Provision of Travelway Space for Urban Public Transport in ... · Provision of Travelway Space for Urban Public Transport in Developing Countries United Nations Centre for Human Settlements

Provision of Travelway Space for Urban Public Transport inDeveloping Countries

Table of ContentsProvision of Travelway Space for Urban Public Transport in Developing Countries.................................1

FOREWORD..........................................................................................................................................1I. TRAVELWAYS FOR PUBLIC TRANSPORT IN DEVELOPING COUNTRIES...................................2

A. Introduction..................................................................................................................................2B. Characteristics of travel demand.................................................................................................3C. Low−cost mass transit options....................................................................................................8D. The impact of public transport segregation...............................................................................22E. Planning considerations.............................................................................................................25F. Strategy for development...........................................................................................................34BIBLIOGRAPHY............................................................................................................................36ENDNOTES...................................................................................................................................39

II. CASE STUDY: BUSWAY IN ANKARA − AN INTERMEDIATE, LOW−COST ACTION TO IMPROVE PUBLIC TRANSPORT1.....................................................................................................39

A. Urban transport in Ankara..........................................................................................................39B. The development and performance of a busway in Ankara......................................................44C. Lessons to be learned...............................................................................................................53D. New developments in Ankara mass transport...........................................................................55REFERENCES...............................................................................................................................55ENDNOTES...................................................................................................................................55

III. CASE STUDY: THE BRAZILIAN EXPERIENCE IN PLANNING, IMPLEMENTING AND OPERATING PUBLIC TRANSPORT ON SEPARATED ROAD AND LIGHT RAIL TRAVELWAYS1............................................................................................................................................................55

A. Introduction................................................................................................................................56B. Medium−capacity public−transport modes................................................................................59C. Lessons from the Brazilian experience......................................................................................69REFERENCES...............................................................................................................................75ENDNOTES...................................................................................................................................78

IV. CASE STUDY: PROVISION OF SEPARATED TRAVELWAYS FOR PUBLIC TRANSPORT − IN METRO MANILA, THE PHILIPPINES1..........................................................................................78

A. Urban development and transport.............................................................................................78B. Development of LRT system.....................................................................................................87C. EDSA bus lanes........................................................................................................................94D. Lessons from the case studies................................................................................................107ENDNOTES.................................................................................................................................112

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Provision of Travelway Space for Urban Public Transport inDeveloping Countries

United Nations Centre for Human Settlements (Habitat)Nairobi, 1993

The designations employed and the presentation of the material in this publication do not imply the expressionof any opinion whatsoever on the part of the secretariat of the United Nations concerning the legal status ofany country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers orboundaries.

Mention of firm names and commercial products does not imply the endorsement of the United Nations.

FOREWORD

The demand for public transport services is growing steadily in the large cities of developing countries. This ismost evident along the transport corridors linking ever−expanding suburban areas to main concentrations ofemployment and services, in particular, to city centres. Sustainable urban transport development depends to agreat extent on the capacity and quality of services along these corridors, not only for obvious economic andenvironmental considerations, but also with regard to social equity, as these corridors largely determine themobility of the urban poor who are pushed by land−forces to urban fringe areas and suburban localities.

Most developing−country cities with a population exceeding 2 to 3 million already have at least one heavilyloaded corridor on which public transport should offer a capacity and speed of travel better than what busesoperating in mixed traffic conditions could provide. Public authorities when seeking such alternatives usuallyfocus on heavy−rail transport systems such as metro. Metro systems are, perhaps, indispensable to supportthe development of very large cities but these are neither affordable nor a viable option in most intermediatecities. These cities will have to look for less expensive solutions using, as priority, already available publictransport infrastructure. Providing public transport with partly segregated and exclusive travelway spaceincreases both capacity and operating efficiency of any public transport system. Separated travelways notonly ease or alleviate the interference from other traffic and thus the impact of transport congestion on publictransport, but also allow the application of public transport operating regimes which further add to the capacityand quality of services.

The objective of this publication is to promote public transport systems which will be significantly lessexpensive than metro and yet provide relatively high capacity and speed of travel by making use ofsegregated travelways. It highlights low−cost mass transit options − bus lanes, busway transit and light−railtransit − and attempts to assess their impact on transport users, transport operators and other beneficiaries inthe light of the experience of a few selected developing−country cities. The publication then outlines planningconsiderations that must precede investment decisions for the successful implementation of public transportsegregation schemes. Finally, a strategy for mass transit development is outlined for the benefit of urbantransport planners and decision makers.

The publication has been prepared as a part of the ongoing effort of UNCHS (Habitat) to promote thedevelopment of public transport in developing countries. It responds to the concerns expressed in Agenda 21,adopted by the United Nations Conference on Environment and Development, on the need for sustainabletransport strategies and actions as an integral component of the sustainable development of humansettlements.

We gratefully acknowledge the contribution of Mr. P.R. Fouracre of the Overseas Centre, Transport ResearchLaboratory (TRL), United Kingdom, in the preparation of this publication. The publication, without doubt, hasbenefitted from the findings of the research programme of TRL, funded by the Overseas DevelopmentAdministration.

The case studies have been contributed by Messrs T. Birgonul and H. Bayirtepe, both from the Middle EastTechnical University, Ankara, Turkey; by Mr. G.D. Esguerra, Director, Transportation Planning Service,Department of Transportation and Communications, the Philippines, and by Messrs L.A. Lindau and L.A. DosSantos Senna, both from the Federal University of Rio Grande do Sul, Porto Alegre, Brazil. Their contributionsare also gratefully acknowledged.

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Elizabeth DowdeswellUnder−Secretary−General

United Nations Centre for Human Settlements(Habitat)

I. TRAVELWAYS FOR PUBLIC TRANSPORT IN DEVELOPING COUNTRIES

A. Introduction

Public transport is a growth sector in most developing country cities. A World Bank estimate puts the numberof daily bus trips in 1980 at 600 million; this number is expected to double by the year 2000. Recent evidencefrom a limited number of cities suggests no change in this trend; bus passenger trips have been increasing ataverage rates of between 6 and 10 per cent per annum during the last decade.

The increasing demand for public transport is being driven largely by population growth. This growth not onlygenerates more trips, but with increasing city area, and hence longer trips, people become more dependenton public transport.

Personal motorized transport is still beyond the reach of the majority of the people, and increases in realincomes are still likely to encourage greater use of public transport as well as higher car−ownership levels.Indeed, in many African countries the economic down−turn has been reflected in static, or even decliningvehicle−ownership levels, which is likely to increase further the importance of public transport in larger cities.

Also contributing to the seemingly inexorable growth in demand for public transport are the locational patternsof the urban poor, resulting in a need to cater for long−distance commuting at low cost. Changing life−styles,more women in the labour force, and the youthful age structure of the society − all contribute to the increasingdemand for travel. To avoid public discontent, many countries maintain policies which actively encourage theuse of public transport through, for example, subsidized fare levels and significant fare−discounts for studentsand other privileged groups.

The growing awareness of the impact of transport on the environment and on the consumption of energy islikely to enhance further the policies oriented towards the promotion of public transport which allow themovement of people in a much more energy−efficient and less polluting manner than private motor vehicles.

As cities grow in size, increasing attention is required so attention focuses on the mass movement oftravellers along major transport corridors. Developing−country cities today have populations in excess of 15million, and these cities have to provide for 10−15 million public transport trips per day; corridor flows can bein excess of 1 million passengers per day. By the year 2000, there will be several more of these mega−cities,and many more "lesser" cities with populations greater than 5 million − over 40 according to one estimate.Coping with this scale of demand requires a high−capacity transit system. The recognized high−capacitysystems are suburban rail and metro. Suburban rail systems are important in only a handful of cities (forexample, Bombay and Calcutta), and can not be easily integrated into the existing urban physicaldevelopment structures. Metro systems can be sensibly justified, in economic terms, only in very specialconditions.

What is often overlooked in the development of mass−transit capability, however, is the potential of existingroad−based public transport and trams. In developing country cities, both are associated with poorproductivity, unreliability, long journey times and excessive over−loading. Seldom are they considered as"mass−transit" systems. Nevertheless, their performance can be substantially enhanced through the provisionof reserved travel space, with exclusive right−of−way. This provides two main benefits: it removes the vehiclefrom the interference of general traffic congestion, and it provides the basis for introducing additionaloperational measures which can further improve performance. The track also lends a certain degree of imageand permanence, which may be important in establishing the scheme with both users and land developers.

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Modern busway transit systems and light rapid transit (LRT −an advanced form of trams) operating on theirown track, can offer relatively high−capacity transit at moderate cost. These systems are likely to be able tocope with demands on many city corridors, and in the case of busways, have the added advantage that theycapitalize on the existing work−horse of urban transport.

Though busway transit has been successfully deployed in a number of developing−country cities, and indeedwas largely developed in the major Brazilian cities, it has not attracted the level of interest which its undoubtedadvantages merit. On the other hand, while there are few tram systems in use in the developing world (andindeed many were discontinued in recent times), LRT has attracted a good deal of interest. This may be,perhaps, because of its "high−technology" appeal or because it can be viewed as a worthy "second−best" to amore expensive metro. Environmental concern is another factor in raising that interest.

Clearly, buses and trams could contribute more to a city's mass−transit needs through the allocation ofreserved travel space for their operations. The purpose of this paper is to demonstrate this case fully and togive guidance on the conditions which would justify the dedication of road space for exclusive use of publictransport. It is not the intention to provide a detailed technical account and guidelines for implementation;these can be found elsewhere. This paper is targeted at decision−makers, agencies and planners who havethe role of developing and implementing city transport policy. In targeting this group, the aim is to sensitizethem fully to the concepts, opportunities and realities of these schemes. To some of this group, the idea thatbus and light rail are viable and attractive alternatives to heavy metro schemes, in many situations, may seemfanciful; but in an increasingly difficult operating environment, and with limited financial resources available,these projects may well offer the best direction for the development of mass transit.

The first section sets out the characteristics of city development which have an impact on transport and theway in which public transport has been made responsive to the growing demands placed on it. Prioritymeasures are then discussed with reference to specific case−study material; this draws attention to the typesof priority measure, the resources needed, the likely impacts, and the factors which are needed for success.This material is used to develop the general guiding principles for adopting priority measures, and a strategyfor promoting this policy within the structure of a city's development programme.

B. Characteristics of travel demand

1. Outline

To put the development of mass transit in some context, this section outlines the typical characteristics oftravel demand in developing−country cities. Daily trip rates per capita typically lie in the range 1.5−2.5.Because incomes are low, the majority of trips are undertaken on either some form of non−motorizedtransport (principally walking or by bicycle) or on one of the many forms of public transport. The latter isparticularly important in providing for longer trip lengths. Trips to or from work and education are likely to bethe majority of these non−walk trips. Work−trip movement is largely radial, focusing on the central area of amono−centric city. Third−world cities generally exhibit less distinct travel "peaks", possibly because of theinadequacy of transport facilities to handle demand, but also because mid−day commuting is common insome societies.

The main factors influencing travel demand include: city structure, socio−economic characteristics of thecommunity and transport facilities available to the traveller.

2. City structure

(a) Population

At the aggregate level, changes in population have three important effects on travel. First, more peoplegenerate more trips. This fundamental effect of population growth is important. It is estimated that eachadditional thousand people in a developing−country city is associated with an additional 350−400public−transport trips per day.

The second effect of population change concerns the development pattern of an urban area and the way inwhich the physical area of the city changes. Assuming there is no radical change in the city structure ordensity, more population implies expanding the city area and the likelihood of longer trip lengths. This hasimportant implications for modal choice. Increasing city size puts more pressure on public transport because

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travellers are unable to walk or cycle the longer distances involved.

The final major impact of population change concerns the way in which the transport system adapts to urbangrowth and affects travel patterns. As a city becomes larger, transport operators tend to concentrate theirresources on servicing general patterns of movement along major corridors, rather than trying to cater for allpossible origin−destination choices. These changes might" also be accompanied by a move away fromflexible public−transport services (like shared taxis) towards fixed−route bus services, often employinglarge−size vehicles. The result is more complex journeys, possibly involving interchange and lengthy walkingand waiting times.

Population growth appears to be slowing in the mega−cities of the developing world, though rates of 4 percent per annum are still common. The trend is still towards urbanization but, as in India, the growth seems tobe most pronounced in smaller cities, while larger cities are dispersing over a wider metropolitan area andbeyond.

(b) Urban form

A characteristic of many developing−country cities, even some of the very large, is their mono−centric spatialform. They may have retained this structure over time (and for much longer than their developed−countrycounterparts) partly because transport and other infrastructure is spatially concentrated and partly becausehigh−income residents, who might be expected to lead any move towards suburbanization, live close to thecity centre and have neither the incentive nor the opportunity to decentralize. The strong spatial concentrationof transport comes about because of limited resources; developing−country cities have a strong incentive toretain a compact, radial structure, which gives strong emphasis to low−cost public−transport corridors.Furthermore, a sizeable proportion of work−trips in most developing cities are focused on the city centre withits commercial, service, government and retailing activities. Some light industry may also be centrally located,though main industrial sites are likely to be in the suburbs.

The resulting impact on travel characteristics, particularly in medium to larger cities, has been the strongemphasis on radial movements towards the city centre. As an indication of the impact of city form on traveldemand, table 1 presents estimates of total corridor flows for different city size and structure. In this analysis,cities are categorized as having one of three basic forms: circular, semi−circular (where, for example, the cityabuts on to the sea), and linear. They are also sub−divided by spatial structure: mono−centric (single,dominant central focus), uniform poly−centric (with equal employment opportunities at both the centre and in anumber of surrounding sub−centres), and non−uniform poly−centric (where sub−centres exist, but the centredominates). For any given city size, corridor flows are highest in mono−centric cities.

Table 1. Estimated radial corridor loadings for different city forms

Population(millions)

Corridorlength(km)

Non−uniform, poly−centric: tripsper day (millions)

Uniform, poly−centric: tripsper day (millions)

Mono−centric:trips per day

(millions)Circular cities

>8 15.18 4.7−13.4 4.7−9.64.0−8.0 10.31 2.1−6.0 2.0−5.22.0−4.0 7.29 1.0−2.8 1.0−1.9 1.0−3.41.0−2.0 5.15 0.4−1.2 0.4−0.8 0.4−1.50.5−1.0 3.64 0.2−0.5 0.2−0.40 0.2−0.7

4.0−8.0 28.4 0.6−3.5 0.7−3.42.0−4.0 14.2 0.3−1.6 0.3−1.6 0.3−1.71.0−2.0 7.1 0.1−0.7 0.1−0.7 0.1−0.80.5−1.0 3.6 0.1−0.3 0.1−0.3 0.1−0.3

Income clearly affects the way in which people choose to travel. It sets the limit on their capacity to acquire apersonal vehicle and also, given that trip−making is relatively inelastic to income, it sets the limit on how muchof a particular mode they can "consume" in order to achieve their desired level of travel. For example, it isquite common for low−income commuters to switch their normal mode of travel from bus to walking towardsthe end of their pay−period as money runs out. It is not unusual to find that 10 per cent of household incomeis spent on transport; sometimes the figure is as high as 15 per cent. At this level of expenditure, per capitaincomes of between $US600 and $US1500 can just support fare levels of 20−50 cents for a typical round tripof 10 km.

4. Transport characteristics

(a) Infrastructure

There is little understanding of the impact of infrastructure provision on travel demand in developing−countrycities. There can be little doubt that new infrastructure will generate new demand, but the scale of the impactis unknown. New infrastructure and equipment may also enable concentration of peak travel, a possiblyunwelcome outcome!

One likely major impact of a large−scale investment in mass transit is that it will often emphasise andencourage existing travel patterns. This is because the investment is put in place to meet an existing highdemand which is expected to grow. Mass−transit lines constructed along main radial corridors will have thepotential to feed many more commuters into a city centre than an existing road−based system (i.e., with noreserved right−of−way). This has important implications for the development of the city structure; a radialmass−transit scheme may well petrify a mono−centric city−development pattern. Some cities have advocatedsuch schemes in a planned attempt to re−structure the city, but there are few examples of the successfulexploitation of transport in this way.

It is generally believed that the level of infrastructure provision in cities of developing countries' is lower than ina counterpart industrialized city. This contention would help explain the paradox that despite low vehicleownership in developing cities, congestion is as bad, if not worse, than that in developed cities which have farhigher vehicle−ownership levels.

(b) Public transport

Public transport is characterised in developing country cities by the wide range of vehicle types in use andservices on offer. Despite the variety of vehicle types it is clear that most are employed in one of two mainways: either providing a bus−like service with fixed routes and fares (for given trips) or a taxi−like servicewhere the route is determined by the hirer of the vehicle and the charge for the hire is metered or bargained.One important variation common in many cities is the shared taxi in which the first occupant determines thedestination and other passengers, heading in the same general direction, are picked up en route − eachpassenger paying a fixed fare. Most public transport is road−based and is likely to remain so in the future.

It has been noted earlier why public transport is likely to be important in any developing city and why itsimportance is likely to increase with city size. It has also been noted how the development of public transportmay influence city development; in summary a radial mass−transit system permits the city centre to develop.Continued dependence on more traditional public transport like cycle−rickshaws may also have some impacton city development, just as will the provision of cheap subsidized buses to low−income settlements at the cityedge.

Because of its importance in everyday life, public transport receives a good deal of attention from localgovernment. This usually takes the form of strong regulatory controls, particularly in respect of fare levels andsubsidies to public−sector operators. While some authorities have also invested vast sums on metro systems,few have introduced priority traffic measures for the main carrier: road−based public transport. Except onnewer metro systems, service quality on all forms of public transport is generally poor, partly because farelevels are insufficient to meet investment needs.

(c) Other modes

Walking, as a mode of transport, is limited in range by both its speed and energy requirement. Few trips ofmore than 5 km are made regularly. Even so, walking is a major mode of travel and can account for between20 and 40 per cent of trips, and even more if very short trips are included (travel surveys often exclude veryshort trips). Neither do these figures take account of walking associated with the use of other modes (i.e.,

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access to and from public transport etc.). The impact of walking on travel demand derives from the numbersof the population who are dependent on it; this group not only includes most housewives and children, butalso anyone who has to walk to access another mode. The limitations of walking are therefore very powerfulin the planning of the spatial location of local amenities, as well as the transport network.

In cities where bicycles are widely owned, their use is impressive; for example, in medium−sized Indian cities,cycles typically account for between 35 and 50 per cent of traffic on major corridors and 10 to 30 per cent ofall trips. However, the bicycle is nut in universal use in cities of developing countries and even where it is usedit may be barred, through social norm or male priority, to women riders (though not to women passengers).The bicycle extends the possible range of travel beyond the limits of walking to typically 10 km. Range isagain constrained by speed and energy requirement. Furthermore, as with walking, few cities activelyencourage cycling and its safety record is poor. Where the bicycle is common, it clearly has an impact ontravel patterns; principally it allows low−income male workers to commute from longer distances at very lowmarginal cost. In doing so, it frees these commuters from the more rigid radial patterns of movement whichare often imposed by public−transport networks.

While personal vehicle ownership is typically on levels several times lower than in the industrialized world,growth in the number of motor vehicle is high and congestion in large city centres is as bad as in anydeveloped city. Cars are mainly owned and operated by higher−income groups, though there is undoubtedly asubstantial fleet of company and government vehicles in use. The burgeoning middle−income groups are alsoacquiring cars or motor−cycles in increasing numbers. The impact of the private vehicle on the transportsystem seems to be immense, despite the fact that its share in modal choice is yet small. Most major urbantransport infrastructure projects are designed to ease the flow of road traffic, a large proportion of which ismade up of personal motor vehicles. Access to a motor vehicle confers a high degree of flexibility and rangein travel. In some cities, petrol prices are artificially low, encouraging excessive car use, while in others thehigh costs of operating a car may restrict its use to non−regular trips. Generally, however, without controls inits use, the growth in vehicle ownership must have an increasingly important impact on city development,possibly encouraging trends towards decentralization.

5. Summary

Cities in developing countries present a range of development characteristics, dynamic growth patterns,transport infrastructure and operations, and social customs which defy all but the broadest generalizations.Even so, it is important to try to understand the processes and interactions which drive transport demand iftransport planners are to contribute positively to the general debate about urban development.

As cities become larger travel demand grows at a disproportionately higher rate and there is a greaterdependence on public transport for travel needs, particularly from the urban poor. It is also evident that tripmovements become focused on corridor travel feeding into the city centre; once a city reaches a population ofabout 2−3 million, corridor flows will have reached around 20,000 passengers per hour per peak direction.Corridors and city centres which have to handle this level of demand are prone to endemic and prolongedtraffic congestion, because of the inadequate capacity of the infrastructure to meet both private and publicvehicular demands. Public transport, potentially the most efficient carrier and that which serves the majority oftravellers, cannot deliver an effective service in these conditions; journey times and waiting times are long,irregular and unreliable. Moreover, because of the poor productivity of buses, together with a low revenueearning potential, the financial position of operators is often weak. In these circumstances, the prospect forimproved public transport is grim; operators cannot afford new investment when they cannot even afford thedepreciation on existing stock.

From the traveller's viewpoint the main concerns are reasonable access to activities in reasonable time andcomfort, and at affordable cost. Even in the short term, transport planners and operators are struggling toachieve some semblance of satisfying these needs; and that at mounting cost as access to central area andcongestion problems worsen with increasing city size.

This situation can only get worse as cities grow and options for further infrastructure development are limitedby finance and environmental concerns. Ultimately, if the transport system cannot respond to these pressures,then other land−use developments may take control, leading to unstructured and diffuse city growth, and eventhe atrophy of the city centre. In order to sustain the growth of the city centre, and accommodate theassociated high volumes of corridor travel, consideration has to be given to the controlled use of theinfrastructure as a means of protecting the operations of public transport and hence making best use of limitedresources.

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C. Low−cost mass transit options

1. Perspective

Transitways are a means of controlling the use of road space so that public−transport vehicles are segregatedfrom general congested traffic conditions; one or more lanes of the road are reserved for the exclusive use ofpublic transport. These transitways can accommodate fixed−rail or road−based vehicles, having manysimilarities in design whichever vehicle type is used. The method of segregation can be either permanent −involving physical barriers, or open − relying on good driver behaviour and enforcement of segregation rules.The latter include traffic management measures to improve bus flow (e.g., bus lanes and bus gates); theseare prone to poor driver discipline and weak enforcement, and hence their effectiveness is not reliable.Physical separation of the travelway, because of its more permanent nature, provides more reliable protectionfor public−transport vehicles: it also provides opportunities to achieve a significant increase in the productivityof the public−transport vehicles using the travelway and hence to develop a low−cost, high−capacitymass−transit system.

In this section, the various options for travelways are described, starting with basic priority measures and thenfocusing on the physically segregated schemes (busway transit and LRT). Busway transit is a particulardevelopment of bus−priority measures, which seek to optimize the output of bus technology through bothinfrastructure investment and improved operational procedures; in many instances it will require no substantialinvestment in equipment, since buses are in wide current use. LRT and other fixed−rail "light" systems are notcommon in the developing world, and any investment scheme is likely to require a complete package ofinfrastructure and equipment. Even where LRT systems are in use in developing countries, the equipment islargely antiquated and of little value to a modern system. Inevitably, investment in LRT will be at a higher levelthan in a busway transit system.

Before describing the options in detail, their general specifications are briefly compared with that of a typicalheavy−rail mass−transit system. Table 2 sets out some key points of comparison. Here, separate columns aregiven for trams and LRT. on the grounds that they can be distinguished by the amount of sharing of theirright−of−way with other traffic and, hence, there can be differences in specification, operation andperformance. However, there are no hard−and−fast rules to distinguish at what point a tram becomes an LRT,and for the most part this paper will treat them as similar types of transit system.

Table 2. Main characteristics of mass−transit options

Busway transit Trams LRT MetroRight−of−way Physically

segregated alongkey stretches

Mainly sharedwith roadtraffic

Physically segregated alongmuch of route; somegrade−separated junctions

Fully grade−separated

Av speed(km/h)

20−25 10−20 20−30 30−40

Signalling Visual, with somesignals

Visual, withsome signals

Visual plus signals Automated

Platforms Low level Low level Low and medium level High levelPass. Transfer(per hour)

What will be clear from table 2 is that with the exception of the impact on the environment, there is little tochoose between LRT and busway transit; both have medium capacity and can operate at speeds in excess of20 km/h. Some authorities argue that busway transit can only achieve these levels of output during shortperiods, i.e., they cannot perform as consistently highly as LRT. This cannot be fully substantiated as thecase−study material will reveal. The table also illustrates how performance is affected by the level of sharingrights−of−way with other traffic and the spacing between stops; quite clearly, full segregation and long spacingbetween stations, confers on the metro the advantages of high speed and use of high−capacity cars in largetrain formations. There are a few examples of fully segregated LRT (notably in Manila), but no knownexamples of a fully segregated busway transit system. It can only be speculated that the capacity of asegregated busway system would be in excess of 30,000 passengers per hour per direction.

2. Bus lanes and other bus−priority measures

The main feature of bus−priority schemes is the separation of buses from other traffic (either at selectedlocations, like bus−stops, or along running sections) through the use of "paint and signs" which indicate therules of segregation. Bus priority measures critically depend for their effectiveness on disciplined driverbehaviour, backed up as necessary by strong police enforcement.

Junction−related delays can be dealt with by spot priorities, examples of which are turn−ban exemptions andbus gates. Turn−ban exemptions permit buses to turn out of a particular road, where this movement is bannedto other traffic. Bus gates (see plate 1) permit buses to turn into a particular road, where this movement isbanned to other traffic. Short bus−lane sections at junction approaches can allow buses to "queue−jump" andbus−activated traffic−signal pre−emption can reduce delays. However, while spot priorities are a useful trafficmanagement measure, they cannot by themselves improve bus performance over whole routes.

Painted bus lanes can give buses priority over long sections, provided they are respected. There are two maintypes of bus lane: with−flow (see plate 2) and contra−flow (see plate 3). In environments where road−userdiscipline is poor, and police enforcement is weak, with−flow lanes tend to be violated and are relativelyineffective; the effects of a bus−lane scheme implemented in 1989 in Manila fall short of expectations forthese reasons. In contrast, contra−flow bus lanes tend to be self−enforcing, since buses travel in the oppositedirection to other vehicles. However, there are some indications that pedestrian/bus accident rates may behigher along contra−flow than along with−flow bus lanes, because pedestrians are unaccustomed to looking"the wrong way". With−flow bus−lanes can be constantly operated or only in specified hours when thedemand for public transport is high. While the latter way of operation allows better use of road space in theoff−peak hours, it may make the enforcement of road−user discipline more difficult.

Plate 1. A bus gate providing buses with unhindered access to a main road: Hong Kong

A traffic scheme may include both with−flow and contra−flow lanes, as well as spot priorities. Although onelane is usually provided in each direction for buses, two lanes may be provided where bus volumes are high,at busy bus stops (to allow buses to overtake one another) or on long uphill sections.

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3. Busway transit

(a) Outline

The traffic violations experienced by with−flow bus lanes can be overcome by physically segregating busesfrom other traffic by means of studs, kerbs or fences. A distinction is made between a bus lane and a buswayas follows:

− A bus lane is essentially a "paint−and−sign" scheme where buses are separated from othertraffic by road markings or separators, which dissuade but physically permit crossing by bothbuses and general traffic.

− A busway involves construction where schemes may be partially physically segregated fromother traffic, for example in the vicinity of bus stops (e.g., by means of island stops) or may befully segregated from other traffic by kerbs or fences.

Plate 2. With−flow bus lane: Bangkok

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Plate 3. Contra−flow bus lane: Bangkok

A busway may be implemented as a traffic−management measure, without complementary improvements tobus operations and management, but busway transit involves a package of such measures with the generalaim of promoting high output. Thus busway transit includes a right−of−way for the exclusive use of buses, withat least one section of busway and some additional features like well−designed bus stops, special operatingmethods (bus convoys or express operations) and efficient fare collection methods. Clearly defined routeswith name's like "green line" or "circle line" can add to the image of the service.

The earliest busway transit schemes were introduced in Europe in the early 1970s hut in the late 1970s andearly 1980s a series of innovative busways was implemented in various Brazilian cities, many with the WorldBank encouragement and assistance. Other examples of busways in developing cities are in Abidjan, Ankara,Santafé de Bogotà, Istanbul, and Lima; plans exist for others in Bangkok. Jakarta. Karachi, Nairobi andShanghai. Other bus−priority schemes (with−flow and contra−flow bus lanes, bus−only streets and spotimprovements) were also implemented in many cities. While some schemes were very effective many wereineffective due to enforcement difficulties and poor design.

(b) Special operational measures

A basic busway, comprising one lane for buses in each direction is essentially a traffic engineering measure.Its main shortcoming is that a bus boarding at a bus stop or a break−down bus delay the operation of otherbuses on the busway as overtaking is possible only by using the lane for traffic running in the oppositedirection. However, performance of this basic busway can be enhanced substantially by adopting variousspecial operational measures in order to form a "busway transit system" (see table 3).

Table 3. Special operational measures

Busway transit = Busway infrastructure + Special operation measures

Special operational measures include:

• bus overtaking facilities at stops;• trunk−and−feeder operations;• bus ordering (placing buses in the correct order at the beginning of a section);• high−capacity buses (e.g. articulated or double−deck)• off−board ticketing;• traffic signal techniques to give buses priority at intersections;• bus dwell time management (to eliminate excessive delays at very busy bus stops); and• guidance systems (e.g. O−Bahn).

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Where passenger demands are high, the provision of facilities to permit buses to overtake one another at busstops can increase throughput and commercial speed considerably (see plate 4). This is because buscongestion is reduced and buses are no longer "trapped" behind one another in a single lane (as occurs withtrams or light rail vehicles).

Trunk−and−feeder operations also offer good performance. In this system, feeder buses collect passengersand bring them to a transfer terminal, where they transfer to line−haul buses; some systems allow transferwithout payment of an additional fare.

Plate 4. Busway transit stop, with overtaking facility: São Paulo

Early work in Brazil led to the development of a high−capacity bus convoy scheme (COMONOR), in whichbuses were assembled at the beginning of a section in the order in which they would stop (rather like a train).Although not joined together, the buses started and stopped broadly in unison. Although initially successful,COMONOR was found to be too difficult to sustain. The system evolved into 'bus ordering" in which buses areallocated to one of three groups (A, B, or C). The buses arrive in random order at the beginning of a sectionand are marshalled into the preferred sequence, although not into strict convoys. This method operateseffectively and can improve commercial speeds at high levels of passenger demand.

Line−haul capacity can be enhanced by the use of high−capacity buses, whether articulated, double−deck orwith the use of bus−plus−trailer combination. However, passenger transfer capacity at bus stops is often theconstraint on system performance, and door configurations and ticketing arrangements are often moreimportant than bus capacity per se.

Bus delays at bus stops can be minimized by collecting fares and issuing tickets prior to passenger boarding.Through−ticketing of the type adopted in Curitiba (trunk−and−feeder buses) and São Paulo (bus−metrotickets) also contribute to reduced boarding times. At bus stops where passenger volumes are very high,excessive bus dwell times can occur when too many passengers try to board incoming buses and block thedoorways so that the doors cannot be shut. This problem can be minimized by assigning staff to controlboarding.

(c) Current usage of busway transit

More than 40 busways exist throughout the world; many of these are in Brazil, where both Curitiba and PortoAlegre have five busway corridors of aggregate lengths 53.7 and 27.5 km respectively. Examples of individualbusway transit schemes in cities of developing countries are shown in table 4. It should be remembered thatthe length of the busway relates to the section of reserved track, and not the route length over which busesusing the busway are operated.

(d) Bus design

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The busways included in table 4 use mainly standard diesel−engined vehicles of 10−12m length with acapacity of 50−80 spaces (90−100 in crush conditions). In São Paulo, the busways also operate withdouble−deck and trolley buses. There is no known example of a busway which permits the operation of smallvehicles, and, in general, the larger the bus used on the busway, the higher the capacity of the busway.However, there are limiting factors to this generalization: the number of exit/entry points to the bus is limited totwo and possibly three doors (perhaps six in the special case of a bus−trailer combination), whatever itscapacity; large capacity double−deck vehicles can encounter exit delays from the upper deck. Another limitingfactor on most current bus designs is the floor height, which tends to restrict ease of access and egress.

Bus design is changing in an attempt to improve on the problems of boarding and alighting. In one designdirection manufacturers are producing buses with low floors; another innovation from Brazil, however, is toprovide high platform access to specially modified standard buses which have wide metro−like access (seeplate 5).

Table 4. Examples of busway transit in cities of developing countries

Location Length(km)

Average stopspacing (m)

Average junctionspacing (m)

Special features Annualpassengers

(millions)Abidjan: Blvd. de laRepublique

1.27 400 160 none 95

Ankara: Besevler−Dikimevi 3.6 310 410 none 35Belo Horizonte: Av.Cristiano Machado

8.57 610 920 overtaking at stops 80

Curitiba: Eixo Sul 9.5 430 430 trunk and feeder 45Istanbul:Taksim−Zincirlikuyu

2.27 310 410 none 55

Porto Alegre: Assis Brasil 4.5 580 410 bus ordering 130Farrapos 2.8 560 390 bus ordering 85São Paulo: Av. 9 deJulho/S. Amaro

7.9 600 530 bus ordering andovertaking at stops

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(e) Design of busways

Busway track may be located along an existing or a new right−of−way. For an existing right−of−way, the bustrack may be located in the centre of the road (median; see plate 6) or along the sides (lateral; see plate 7).Purpose−built busways can comprise a dedicated at−grade bus road, a dedicated right−of−way along a newroad or an elevated busway.

Plate 5. Raised bus stands for faster boarding and alighting of bus passengers: Curitiba

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Most busway transit schemes are physically segregated from other traffic along their entire length using kerbs,fences or heavy studs; a few have segregation only at island bus stops.

Plate 6. Median busway using the central reserve of a dual carriageway: São Paulo

Plate 7. Lateral busway using one half of dual carriageway: Istanbul

In order to minimize disruption to busway operations, the number of roads crossing the busway is usuallylimited to main thoroughfares only. Kerbs or barriers may be placed to prevent traffic turning across thebusway into or out of minor side roads. In such cases, side−road traffic is restricted to right turn in/right turnout (right−hand rule of the road) and "Q" and "G" turns are used to concentrate traffic on to a limited numberof cross routes. Such arrangements have an impact on local access to adjacent properties, which needs to beconsidered very carefully.

Bus stops are an important component of busway−transit design and operations; delays can occur due to theinterference of buses with one another, and due to interference between passengers awaiting different buses,as well as the time lost in boarding and alighting. Some very busy bus stops must be designed to handle inexcess of 300 buses per hour and 5000 passengers per hour. To accommodate such numbers requires longbus−stop areas, facilities for overtaking, with possible use of parallel bus bays. All bus stops are low levelwhich incurs additional time penalties for boarding and alighting passengers who have to negotiate the bus

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steps. As noted above, modem buses with low−level floors improve the problem, as does providing as manyaccess doors on the vehicle as is practicable.

A high degree of traffic signal control is generally required in order to manage high bus and general trafficvolumes, without excessive delays. However, where bus flows are high, there is a "constant" call for greensignal time by buses and selective−detection of buses may not be appropriate. Signal control can be used toaid bus movements in the following ways:

− Selective detection of buses to extend a green phase or to recall a green phase;

− Demand dependent stages (which enables a bus to call a stage which would not otherwiseoccur);

− Signal time biassing to favour a stream with a high proportion of high−priority vehicles;

− "Gating" in order to manage queues in favour of high priority vehicles.

It is important to organize suitable collector and distributor systems to feed buses on to the busway and topermit them to leave the busway, without undue congestion. The capacity of the collector and distributorsystems should at least match the bus demand at the relevant locations. This can be difficult where one ormore busways lead into a city centre; in such cases, special arrangements are needed to disperse high busvolumes into terminals or into a circulation system comprising bus roads or lanes. The use of a range of buspriority techniques in and around a city centre will usually be essential to enable a busway to functioneffectively. Where enforcement is expected to be a particular problem, due to poor road−user discipline,physical and electronic measures are available to dissuade other vehicles from entering the busway.

(f) Guided busways

A "guided busway" is simply a transitway equipped with a guidance mechanism (tracks) which physicallyguides the bus enabling it to travel at speed in a relatively narrow right−of−way. The prime advantages of aguided busway compared with a conventional busway are:

− The track provides a permanent physical presence, which makes the system more "visible"to politicians and public alike;

− Where the right−of−way is severely constrained, or land values are high, guided buses canoperate at high speed in a right−of−way about 1 metre narrower than that of a conventionalbusway; however, this advantage is lost at junctions (where capacity is usually critical) in thecase of guidance systems which require an entry splay;

− The track "occupies" the right−of−way and makes violation by other vehicles extremelyunlikely.

The prime disadvantages are the additional cost compared with a conventional busway and the severanceeffect in urban areas. It appears that the prime locations for guided busways would be in suburban areasrequiring high−speed operations. A guided busway can offer broadly equivalent levels of service to LRT, butat much lower capital cost. It also has the advantage over LRT that the vehicles can leave the track and sooffer door−to−door service over a wide catchment area, without enforced passenger interchange.

(g) Busway transit performance

The practical capacity of busway transit for various design characteristics are summarized in table 5. Theseestimates are based on surveys of the performance of existing busways, which use standard or highercapacity buses. It may be concluded that well−designed and efficiently run busway transit systems canachieve consistent flows of 25,000 pass/hour per direction, at speeds of up to 25 km/hour.

4. Light−rail transit

(a) Outline

As the term implies, LRT usually employs vehicles and track construction which are less substantial than a fullmetro. Some systems, including those in Manila and Istanbul, use lightweight vehicles on a system which has

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an exclusive track and high platforms similar to many metros. Trams are a basic form of LRT which havelimited rights−of−way over most of their route, sharing roadspace with ordinary traffic. Trams were firstintroduced in 1832 in the United States of America to overcome the poor road conditions experienced byhorse−drawn buses. This led to an improvement in ride quality, due to the use of steel rails; furthermore,because of the reduced friction, one horse was able to pull more passengers. Thus the tram was able toattract more passengers, and carry them more cheaply than horse−drawn omnibuses.

Table 5. Measured and estimated busway performance

Description Example Measured peak hour flow:passengers per hour per direction.

Estimatedpractical capacity:passengers perhour.

Basic busway − no options Ankara, Istanbul,Abidjan

7,300− 19,500 5,800− 18,100

Trunk−and−feeder Curitiba 9,900 13,900−24,100Bus ordering Porto Alegre 17,500− 18,300 8,200− 14,700Overtaking + express services Belo Horizonte São

Paulo15,800−20,300 14,900−27,900

Optimum combination ofhigh−capacity options

None − 30,600

Electric traction became practical around the turn of the century and encouraged further investment growth ina very short time. However, the great advances in automobile technology in the early part of the twentiethcentury led to bus design improvements which were not matched in the tram industry. The tram began to beseen as a down−market form of transport. Although still important for mass transport of low−income earners,its role was under attack; trams were seen as obsolete, and a cause of congestion. The onset of cheap dieselfuel, and the greater flexibility of bus technology saw the demise of many tram systems. In more recent times,however, some city authorities have taken a fresh view of trams and LRT. In post−war Germany, and morerecently in France, a desire to reduce imported fuel consumption has been used to promote light rail. Mostrecently the issue of environmental protection has played a significant part in decisions to build LRT in NorthAmerican cities.

(b) Current use of LRT

Worldwide, there are more than 150 tram or LRT systems in use; the majority are concentrated in Europe andNorth America. Most systems (90 per cent) carry fewer than 20 million passengers per line per annum; theintensity of use of each line is typically below 2 million passengers per km per annum. Few developing countrycities have a tram or LRT system. Those that do are listed in table 6. Two of these systems (Manila andIstanbul) have grade−separated track and sophisticated signalling and control; the remainder are largely tramsystems (see plates 8 and 9) with some sections (extensive in the case of Tunis and Cairo's Heliopolis andAlexandria's Ramel networks) of reserved track. All systems use lightweight cars, however.

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Plate 8. Two−car tram set of Cairo Transport Authority.

Plate 9. Veteran trams still used in Hong Kong

(c) Design of LRT

Trams and LRT usually run on standard gauge track (1435mm); in the case of street operation, the rails lieflush with the road surface. Where the track is segregated from other road traffic, the tracks may be raisedand laid on ballast, which allows for ease of maintenance. One of the characteristics of LRT whichdistinguishes it from a metro is that the minimum radius of curvature can be as low as 10m (though morecommonly 20m), which allows the planning of systems in tight and sinuous rights−of−way. LRT can also workon steeper gradients (up to 8 per cent) than heavy−metro systems.

As with busway track, an LRT track can have a lateral or median position within the road alignment. Thetransit−way can be delineated by "paint−and−sign" or by physical barriers like curbs, fences or studs. In thecase of a median position of the track, special provision must be made for boarding and alighting passengers,who may have to cross the path of on−coming traffic to access the tram. In a few cities, the concept of ashared transit−way for both bus and LRT has been tried at special locations (bridges, tunnels and passengerstopping points); this requires a greater than minimum distance between tracks to accommodate the lessprecise nature of bus driving.

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Table 6. LRT and tram systems in cities of developing countries

City Population(millions)

Network length(km)

Number oflines

Passengers carried per annum(millions)

Alexandria: 3.5Ramel 15.0 6 118Madina 28.0 17 137

Anchan 1.2 12.9 1 81Ascuncion 0.5 5.0 1 1.6Cairo: 12.0

Heliopolis 16.0 7CTA 54.0 16 141

Calcutta 10.0 71.0 29 173CampinasChangchun 1.8 20.0 3 105Dalian 1.5 14.7 3 180GuadalajaraIstanbul 5.8 7.0 1Manila 8.0 15.0 1 90Mexico City 18.0 41.0 2 17MonterreyRio deJaneiro

10.2 8.2 2 3

Tunis 1.4 40.0 4Rolling stock is lightweight and usually powered by electric traction from overhead supply. The cars areoperated singly or in trains consisting of two or three cars. Tram cars have 4− or 6−axles, while LRT maytypically have articulated 6− or 8−axle cars, or multiple−unit trains of 4− or 6−axle cars, or two 8−axle cars.Passenger loads can vary from 100/180 in tram cars to 250 in a modern LRT car.

Again, as with busway transit, delays to LRT can be critical at junctions. Similar methods of giving priority areused: limiting the number of crossing roads; eliminating right−turning (or left−turning for right−hand drive)traffic across the path of the tram; signal actuation by approaching trams; special signal phases for trams.Grade−separation may be required at very busy junctions.

Trams are most likely to have low−level access (like buses) while modern LRT may well be designed foraccess from raised platforms. Some modem LRT cars have low floors which improve low−level access.Delays at tram stops are minimized by providing several wide access doors for each car. In the nature of afixed−rail system, however, there is no possibility of one tram overtaking another. Delays to LRT vehicles canbecome cumulative, causing large irregularities in arrivals. (Headways of 16 min. have been recorded incase−study systems having a nominal 3 min. headway.) This leads to further delays as passengers blockdoors whilst empty following trains wait to access the station.

Most LRT will be operated under manual vehicle control, i.e., within the visual capabilities and judgement ofthe driver. The driver can close−follow a preceding vehicle, and headways can be very low (though speedsare correspondingly low). Some high−technology LRT schemes, in particular grade−separated, will be rununder some form of automatic train protection. This involves a sophisticated signalling system which controlsthe spacing between successive trains.

(d) LRT performance

There is little recorded information on passenger handling performance of LRT systems. Pre−war Austrianand German streetcar systems were recorded as carrying between 20,000 and 25,000 passengers per hourper direction; but this was under exceptional circumstances of excessive over−crowding, slow speed andabsence of much competing road traffic. More typical for street−cars are the figures shown in table 7, whichrecords information for developing−country systems. The Cairo CTA tram network has about 10 per cent of itslength protected from other traffic, whereas the Alexandria El−Raml network has 80 per cent protection.

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Table 7. Measured LRT performance in cities of developing countries

Description Examples Measured peak hour flow: passengers per hour perdirection.

Street−car: low protection Cairo−CTA 2,300high protection Alexandria

El−Raml11,600

LRT: high protection Tunis 9,300grade separation Manila/ Istanbul 25,000

The LRT networks carry more passengers. In Tunis the majority of track is protected (see plate 10), and tramshave priority control over signals at the at−grade intersections. In Manila, the complete track isgrade−separated (see plate 11), and the performance of the system is correspondingly high.

5. Costs of the systems

(a) Capital costs

Out−turn cost data for existing travelway schemes vary according to design standards, constructionprocedures, initial condition of the roadway, local inflation rates, exchange rate variations, and so on. Table 8presents investment cost ranges for the main infrastructure and equipment components of the mass−transitoptions. For comparative purposes, the equivalent cost ranges for heavy metro are included. Many of theinfrastructure costs (particularly the labour component) can be contained within the domestic economy, butthe cars, power and control equipment may well involve significant expenditure of foreign exchange. LRT andtram systems will incur higher off−shore costs than busway transit, and may also need additional training andimplementation programmes which depend on continuing foreign technical assistance and associated foreignexchange outflow.

Plate 10. The new LRT in Tunis

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Plate 11. Manila's elevated light rail transit system

Table 8. Travelway equipment and infrastructure costs (after Armstrong−Wright, 1986)

(costs in $US millions, 1993 prices)Busway transit Tram LRT Metro

Rolling stock:−standard bus 0.12 per bus−double−deck bus 0.15 per bus−articulated bus 0.20 per bus−tram car 0.45−LRT car per car 1.2 per car−metro car 1.5 per carElevated structure 20 per km 20.0 per km 30.0−60.0 per km 30.0−60.0 per kmTunnel 90.0−135.0 per km 90.0−135.0 per kmSegregated way 1.0−2.0 per km 1.0−2.0 per km 3.0−10.0 per kmTrack 1.5−3.0 per km 1.5−3.0 per km 1.5−3.0 per kmSignals 0.02 per junctiona 0.02 per junctiona 0.5−1.5 per km 1.5−7.5 per kmPower supply 3.75−4.5 per km 3.75−5.0 per km 1.5−4.5 per kmStations/stops−surface

− The existing road pavement would be adequate except in the transit stop area, wherecomplete reconstruction would be required;

− No extensive diversion of public utilities would be required.

Providing guidelines for the cost of an elevated structure poses greater difficulties than for an at−gradetravelway, due to the wide range of possible construction techniques, foundation conditions, bus stoptreatments and other features. There is little direct experience of the cost of elevated busways since noextensive sections have been constructed, although several are under consideration. Based on Britishconditions, a representative elevated travelway for buses or trams is estimated to cost of the order of $US20million per km (1993 values). Elevation need only be necessary where traffic capacity at selected junctions iscritical. Clearly if transit stops can be accommodated at−grade, considerable cost savings are possible.

The costs of associated infrastructure will vary from place to place and will depend on local requirements. Thecost of a footbridge might typically be in the order of $US80−100,000. Where a new and comprehensivetransit system is to be implemented, new depot and workshop facilities will be required; this is certainly thecase for rail schemes and will also be the case for busways where a purpose fleet is acquired. Again, costsdepend upon many local factors, but a new depot for about 200 buses (or 100 tram cars) could cost in theregion of $US6−8 million excluding land costs. A workshop and central stores facility might cost a similar sum,depending upon the scale of facilities required.

If a trunk−and−feeder system is to be operated, transfer terminals will be needed along the main axestogether with a terminal station at the end of each corridor. Costs depend upon many local factors, includingstandards, but could be of the order of $US0.5 million for a basic transfer station and $US0.8 million for abasic terminal station excluding land costs. Terminals may offer development opportunities and additionalsources of revenue.

The overall capital costs for a complete system are estimated in table 9. The more grade−separation,tunnelling, use of heavy rolling stock and sophisticated control equipment, the higher the cost.

Table 9. Capital costs of mass transit schemes

(Costs in $US millions (1993 prices))Bus lane Busway transit Tram LRT Metro

Capital cost per route km.

Little is known of the financial performance of low−cost mass−transit schemes. In the case of busways, thescheme's performance is usually subsumed within the total financial performance of the participating buscompany; neither would it be normal for the capital costs of the track to be included in bus company accounts.Tram and LRT schemes fall into two groups: those which are well−established systems using old technology(like Cairo and Calcutta) and the newly−established systems using modern equipment (like Manila and Tunis).The financial performance of the old systems is generally poor. As an example, the Calcutta TramwayCompany could only cover about 40 per cent of its operating costs exclusive of depreciation and interest. Themodem systems present a better picture. For example, the Manila LRT is able to cover its direct operatingcosts; however, it makes only a small contribution to interest charges and loan repayment much of which is inforeign currency which has appreciated against the national currency.

Very few public−sector bus or rail services, if any, are able to rely entirely on direct revenue. An examinationby the World Bank of 20 representative public−sector bus operators revealed that on average only 62 per centof total costs (operating costs, depreciation and interest) was recovered from fare−box revenue and otherdirect income. For urban railways the figure is even lower and generally in the region of 30 per cent.

Private−sector bus operators (who service the majority of bus networks) are usually able to survive onfare−box revenue alone; an examination by the World Bank of 33 large representative cities found thatfare−box revenue was, in effect, the sole source of funding for over 75 per cent of bus and minibus trips. Thefunding of bus services solely by users is possible because the majority of users accept a low standard ofcomfort and safety in travel, and labour costs of bus operation are low.

6. Summary

The great advantage of busway transit, in particular over metros, is in its flexibility: the ability to changealignments relatively quickly in response to changing demands; the ability to implement progressively asdemand increases or as funds become available; the ability to implement piecemeal projects in key areas andthe ability to penetrate development, not necessarily where the main right−of−way exists. Perhaps mostimportant of all, the development of busway transit builds on the city's existing wealth of experience in busoperations. One of the main disadvantages of busway transit, however, is that its implementation requires theactive cooperation of the highway authority, the licensing authorities, the police and bus operators. Suchcooperation can be difficult to achieve.

LRT and tram systems are more expensive to construct than busway transit, particularly where the latter doesnot include the acquisition of a new bus fleet. The great advantages of a modern rail system over buswaytransit is in their image and general environmental "friendliness". Image is clearly important to decisionmakers and there is little doubt that it would weigh heavily in a straight choice between the two. The image ofa busway transit system could be improved if the bus fleet was modernized and given a special livery; butusually the bus is cast in the role of the traditional and somewhat hackneyed transport, which has little to offerthe modern world. LRT is seen as an example of modern technology which can contribute to civic prestige; itinvites political support as a high−profile gesture towards tackling urban transport problems. The greatdisadvantage of trams are their inflexibility (in route network) and the need to provide a complete track systembefore trams can be operated.

D. The impact of public transport segregation

1. The users

The majority of beneficiaries of busway transit in cities of developing countries are likely to be the users ofexisting public transport. In the industrialized world, there has been no evidence of any major switching to busfrom private modes, as a result of the introduction of priority measures. The evidence for switching to LRT isless clear; it is known, however, that the patronage of metros in the developing countries has been drawnalmost exclusively from the users of existing public transport, or through new trip generation effects. There arestrong conceptual grounds for believing that most users of private vehicles in developing−country cities areunlikely to be attracted to the use of public transport; these travellers come mainly from high−income groups,who will value comfort and convenience of personal transport very highly.

Generation effects may be substantial; for a number of schemes in industrialized countries, generated travelhas constituted over 15 per cent of patronage, and typically the new transit scheme has contributed to a 3 percent per annum growth in use of public transport.

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Many earlier studies have attested to the level of user benefits which result from bus−priority measures.Typical time gains in European and North American cities, measured over the length of the scheme, rangebetween 20 and 50 per cent. Similar observations have also been noted in Singapore, Bangkok and PortoAlegre; in the latter, journey times were reduced by 29 per cent. Small improvements in regularity have alsobeen noted and there should be some improvement in the quality of travel, particularly if the investmentincludes new rolling stock which is clean and comfortable.

2. Transport operators

Very little quantitative work seems to have been done to assess how bus operators benefit from bus−priorityschemes. The benefits are likely to occur either through reduced fleet size required to service a route with thesame headway, improved output per unit of cost and reductions in operating costs which are speed−related.While it is known that bus speeds have been improved as a result of building busways (for example, by over40 per cent along the bus corridors of Porto Alegre), the corresponding improvement in bus output andoperating costs is not known. In Belo Horizonte, bus fuel consumption was reduced by almost 20 per cent asa result of using busways, but this is an isolated case of reporting. Even so, it should be assumed that busand tram operators must benefit to some degree from the enhanced operating environment brought about byprovision of travelways.

Where frequency and reliability in the service is improved, in response to the priority scheme, new passengertrips may be generated. It is also conceivable that a busway scheme may generate opportunities for scaleeconomies which might not otherwise be feasible (e.g. use of high−capacity vehicles).

3. Non−users

The impact of bus−priority schemes on other road users could negate the value of the scheme, and there isno doubt that user savings have been outweighed by non−user disbenefits for some bus−lane projects. This isusually traceable to some technical design feature which could be modified, or to the fact that bus flows aretoo low. It is likely that bus flows in excess of 60 per hour (or public−transport passenger flows in excess of10,000 per hour) could always warrant a reserved track. Interestingly, in both Singapore and Bangkok theimprovements in bus speeds, resulting from bus−priority schemes, were complemented by improvements inthe speed of other traffic, a pattern which can probably be attributed to improved driver behaviour resultingfrom the segregation of vehicles with widely differing characteristics.

Travelways are often promoted on the basis that they can contribute to relief of city−centre traffic congestionthrough encouraging a modal switch from private to public transport. The evidence for success in thisobjective is, unhappily, not strong; most users of new modes have changed from another transit mode (or inthe case of busways, their bus simply switches from an unreserved to a reserved track within the sameright−of−way). In cases of some rail−transit schemes this change has been forced on the traveller through theelimination of existing transit services to protect the new system. Even where there may have been a switchfrom private to public transport, the improved traffic conditions on the road network will quickly induce new cartraffic to emerge.

However, there are reasonable grounds for supposing that travelways could have some influence on thespread of traffic congestion. With increasing car ownership and use, city−centre traffic congestion reacheswhat has been described as the threshold of the intolerable; it cannot get any worse, and assuming alltraffic−engineering measures have been exhausted, can only spread more widely, rather than more deeply.New roads to access the city centre may improve the situation, but there are limits to what can be achieved,simply because the land is not available and the resulting environmental damage is likely to be too great. Amass−transit system, making the best use of the existing road system, provides the capacity needed toaccess the city centre, without the associated penalties of road building. In providing greater access, themass−transit system helps to reduce the spread of traffic congestion. In particular, the improvement of publictransport can make the restraints of the use of private−motor vehicles more politically acceptable, and suchrestraints may become necessary as well for arresting congestion as for environmental reasons.

However, the environmental impact of public−transport segregation will require also detailed assessment inthe light of scheme characteristics and local circumstances. Travelways, by their nature, provide ahigh−speed track in built−up areas where pedestrian activity will be intense. The resulting severance, safety,noise and air−pollution effects all warrant particular attention. Severance effects can be minimized, and safetyenhanced, by suitable urban design and by the provision of adequate pedestrian−crossing facilities. Sometravelways have been designed so as to minimize the interaction of pedestrians and vehicles; butpedestrian−crossing points are inevitably necessary (if only to access the travelway), as is interaction with

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other traffic at grade junctions and along unprotected rights−of−way. Evidence from transit schemes inindustrialized countries suggests that accident rates per vehicle−km on light rail are a little higher than thosefor buses, but on a passenger−km basis light rail is generally safer than buses. On−street noise andair−pollution effects of busway transit can be minimized through the use of modem, LPG (liquid petroleumgas)− or CNG (compressed natural gas)−powered buses, or electric−powered trolleybuses.

4. Urban development

The essence of a city centre is that it is the most accessible point from both within and without the city. Thissuperior accessibility is important for many activities, and in particular for those central functions which servea wide area and/or need a wide labour market: head offices, central government offices and legal institutions,financial institutions, media firms, theatres, department stores etc. and all the supporting organizations(catering, hotels etc.) that exist to serve these central functions. The fortunes of the city centre are at risk if thepublic−transport system proves inadequate in supporting these central functions. This is because the vastmajority of commuters to any big city centre depend almost exclusively on road−based public transport foraccess. If the city centre becomes congested, then its relative accessibility may suffer, because thepublic−transport system cannot perform effectively. As a result, new central functions will be discouraged fromlocating in the city centre and old established ones may start to drift away. Clearly, there is an intimate andvital relationship between the well−being of the city centre and its public−transport system which should neverbe overlooked. For this reason, it is becoming increasingly apparent that the development of urban transportin the major cities may be reaching a stage where priorities have to be imposed, and mode choice has to bemanaged to the advantage of public−transport systems. Once the limited supply of road space feeding the citycentre is exhausted, the only possible relief would seem to be through the development of a mass−transitsystem which makes best use of the available road space.

Apart from promoting the performance of public transport, and thereby contributing to the healthy growth ofthe city, travelways may have their own intrinsic developmental impact on a city. Mass−transit schemes havesometimes been proposed to enhance or encourage new city development and/or renewal. For example, it isreported that the development of the LRT in Manila has played a key role in shaping the urban developmentof the metropolis, triggering the redevelopment of the traditional centres of business and trade, andencouraging commercial growth along its route. this impact of travelways is not fully understood and has notalways worked, in particular where planning controls on urban development are weak. Generally, if a city hasa buoyant economy then a mass−transit system can contribute to and accentuate that condition by removingany accessibility constraint; on its own, however, the mass transit system can do little. Thus ideally thetravelway should be developed in unison with other on−going major developments within the city.

A number of mass−transit schemes have managed to capture some of these developmental benefits for theirown financial gain. This has been achieved through the commercial development of the air−space aboveterminals and interchanges; these revenues can contribute to both the capital cost of the structure and/or togeneral income.

5. Other impacts

Public transport is often used by people who do not have access to private motor vehicles and a highproportion of bus passengers tend to be children, old people and women. This means that improvements totransit services can have important social impacts. For example, suitable bus services can offer mobility towomen who may not otherwise have access to motorized transport, and can increase their access to workopportunities, and to educational and social activities.

In developing countries, the foreign−exchange requirement of a proposed investment can be an importantcriterion in the selection of a technology. Busway transit offers considerable scope for civil engineeringconstruction by local contractors and, where a local assembly or body−building industry exists, a substantialpart of bus costs can be incurred locally. As noted earlier, LRT is more dependent on imported technology,and hence a requirement for foreign exchange to pay for rolling stock and, in the case of advanced systems,signalling and power equipment. This could be off−set in some countries by its use of locally generatedelectric power rather than imported diesel fuel.

6. Economic evaluation

An economic analysis of any travelway project should try to take account of all the impacts which have beendiscussed. Many of these impacts are clearly difficult to quantify. A busway scheme is likely to improve buscommercial speeds and reliability, and therefore the potential benefits are typically: journey−time savings to

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bus passengers (including the value of increased reliability), and bus−operating−cost savings (including apossible reduction in fleet size). In general, the majority of benefits are likely to be associated with timesavings at junctions. However, the analysis should also take into account changes in journey times andoperating costs for other road users, especially if some reassignment of traffic is anticipated. Depending uponlocal geometry and traffic flows, introduction of a busway may increase or decrease the capacity available forgeneral traffic, particularly at junctions, and detailed junction analyses are required to estimate these effects.

There are no definitive studies of the economic viability of busways, but as noted earlier, bus lanes carryingmore than 60 large buses per hour per direction, are likely to yield a good economic return. Post−evaluationstudies of the economic worth of advanced LRT have been undertaken in connection with the Tunis andManila systems. In both examples the economic rate of return was estimated at just under 12 per cent.

Finally, no study has examined the crucial issue of the developmental benefit to the city centre of a travelwayscheme. It is a very complex issue since it raises questions about the city structure and its efficient growth.These are questions which go somehow beyond the bounds of transport planning, and pose major conceptualand technical problems of analysis. If the continued growth of the urban centre is an urban developmentobjective then the travelway scheme can be considered as a major positive contribution to achieving that end.

E. Planning considerations

1. Scope of planning

(a) Planning context

A primary consideration in the development of any travelway scheme is that it forms part of an overall strategytowards public−transport development within the city. The policy is likely to be one which encourages thedevelopment of public−transport facilities as a means to provide the greatest and most efficient access to thecity centre. (If the policy is one of laissez. faire, travelways are unlikely to receive any strong support andpublic transport will inevitably suffer severely from the congestion caused by other road users.) Costconstraints and demand will help determine which of the low−cost options (buses on bus lanes or buswaysand LRT) will best serve the purpose.

Given the performance figures noted earlier, busway transit and LRT are likely to be suitable in a variety oflocations, typical examples being:

− The main corridors of medium−sized cities, where public transport travel demands are up toabout 20−25,000 passengers/hour/direction;

− The secondary corridors of large cities, to complement rail mass transit;

− Outer city suburbs, to structure newly urbanizing areas.

Medium−capacity travelway systems can be viewed as a first step towards a "heavy" mass−transit system. Inthis incremental approach, a right−of−way is secured which can be used initially for a busway or LRT, andsubsequently up−graded to a metro system. The idea of such a transitway has an appeal to urban "plannerswhich dates back to the beginnings of modern urban design practice. Clearly, there would be problems ofcontinuity of service during an up−grading exercise, and there are likely to be technical problems associatedwith the change, but the basic concept of reserving land for long−term transport development hasconsiderable merit.

Planning should be concerned with both current and future travelway needs, and in the context of futureneeds the transport planner should be working very closely with his urban planning counterparts. If futuretravelways can be identified at an early stage, the opportunity arises for protecting rights−of−way before majordevelopment encroaches. In the planning and design of any new river crossing or grade−separatedinterchange, provision should also be made for the possible future installation of a travelway. For example, thenew river crossings in Istanbul all have provision for a transit lane in the median, which could accommodateeither bus or LRT. The identification of future rights−of−way should be based on sound transport analysis,rather than conceptually pleasing ideas. Travelways should only be necessary where it can be shown thattraffic demands will become high enough to warrant a protected way.

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Existing and available rights−of−way present the planner with a soft option for travelway development; again,however, there is no substitute for detailed demand analysis. Several metro systems have suffered fromunder−utilization because their alignments (along a disused rail track) do not adequately follow demandneeds. Equally, a number of suburban ring railways have been up−graded, but with no apparent success inattracting passengers; the alignments are critically at fault.

In planning either a busway or LRT system, much attention will have to be given to wider operational andorganizational arrangements as well as the design of the physical infrastructure. Both are importantcomponents for the successful implementation of the transit system; issues like integration, funding andmanagement require a realistic planning approach as to what is achievable. Too many metros have not livedup to the ambitious expectations of planners who have failed to appreciate the difficulties of organizationaland institutional change.

(b) Allocating roadspace

Where a transitway is to be inserted into an existing right−of−way, difficult issues arise over the allocation ofroadspace between the conflicting demands of different road users. In many cities, there is insufficientroadspace to meet the unconstrained demands of all road users and it is necessary to have a demandmanagement policy to guide the allocation of roadspace. In cases where existing roadspace is limited, itspartial allocation to a transit−way may be justified because:

− It can carry 20−25,000 passengers per hour and direction, whereas a lane used by carsonly is unlikely to carry more than 2−3,000 passengers per hour and direction at normaloccupancy levels;

− It may be easier to divert cars rather than buses to alternative routes;

− It may be more cost−beneficial to allocate existing roadspace to buses and to constructadditional roadspace to be used by all vehicle types, rather than to construct the infrastructurerequired for a high−capacity rail system.

The width of a busway lane should never be less than 3m (a bus being typically 2.5m in width). For mosttwo−lanes busway configurations with design speeds of 50−60km/h, the track width is likely to be 7m.Including separators, a median busway would occupy 8m of available right−of−way along running sections,and 11m at staggered bus stops. A median tram running section (two−way) can have a narrower width of only6m, but will in all likelihood have approximately similar cross−section dimensions to a busway. Evidently, eachlane of travelway will occupy more than the space formerly occupied by one vehicular road lane. A 24m wideroad might lose three or four road lanes for the provision of two travelway lanes.

A right−of−way which can accommodate a busway system can invariably accommodate a tram system. Ahigh−specification LRT would need some changes, including the provision of high−level stops and possiblegrade−separation at junctions. If such up−grading is considered to be a distinct possibility at some time in thefuture, then the right−of−way should be examined with this in mind from the outset. The land−take for LRTstations could be considerably more than that for a busway or tram system. In Manila, LRT platforms are100m in length and 3.5m wide; there is also an associated concourse area for sale of tickets and passengerdispersal. The problem of land−take in a confined space has been solved in Manila by elevating the completesystem.

2. Defining the scheme

(a) Capacity concepts

The technical literature contains many ambiguous references to the "capacity" of alternative transit systems(metro, light rail, bus etc.). Such statistics usually refer explicitly or implicitly to "line−haul capacity". However,it is also important to consider "passenger−transfer capacity", i.e., the maximum number of passengers whocan board and/or alight at a stop/station during a given time period since bus−stop/station capacity is usuallythe limiting factor in a transit system. For busway transit in particular maximum line−haul throughputdecreases as passenger−transfer demands increase. Line−haul capacity is a variable and it is not possible toquote a single "capacity" figure for a transit system without reference to the de

Documents

Provision of Travelway Space for Urban Public Transport in ... · Provision of Travelway Space for Urban Public Transport in Developing Countries United Nations Centre for Human Settlements