Human Factors in Transportation

Dr. Wen Cheng, P.E., T.E., PTOE

July 6th,2010

Cal Poly Pomona

Learning Objectives• Understand human variation and related

design principles• Understand the human factor impact in the

mode of pedestrian, bicyclist, highway, rail transport and air transport

• Describe how to conduct LOS analysis for walkways

• Describe the application of PRT in engineering design

Integrated System

Transportation Users

MachineEnvironment

Human Variation

Personal difference• Gender

– Male– Female

• Age (driver example)– 5.1% 19 years of age and under– 9.9% 70 years of age and above– 85% in between

• Many other factors– ……

Human requirements of transportation system

• Primary– Increase of speed– Increase of range– Increase of carrying capacity

• Secondary– Safety– Comfort and convenience

Design Principle

Pedestrian

Pedestrian Characteristics• Space needs (required for sidewalk,

elevator capacity analysis)– Body ellipse

• Walking speeds– Range from 2.5 to 6.0 sec/ft– Avg. 4.0 ft/sec – If >20% is elderly users, then design speed

=_______ ft/sec

Some ped. accident facts• Most prevalent during morning and afternoon

peak hours• Friday and Saturday accidents are over-

represented and Sunday are under-represented• Adult ped. aged 45-65 are equally likely to

occur at intersections or mid-block• Children ped. accidents mostly occur at mid-

block or intersection? • Elderly ped accidents are more prevalent at

mid-block or intersection?

Ped. facilities

3 types of design strategies for ped. • Segregation, via spatial separation of ped.

and vehicular networks

• Separation, via the allocation of either time (e.g. ?) or space (e.g. ?)within a shared ped.-vehicle facility

• Integration, via shared use of facility

Sidewalks: except ped. or vehicular flows are very light, it is considered to be desirable

Refuge islands

• Allow the ped. to cross street in two stages• Types:

– Formal ped. refuges– Splitter islands at intersection approaches– Medians, etc.

• Appropriate where:– Ped. crossing movements are concentrated,

but overall # don’t warrant a ped. crossing

Ped. Refuge island

Curb Extension (i.e., choker)• Consist of local widening of sidewalk into the

roadway• Typically at the expense of parking spaces• Reduce walking distance and ped. exposure

Ped. Barrier: in locations of high ped. activity, used to control ped. movement

Traffic signals• 3 types:

– no explicit recognition: peds. have to observe vehicular signals

– Concurrent phasing: “walk” / “do not walk” displace at the same time with green circle for vehicular traffic

– Exclusive ped. phasing: no potential conflicts with any vehicular movements

Ped. Signal

Ped. crossings• Three types:

– Zebra crossings=striped crossing + flashing signals (usu. yellow)

– Pelican crossings=striped crossing + ped. operated signals– Marked crosswalk: indicate a place where ped. can cross,

but w/o any provision for active control of motorists

Grade separated facilities

• 2 types:– Underpass– Overpass

Which one you prefer?

• Appropriate:– When high speed/traffic

flow– Where high ped.

cccident problem

Ped. malls• The ultimate in segregation of ped. Provision is

to have a ped.-only facility, like shopping malls.

Integrated facility• Woonerf, Dutch word for “living street”• Typically used only on residential streets. • Is a space shared by pedestrians, bicyclists,

and low-speed (<10mph) motor vehicles.

Facility for the disabled

• Tactile surface at ped. crossing

• Audible ped. signals• Curb ramps• Raised guide strips• ADA design guidelines:

– max. grade on ped. overpass ramp

– location of signal post, etc.

Walkway LOS factors

Effective walkway width (WE)

Walkway LOS criteria

Bicyclist

Bicyclists at risk

• Bicycling represents 5~15% of all urban trips

• Bicyclists are over-represented in casualty accidents.

• Bicyclists most at risk are the young• There is a significant over-representation

of bicycle accidents at night time and in low-light conditions

Truck under-run barrier

Safety strategies for bicyclists

• Protection (e.g., wearing helmets, use of brightly colored clothing, use of under-run barriers on trucks, etc.)

• Legislation (e.g., sanctions on speeding, alcohol use, bicyclist conspicuity, etc.)

• Road and traffic environment (e.g., traffic calming, the provision of bicyclist facilities, etc.)

Bicycle facilities

• Shared roadway (no bikeway designation)• Signed shared roadway : with a

designated bike route sign• Bike lane or bicycle lane: a portion of the

roadway designated by striping or pavement markings

• Separate bike path: exclusively used for bicyclist and separated from roadway

Bikeway Types

Bicycle users

• Advanced bicyclists: experienced riders who can operate under most traffic conditions

• Basic bicyclists: casual adult and teenage riders, they are less confident of their ability in traffic without special provisions for bicycles.

• Children: preteen drivers whose roadway use is initially monitored by parents

Bicyclists

Automobile Drivers

Driver Information Need

•Control level (info from basic senses)

•Guidance level (info of constantly changing environmental)

•Navigation Level (maps, directional signs, landmarks, etc.)

Info Decision Making Action

•Physical operation of vehicle (steering, acceleration/deceleration)

•Selecting speed and path

•Trip planning, direction finding

Driver Perception & Reaction• Perception-reaction time (PRT)

– Also called PIEV time (perception, intellection, emotion and volition)

• Perception: Continuous collection of information through the senses

• Identification: Interpretation of this information in the brain

• Emotion: Reasoning, problem solving, and decision-making in response to the information

• Volition: The resulting dynamics of both the driver (body movements to affect a response) and the vehicle

Effects of PRT– Car following– Yellow times at traffic signal (usu. add 1 sec to the

yellow time for PRT)– Stopping sight distance (usu. 2.5 secs for PRT)– Decision sight distance

• A stop on a rural road: PRT = 3.0 seconds • A stop on an urban road: PRT = 9.1 seconds • A speed, path, or direction change on a rural road: PRT = 10.2

to 11.2 seconds • A speed, path, or direction change on a suburban road: PRT =

12.1 to 12.9 seconds • A speed, path, or direction change on an urban road: PRT =

14.0 to 14.5 seconds

Human Sensor Process

• Visual (Sight)– Legibility distance– Cone of Vision– Eye shifting and fixating

• Movement• Equilibrium• Hearing• Others (smell, hunger, thirst……)

5 Principles to present info• Primacy: control level > guidance level > navigation

level

• Do not overload: Processing channel limitation

• Do it before you get on the road: A priori knowledge

• Spread Info• Do not surprise: avoid left exit, hidden dip,

etc.

Design Examples Considering PRT

Example#1: a 2-lane road

Example#2: An urban intersection

Example#3: A freeway off ramp

Example#4: A work zone

Transit and Rail Passenger

Terminal design #1: space needed

Terminal design #2: Info. neededInternational railroad pictographs

Terminal design #2: Info. neededInternational signs at airports

Public transport vehicle design factors• Social factors: (level of crowding,

presence of traveling companions, etc.)

• Passenger characteristics: (proneness to sickness, physical and mental health, etc.)

• Spatial factors: (seat width, leg room, standing space, etc.)

Air Transport Passenger

Terminal design #1: activity times

Terminal design #2: space needed

Air transport passenger cabin design

• Spatial (cabin size, seating layout, etc.)• Physiological (temperatures, odors,

lighting, noise, etc.)• Psychological (vista, space, safety,

expectations, etc.)• Activity provision (providing eating,

drinking, reading, watching films, etc.)

THANK YOU!!!