Transportation Human Factors

1. Transportation Human Factors Chapter 17

2. Automotive Human Factors • Importance – over 40,000 fatalities per year in the US with 90% attributable to human error. • Overview: • Task analysis of the of the roadway system • Critical issues – visibility, hazards & collisions, impaired drivers, training & selection, and automation

3. Task Analysis of the Vehicle Roadway System • Tracking task – driving is a second order control with preview • The multitasking environment – primary task is lane keeping and road hazard monitoring (primary visual attention lobe (PVAL). Secondary tasks are signs, radio, maps, etc. • The cabin environment – simple user-friendly & displays should be of high contrast , interpretable, & easy to read

4. Task Analysis of the Vehicle Roadway System

5. Visibility • Anthropometry – seating adjustments and ability to reach adjustment controls • Illumination – night time risk of fatality is 10 times greater • Signage • Minimize visual clutter • Place consistently • ID signs clearly – shape, color, etc. • Efficient verbal signs • Resource Competition

6. Resource Competition

7. Hazards and Collisions • Control loss – icy roads, lane width, lapse of attention, etc. All directly related to bandwidth of correction which is related to speed (most critical factor) • Hazard response – poor visibility or inattention. Key parameter is time to react (2-4 sec). Again speed is most critical factor • Speeding – in addition to the above two, increases distance before successful avoidance maneuver and increases damage impact

8. Relationships of Hazard Response Components

9. Accident Solutions • Slightly over 40,000 fatalities per year since 1993 with 20% increase in miles driven. Peak years 69, 70, & 72 had 55,500 per year. • Compliance – strict law enforcement (speeding & seat belt use) • Protective Devices – seat belts & air bags • Sensing – 25% of accidents result from rear end collisions. Tailgating is primary cause. Devices are brake lights and their placement (possible amber on deceleration)

10. North Carolina Seatbelt Law Enacted Sept 1985

11. Cognitive Factors in Driving • Expectancy – People respond much slower to the unexpected • Prediction – Highway design & traffic control devices should help the driver forecast what is coming up (positive guidance). • Risk – Driver training & experience can help the driver in ascertaining the risk factor

12. The Impaired Driver • Fatigue – Problem is vigilance with low frequency events (surprises) • Alcohol (50% of fatalities) As low as .05% will impair. Interlocking devices? • Age – Young & older drivers have more accidents. Youth (inexperience & risk taking) and Older (cognitive processing slows)

13. Fatality Rates – Age & Gender

14. Training and selection programs have only limited success

15. Automobile Automation • Collision monitors • Automated navigation systems • Global positioning systems • Driver monitors • Intelligent Vehicle Highway System (IVHS)

16. Public Ground Transportation • Statistically it is: • 30 times safer to take the bus • 7 times safer to take a train or subway • Important human factors issues is to induce behavioral change toward mass transit • Trains & subways have rigid infrastructures while buses use the same roadway systems as cars

17. Aviation Human Factors • The Tasks – Multitask & higher order tasks like an auto driver’s tasks but more complex • Tracking & flight control – Aircraft has 6 degrees of freedom while auto has 2 • The displays – many more • Flight Control Dynamics – Sluggish to overcome inertia in larger aircraft & some third order tasks • Axis Interactions • Aircraft pilots must follow strict procedures

18. Complexity of Tracking, Flight Control Dynamics, & Displays

19. Situation Awareness Pilot must have an understanding & awareness of location & implications of future hazards – display design is of utmost importance

20. Situation Awareness

22. Social Context • On commercial jetliners a pilot is a member of a 2 or 3 man team • Must interact with other teams – air traffic controllers, ground crews, cabin crew, etc. • Good communication is paramount • eg., it is better to say “your altitude is too low” rather than “have you checked your altitude lately” • Aeronautical Decision Making (ADM) and Crew Resource Management (CRM) training is effective

23. ADM & CRM Training Results

24. Stress & Impairments • Training & licensing qualifications are much more stringent • High stress in student pilots • Motion sickness in light aircraft • Emergency situations can be very stressful • Military pilots must carry out mission in hostile environment

25. Aircraft Automation • Auto pilot • Head up displays • Highway in the sky • Lock on target assist • Collision alerts • Flight management systems to optimize routes

26. Air Traffic Control Tasks Are Highly Stressful • Controller is assigned an aircraft as it enters the controlled space • Insures safe and expeditious flow of aircraft in controlled space • Interacts continuously with other controllers in the tower • Communicates instructions to pilot while monitoring displays that ID locations of all aircraft in the controlled space

27. Typical Air Traffic Control Display