on these roads. Analogously, the results for the 3-components common covariance model can be analysed. Here, one should remark that the value for ë1 in cluster 1 and the value for ë2 in cluster 2 is very small, meaning that the observed average accident frequency for cluster 1 in the first period and cluster 2 in the second period will mainly be influenced by the overall accident risk on the roads. In the second part of this paper, the data mining technique of association rules is used to profile each cluster of traffic roads in terms of the available traffic accident data. The strength of this approach lies within the identification of relevant variables that make a strong contribution towards a better understanding of the accident circumstances for each group of traffic roads (Geurts et al, 2002). Since the clusters show different results for the overall accident ‘risk’ on the roads, one could expect that not every accident variable will be of equal importance when describing the different groups of traffic roads. Therefore, a comparative analysis between the accident characteristics of the different clusters is conducted, which provides new insights into the complexity and causes of road accidents. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Session TS 12ii ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Estimating the relationship between accident frequency and homogenous and non-homogenous traffic flow

HISELIUS, L, University of Lund, Sweden Introduction Accident prediction models are central when discussing traffic safety analysis. Using these models, we try to allocate resources in the best way by identifying dangerous locations that we may need to take care of. When identifying these locations we have to control for the exposure, i.e. the traffic flow, giving cause the accidents. Research indicates that the relationship between the number of accidents and traffic flow is non-liner, i.e. the ratio is not constant. For instance, an early report from Vickrey (1968) suggests that the marginal accident rate is 1.5 times the average accident rate and according to Hauer and Bamfo (1997) and a majority of the results reviewed in Ardekani et al (1997), the accident rate even decreases with an increasing number of vehicles. These results among others indicate that the accident rate is not proper to use in order to compare the safety of sites with different traffic flow. There is then an interest in studying the relationship between the accident frequency and the traffic flow more thoroughly. This is not an easy task, though, since necessary data can be hard to find. Studies estimating accident prediction models sometimes use observations from similar locations with different average daily traffic volume in order to estimate the relationship between the accident frequency, the accident rate and the traffic flow. However, in these cases there will always be an uncertainty regarding how similar the locations in fact are. Site-specific factors, that are not considered, may then influence the result. Another factor complicating the task of estimating accident prediction models is whether

the number of different road user groups should be taken into consideration. The vehicles on the road are very much inhomogeneous with respect to weight, average driving speed, etc, which indicates that they may affect the traffic safety differently. There is then an interest in estimating the relationship between the number of accidents and the traffic flow separated for different vehicle types. However, since there are even more difficulties finding data separated on the flow of different traffic groups than when studying a homogeneous flow, there are only a few empirical studies made analysing this matter. Aim The study presented here has the advantage of studying the same locations at different hourly traffic flows and having data on hourly traffic flow separated on the number of cars and lorries. The aim of the study is to estimate the relationship between the accident frequency and the traffic flow, treating the traffic flow in two different ways. In the first model the traffic flow is defined as the number of vehicles per hour treating the traffic flow as if consisting of homogenous vehicles. In the second model the traffic flow is defined as the number of cars and the number of lorries per hour in order to take into consideration that different road user groups may affect the traffic safety differently. Data Data is collected from 83 road sections in rural areas of Sweden, where the Swedish National Road Administration continuously counts the number of passing vehicles. The assumption is made that the counted traffic flow at a stationary place is valid along the section. Information on police reported accidents with personal casualties, which have occurred on the studied road sections, is collected from 1989 to the middle of 1995. Given the time and date of the accidents that have occurred on the road sections, the hourly traffic flow that prevailed at the time of each accident is obtained. Furthermore, in order to calculate traffic flow frequencies, information on the number of hours that each traffic flow has been observed during 1990 is also collected on the assumption that this is a representative year. Only accidents occurring on sections without intersections are included. Accidents involving animals are excluded together with accidents that may be considered specific for each road section. Since it is not possible to obtain information on driving speed, the analysis will be made bearing in mind that the estimated effect of the traffic flow may also be an effect of speed adjustment. Moreover, there are several other factors likely to influence the occurrence of accidents, e.g. weather, road conditions, and drivers' characteristics. In order to take some of these factors into account, daylight accidents are studied separately as well as single and multivehicle accidents. We distinguish between four road types, road type I with speed limit 70 km/h and road width 6-9,7 m, road type II with speed limit 90 km/h and road width 6-7,9 m, road type III with speed limit 90 or 110 km/h and road width 8-13 m without separated road lanes and road type IV, motorways, with speed limit 90 or 110 km/h. The number of accidents that occurred on the studied sections of road type I, II, III and IV is 59, 83, 179 and 186 respectively. Model The relationship between the accident frequency and the traffic flow is estimated

empirically using regression analysis. Both the Poisson and the Negative Binomial distribution are applied. In order to adopt the result on time periods and road systems of different length the accident frequency is defined as the expected number of accidents per hour and kilometre taking into consideration the number of hours and kilometres that each road type has been studied. An exponential function is estimated, since this function ensures that the expected number of accidents is a positive number and the use of this model function is being supported by studying the data visually and by analysing the residuals. Results The result generally suggests a good fit for both the Poisson and the Negative Binominal regression model. All estimated parameter values are significantly different from zero. Furthermore, for all road types, except for road type I, the estimated exponent is significantly different from one when treating the traffic flow as homogenous. Thus we may reject the hypothesis that the expected accident frequency increases in proportion with the traffic flow for these road types, i.e. that the accident rate is constant. Instead, an additional vehicle lowers the accident rate and increases the traffic safety. Accidents that occur at daylight are also studied. For the majority of road types, the estimated parameters are lower than when studying accidents that have occurred throughout the day. The difference is, however, not significant. When studying different accident types the result indicates that the accident rate for single vehicle accidents decreases with increasing number of vehicles, whereas the accident rate for multivehicle accidents is constant or increasing. The result, when separating on type of accident, seems logical since the risk for a single vehicle accident ought to be lower at hours with heavy traffic than at hours with few vehicles on the road. Consequently, the risk for a multivehicle accident ought to increase with an increasing number of vehicles. When studying the traffic flow for cars and lorries separately, a rather different result is received. For road type I and IV, the expected number of accidents increases more than proportionally with the number of cars per hour, i.e. that the accident rate increases. For road type II and III, the exponent is not significantly different from one, however. The estimated exponent for the flow of lorries is generally negative and different from zero. The result suggests that the number of lorries per hour lower the expected number of accidents independently of the flow of cars. The estimates when studying accidents occurring at daylight are not significantly different from those when studying all accidents together. The results for single and multivehicle accidents are similar to that of homogenous traffic flow when studying the flow of cars. The flow of lorries is again affecting the traffic safety positively, lowering the accident rate for both single and multivehicle accidents. Conclusions The result of this study indicates that there is important information lost if no consideration is taken to differences between vehicle types when estimating the marginal effect of the traffic flow. The accident rate decreases when the traffic flow is treated as if homogeneous. Since cars constitute the main part of the traffic flow, one may expect the same result when studying the flow of cars. However, when cars are studied the result suggests that the accident rate is constant or increases. The result with respect to the flow of lorries may be described as an effect of people’s unease when sharing the road-space with a lorry. The presence of a lorry may cause other road users attention to increase, which in its turn lowers the number of accidents occurring.

References Ardekani, S., Hauer, E. and Jamei, B. (1997) Traffic Impact Models in Traffic Flow Theory - A State-of-the-Art Report, Gartner, N. et al (ed). Project Report, Oak Ridge National Laboratory. Hauer, E., Bamfo, J., 1997. Two tools for finding what function links the dependent variable to the explanatory variables. Paper presented 5-7 November 1997 at the ICTCT Conference, Lund. Vickery, W. S. (1968) Automobile Accidents, Tort Law, Externalities and Insurance. Journal of Law and Contemporary problems, vol. 33, pp: 464-484.