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IE 486 Work Analysis & Design IIIE 486 Work Analysis & Design II

Lecture 16 – Transportation Human Lecture 16 – Transportation Human FactorsFactors

Dr. Vincent G. DuffyDr. Vincent G. DuffyThursday March 23, 2007Thursday March 23, 2007

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Lab 3, Lab 4 & Review for exam 2Lab 3, Lab 4 & Review for exam 2

Lab 3 can be turned in today or tomorrow Lab 3 can be turned in today or tomorrow for full credit. for full credit.

Lab 4 will be introduced tomorrow.Lab 4 will be introduced tomorrow.

Review for exam 2 will also begin Review for exam 2 will also begin tomorrow. Lab 3 will be included in the tomorrow. Lab 3 will be included in the review discussion and on exam 2.review discussion and on exam 2.

Exam 2 will be held in class next Tuesday, Exam 2 will be held in class next Tuesday, March 27.March 27.

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Transportation Human FactorsTransportation Human Factors

Today: primarily Automotive & PublicToday: primarily Automotive & Public

there are certain features of vehicles that make them stand there are certain features of vehicles that make them stand apart from other systems apart from other systems

– yet solutions incorporate ideas from other chaptersyet solutions incorporate ideas from other chapters

Some statistics for considerationSome statistics for consideration

– every year 500,000 people die (worldwide) in autosevery year 500,000 people die (worldwide) in autos

– 40,000 in the U.S. with a cost of $100 Billion/yr.40,000 in the U.S. with a cost of $100 Billion/yr.

– As high as 90% of accidents are human errorAs high as 90% of accidents are human error

issues include: visibility, hazards and collisions, impaired issues include: visibility, hazards and collisions, impaired drivers, training & automationdrivers, training & automation

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Resource competitionResource competition

Predicting # of fatalities (FA) based on Predicting # of fatalities (FA) based on market penetration (MP)market penetration (MP)– Glance duration (GT), # of glances (G), Glance duration (GT), # of glances (G),

frequency of use (FU)frequency of use (FU)– And shows that we should balance benefits of And shows that we should balance benefits of

any in-vehicle device with the potential fatalities any in-vehicle device with the potential fatalities that it may cause.that it may cause.

FA = FA = (1.019 )(1.019 )(currentyear-1989)(currentyear-1989) (MP)[-0.33+0.0477(GT)(MP)[-0.33+0.0477(GT)1.51.5 (G)(FU)] (G)(FU)]

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Further information on glance timesFurther information on glance times

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Automotive human factorsAutomotive human factors

Competing goals: Competing goals: – productivity - timely trip and safetyproductivity - timely trip and safety

deaths per year are relatively constant, but decreasing per deaths per year are relatively constant, but decreasing per passenger milepassenger mile– and statistics of the whole population are quite different from those of young, and statistics of the whole population are quite different from those of young,

old and males.old and males.

The task includesThe task includes– maintaining lane position - 2nd order control taskmaintaining lane position - 2nd order control task– speed keeping - ‘longitudinal task’ (over time)speed keeping - ‘longitudinal task’ (over time)

a good measure of performance - estimated time to lane a good measure of performance - estimated time to lane crossingcrossing

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Tracking & control of a vehicle is related to performance capabilities Tracking & control of a vehicle is related to performance capabilities and limitations. Performance can be considered through intermediate and limitations. Performance can be considered through intermediate performance measures such as lane keeping, or others (hit/miss) such performance measures such as lane keeping, or others (hit/miss) such

as hazard avoidance.as hazard avoidance.

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Driver’s information processing tasksDriver’s information processing tasks

Centered around the model presented in Centered around the model presented in figure 17.1 figure 17.1

In cab Road SideViewing Scanning Non-visual Tasks Auditory Motor

Cognitive

Exit2 Miles

First order Tracking 2nd Order

Tracking

TLC – time to lane crossingSecondary Tasks

Primary task:Road Hazard MonitoringForward Vision

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Visual secondary tasksVisual secondary tasks

Electronic devices can act as sources of distractionElectronic devices can act as sources of distraction– most common denominator of allmost common denominator of all

visual attention - amount of time that visual visual attention - amount of time that visual resources are diverted away from primary visual resources are diverted away from primary visual attentionattention

Danger when time is larger than some minimum valueDanger when time is larger than some minimum value

amount of danger is proportional to vehicle speedamount of danger is proportional to vehicle speed

suggestions for controls and ‘cabin’ environment are suggestions for controls and ‘cabin’ environment are related to materials from chapters 4, 8 & 9 on visual related to materials from chapters 4, 8 & 9 on visual systems, controls and displayssystems, controls and displays

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Speed and hazardSpeed and hazard

Hazard responseHazard response– estimated time to react to unexpected objects is importantestimated time to react to unexpected objects is important

typical reaction time 2.5 seconds is significantly more than typical reaction time 2.5 seconds is significantly more than that found in traditional psychology experiments (in the that found in traditional psychology experiments (in the laboratory)laboratory)

speed provides a quadruple threatspeed provides a quadruple threat

increased likelihood of loss of controlincreased likelihood of loss of control

decreased probability of timely detection of hazarddecreased probability of timely detection of hazard

increased travel distance (in same time)increased travel distance (in same time)

increased damage at impactincreased damage at impact

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Speed and hazardSpeed and hazard

Small cars were more likely to be ‘rear-ended’ because Small cars were more likely to be ‘rear-ended’ because they were perceived to be farther awaythey were perceived to be farther away

p.445 Wickens; re: Evans study & previous notes; p.445 Wickens; re: Evans study & previous notes; Eberts studyEberts study

average separation distance is 1.3 sec. While average average separation distance is 1.3 sec. While average minimum safe stopping is 2 sec.minimum safe stopping is 2 sec.

Drivers tend to believe they are less likely to be in an Drivers tend to believe they are less likely to be in an accident than the average driver accident than the average driver

related to bias & decision making from previous discussion related to bias & decision making from previous discussion – eg overconfidence – eg overconfidence (see p.446-447 re: risky behavior)(see p.446-447 re: risky behavior)

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Novel design solutionsNovel design solutionsAffecting behavioral changeAffecting behavioral change - Carrot or the stick - which is - Carrot or the stick - which is more effective?more effective?– drivers were more likely to wear seatbelts if police officers randomly rewarded drivers were more likely to wear seatbelts if police officers randomly rewarded

drivers for wearing seatbelts drivers for wearing seatbelts Mortimer, Goldsteen, Armstrong, Macrina, 1990, Effects of incentives and enforcement on the use of Mortimer, Goldsteen, Armstrong, Macrina, 1990, Effects of incentives and enforcement on the use of seatbelts by drivers, Journal of Safety Research, 21, 25-37.seatbelts by drivers, Journal of Safety Research, 21, 25-37.

System re-designSystem re-design – visual cues – visual cues– Tri-light systemTri-light system - amber light turned on if ‘accelerator’ pedal - amber light turned on if ‘accelerator’ pedal

is released is released

rather than two light - off/brake light systemrather than two light - off/brake light system– Shinar, 1995, Field evaluation of an advance brake warning system, Human Factors, 37 (4) 746-Shinar, 1995, Field evaluation of an advance brake warning system, Human Factors, 37 (4) 746-

751.751.

Design should capitalize on Design should capitalize on expectancyexpectancy– Eg. Traffic lights should be standardized according to speed of typical driver Eg. Traffic lights should be standardized according to speed of typical driver

approachapproach

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Arguments about ‘adaptive’ driversArguments about ‘adaptive’ drivers

Consider risk Consider risk homeostasishomeostasis idea idea– hypothesis: antilock brakes enable people to driver faster hypothesis: antilock brakes enable people to driver faster

or more recklesslyor more recklessly

thereby negating the safety advantagethereby negating the safety advantage– automation could make drivers more complacentautomation could make drivers more complacent

However, making wider lanes made significant However, making wider lanes made significant improvements on safetyimprovements on safety

Impairment can be from fatigue, alcohol & ageImpairment can be from fatigue, alcohol & age– older drivers may drive more cautiously, slowly to avoid riskolder drivers may drive more cautiously, slowly to avoid risk

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Training…Training…

The ability of instructor to create emergency conditions is low in real environment hence, some benefits can be gained from simulators

It is noted that there is little evidence to support the idea that mandatory drivers training programs improve safety

And visual acuity tests don’t test critical skills such as vision of dynamic events night vision or visual attention skills

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Public transportation – other cost Public transportation – other cost considerationsconsiderations

Generally 30times more safe to take the bus, 7times more safe to take the subway

efforts needed to gain ‘behavioral changes’ include making travelers aware of lower risks, lower

costs and greater efficiency of public transportationRelation between research and fatalities

$ Research years of lost life

traffic injuries 112M4.1M

cancer, heart disease & stroke 1.5B 3.8M greater than 10x money spent for medical research

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We sometimes will We sometimes will consider aspects of human consider aspects of human

factors and engineering factors and engineering such as controls, displays such as controls, displays or safety, independent of or safety, independent of the application domain. the application domain. Here we will introduce Here we will introduce safety in relation to the safety in relation to the

transportation application transportation application domain. Later we will domain. Later we will

revisit safety. revisit safety. For this Transportation For this Transportation

Safety discussion, consider Safety discussion, consider this supplementary 1 page this supplementary 1 page of notes/ handout/book by of notes/ handout/book by Henderson,“100 Ways to Henderson,“100 Ways to live to be 100”. Section on live to be 100”. Section on

Safety.Safety.