From IDS to CICAS: Rural Intersection Crash Avoidance

1. From IDS to CICAS: Rural Intersection Crash Avoidance “Towards a Multi-state Consensus on Rural Intersection Decision Support”Pooled Fund MeetingMinong, WisconsinJune 12, 2006

2. National Motivation • 2.6 million intersection related crashes annually • Represents 41% of all 6.33 million police reported crashes • In Minnesota, 129 out of 583 (22.1%) fatal crashes are at intersections • In the US, 8,659 of 38,252 (22.6%) of fatal crashes were intersection related • 31.7% occurred at signalized intersections • 68.3% occurred at unsignalized intersections (stop sign, no controls, other sign). NHTSA, Traffic Safety Facts 2003, January 2005Minnesota Office of Traffic Safety, Minnesota Motor Vehicle Crash Facts, 2003

3. Intersection Decision Support (IDS) • Focus on driver error causal factors • Fatal and life changing intersection crashes • Provide the driver with information that will improve judgment of gap clearance and timing • Keep major corridors flowing • Deploy where the fatalities/crashes warrant deployment • New tool for the traffic engineer

4. Focused on Recognized National Problem Guidelines for Implementation ofAASHTO Strategic Highway Safety Plan • NCHRP Report 500: Vol. 5 Unsignalized Intersections • Identifies objectives and strategies for dealing with unsignalized intersections • Objective 17.1.4 Assist drivers in judging gap sizes at Unsignalized Intersections • High speed at grade intersections

5. Approach • Measure gaps that drivers take under actual road conditions. Collect data regarding intersection entry behavior. • Evaluate suite of sensors to ensure that they are able to measure those gaps accurately and able to distinguish between unsafe and safe gaps at the level that the existing literature specifies. • Develop set of interface concepts with which to communicate the existence of an unsafe vs safe gap in the intersection to the driver. • Evaluate selected set of interface concepts.

6. Unsafe gap is main risk factor Percentage of all crossing path crashes based on Najm W G, Koopmann J A, and Smith D L (2001) Analysis of Crossing Path Crash Countermeasure Systems. Proc. 17th Intl Conference on Enhanced Safety of Vehicles

7. Goal • Design and evaluate information “concepts” for sign elements to support detection and acceptance of safe gaps in mainline traffic. • Explore out of the “toolbox” concepts. • Prohibitive frame: Provide information regarding unsafe gaps. • Final judgment of safety and responsibility for action must remain with driver.

8. Concepts Detect Inform

9. Safe Gap Definition 2-stage crossing strategy - Driver stops in median 1-stage crossing strategy - Driver does not stop in median 12.5 s 8.0 s 7.5 s 7.5 s System accounts for worst-case scenario of an older driver making a left turn (in 1-stage). AASHTO Green Book, 2001; FHWA Older Driver Handbook, 2001

10. Assumptions • Many factors determine gap safety. • As a non-cooperative system, these sign concepts do not have “preview” of all these factors. • Therefore, system is “blind” and must make assumptions about condition. • With vehicle classification, will be able to adjust gap for vehicle. • For liability reasons, sign concepts must assume worst-case condition. • Left turns + older drivers + 1-stage • This may be perceived as non-credible to drivers in all other conditions.

11. Virtual Environment for Surface Transportation Research • Ability to model precise reproductions of geo-specific locations • Resolution = 2.5 arc-minutes per pixel • 8 channels • 3D surround sound • Car body vibration • Force feedback steering • Power-assist feel on the brakes • 3-axis electric motion system

12. Methods • 5 sign conditions • Within-subjects • 2 age groups • 24 young; 24 old • Gender balanced • 2 light conditions • Day vs. night • 12 participants per group/condition

13. Main Lessons • Additional information can be used. • All sign concepts resulted in shifts towards the safe gap threshold • However, threshold was perceived as too conservative (not personalized) • Compliance increases when visibility of traffic condition is reduced. • Old drivers, night condition • Dynamic aspects of (Icon and Split-hybrid) signs facilitate comprehension. • Map sign changes to changes in environment • Young drivers may “calibrate” system.

14. Next Steps • “Personalized” gap thresholds • Cooperative systems • MUTCD compliant formats • Close interaction with MnDOT engineers • Test compliant formats in simulator • Validate with test site experiment • Field operational testing • Consider role of signs in larger safety programs (Training & Education). • Older drivers must perceive own limitations to appreciate need for decision support • Drivers need understanding of functions (include in licensing tests)

15. Pooled Fund Study(CA, GA, IA, MI, MN, NC, NH, NV, WI) • Goals: • Characterize rural intersection crashes throughout USA • Identify regional differences in driver behavior • Use information to design ubiquitous system deployable throughout US • Setup a broad base for a field operational test • Key Tasks: • Crash analysis in each partner state • Driver behavior data collection in each partner state • Analyze and archive driver behavior data

16. Cooperative Intersection Collision Avoidance System (CICAS):Stop Sign Assist CICAS

17. Years One thru Three Years Four and Five CAMP DVI CICAS Work Plan (5 Years) IDS CICAS Situation Analysis Protocol Standardization Protocol Evaluation Functional Scope Concept Study Translation Study Validation Study Pre-FOT Sign Concepts Deployable Signs Compliant Signs Parameters Gap Model Alert / Timing Algorithms FOT

18. Situation Analysis • Macroscopic • Common scenarios • Outliers • Onsite observation • Context • Atypical cases • Crash reports • Common risk factors

19. Gap Model / Algorithms • Macroscopic • License plate reader • Demographics • Microscopic • Instrumented vehicle • Process stages • Predictive models • Sensitivity analysis • Practical analysis • Algorithms • Gap threshold, timing • Complete logic • Platoons, non-cooperative cases, etc.

20. Translation Study • Integrate algorithm • Convert “concepts” to compliant signs • Inform, warn, and advise • Test legibility and comprehension. • Replicate sim evaluation • Do compliant signs retain concept benefits? • Interaction with DVI?

21. Technical Steps to FOT/Deployment • Minimal Sensor Sets • Mainline: Function of variation in mainline traffic speed and sensitivity of driver to timing (HF phase) • Have data showing speed variation and comparison to point sensors. • Minor road: Function of sensitivity of vehicle type to gap alert/warning timing • Definition of gap previously used shows little sensitivity to vehicle type. • Microscopic study of driver behavior needed to resolve this issue.

22. Technical Steps to FOT/Deployment • Driver behavior data • Macroscopic data • Pooled fund: data collection in eight states with portable intersection surveillance system • Validation Study: Microscopic Data • Fully instrumented passenger car • Fully instrumented heavy truck • Fully instrumented intersections • Testing in Minnesota

23. Technical Steps to FOT/Deployment • Driver-Infrastructure Interface • Mechanical & electrical design • Placement • Cost • Reliability • Communication Mechanism • Dedicated short range Communications (DSRC) • Wireless Access for Vehicular Environments (WAVE; 802.11p) • FCC allocated Oct. 21, 1999 • 75 MHz of spectrum at 5.9 GHz • 7 licensed channels • Hardware and protocols under development

24. Technical Steps to FOT/Deployment • Definition/Implementation of ‘Cooperation’ • Driver-Infrastructure Cooperative: demographic, personal preference data • Storage (on person, in-vehicle?) • Broadcast (from person, through the vehicle?) • Auto manufacturers seem opposed to personal data broadcast and used by infrastructure system • Vehicle-Infrastructure Cooperative: vehicle performance, weight, size, etc. • Driver intent (turn signal, steering wheel position, foot on clutch, brake, throttle, gear selection, etc.)

25. Validation Study:Support of On-site Human Factors Testing • Build Instrumented Vehicle • Wave-DSRC radios • Integrated eye tracker • Steering, brake, throttle measurements • Full traffic data • Day, night testing • Support analysis • Location, speed, etc. of all other vehicles in vicinity of intersection

26. Validation Study:On-site Human Factors Testing

27. Pre-FOT Years One thru Three FOT Years Four and Five FOT IDS CICAS Situation Analysis Protocol Standardization Protocol Evaluation Functional Scope Concept Study Translation Study Validation Study Pre-FOT Sign Concepts Deployable Signs Compliant Signs Parameters Gap Model Alert / Timing Algorithms FOT

28. Goal • Provide real world data of system effect on gap acceptance and driver perceptions to support policy decisions for deployment trials.

29. Method • Recruit local residents using own vehicles • N = 30 • Male and female • Young and old • Compare behavior before and after installation of system.

30. Plan • Methodology • Data • Harmonization • Pilot FOT • Evaluate methodology • Final design iteration • Full FOT • Naturalistic scenario • Macroscopic • Microscopic? • Deployment verdict

31. FOT Instrumentation:Vehicle Cooperative System