Patrick Hasson Federal Highway Administration Midwestern Resource Center

1. Engineering Safer Intersections Patrick HassonFederal Highway Administration Midwestern Resource Center

2. Crash Cause by Factor Roadway 34% Driver 93% 3 % 27% 57 % 3 % 1 % 6 % 2 % Vehicle 12%

3. Program History • Created by FHWA in 1995 as community based safety program – 31 communities. • Expanded in 1998 with DaimlerChrysler and American Trauma Society. MISSION To continually reduce the incidence of red light running in order to prevent related crashes, trauma center admissions and fatalities.

4. 1100 1000 900 Background – The Numbers • Fatality rate dropped 12% from 1992 to 1998. • 10% decrease in fatality numbers from 1996 to 1999 – our most aggressive years. crashes injuries 91,000 Crashes 90,000 Injuries 956 Fatalities Estimated $7 Billion a year in costs

5. Background - Products • Step by Step Guide • Synthesis and Evaluation of RLR Automated Enforcement Programs • Association of Selected Intersection Factors with Red Light Running Crashes • Web Pagewww.fhwa.dot.gov • Various Articles

6. Unintentional 1 Intentional P(stop) 0 0 Travel Time, s 4 8 Dichotomized Driver Population Courtesy TTI

7. Theoretical analysis Intersection entry categories legal safe intentional typical time after red A yes yes yes green/yellow B no yes yes 0 to ~1 C no no yes ~1 to 3+ D no no no 3- to green • entry types B and C most amenable to cameras • entry types C and D can cause RLR crashes … focus on type C intersection entries Courtesy NC State

8. Engineering Solutions? • Insufficient information on full range of possible improvements. • Evidence that engineering can be effective –UK, Michigan, HSIS, Others. Challenge: Criteria to guide jurisdictions in reviewing the safety of their intersections could aid better decision making.

9. FHWA/ITE Project • “Practitioners Guide” • Stand-alone to make an intersection safer. • Describes engineering features that should be examined prior to applying automated enforcement. Spring 2002

10. Related Information • Ongoing/Completed Research Projects • North Carolina (NC State) • www.itre.ncsu.edu/rlr • Texas(Texas Transportation Institute) • Identify factors affecting RLR frequency • Develop model of the RLR process • Identify candidate countermeasures • Municipalities using cameras do engineering review prior to camera installation. • Reviews are inconsistent in coverage/approach

11. Engineering SolutionsCan Make a Difference • Signal timing, type, lens size, and placement • Clearance intervals (all red phase) • Length of yellow phase • Sight distance • Unwarranted or non-standard signal removal • Geometrics -vertical curvature and mainline road width • Speed and volume/capacity • Intersection Advance Warning Flashers • Pavement Treatments (skid resistance and markings) • Left turn lanes and phases • Pedestrian Signals

12. P(rlr) 1 0 0 Volume P(rlr) P(rlr) P(rlr) 1 1 1 0 0 0 0 Cycle Length 0 0 Yellow Int. Theory:RLR Exposure Events 1. Flow rate on the subject approach 2. Number of signal cycles 3. Probability of max-out 4. Yellow interval duration P(max-out) Courtesy TTI

13. Theory:Driver Behavior Factors 1. Travel time 2. Speed 3. Actuated control 4. Coordination 5. Headway 6. Approach grade 7. Yellow interval 8. Expected delay 9. Signal visibility Courtesy TTI

14. Measures of Effectiveness? 1. Number of vehicles running red 2. Number of vehicles in or entering intersection when conflicting phase is green 3. Number of vehicle-vehicle conflicts

15. DILEMMA ZONE AND YELLOW TIME • Intent of yellow interval: provide time to reach the stop/go bar if no room to stop • one safe move (stop or go) usually provided • assumptions: 1.0 sec reaction, 10 ft/sec2 decel. rate • “standard” driver still must choose correctly • not all drivers can meet standard assumptions • older drivers: 1.5 sec reaction time • distracted time: 1.25 sec is typical Courtesy NC State

16. DILEMMA ZONE AND YELLOW TIME for speed limit 40 MPH (NCDOT standard Y = 4.0 sec) reaction decel dilemma dilemma time, (t) rate, (a) distance time sec ft/sec2 ft sec 1.0 10 -4 -0.1 1.0 9 15 0.3 1.5 10 25 0.4 1.5 11 10 0.2 Courtesy NC State

17. DILEMMA ZONE AND YELLOW TIME for speed limit 55 MPH (NCDOT standard Y = 5.1 sec) reaction decel dilemma dilemma time, (t) rate, (a) distance time sec ft/sec2 ft sec 1.0 10 -6 -0.1 1.0 9 31 0.4 1.5 10 35 0.4 Courtesy NC State

18. ENGINEERING COUNTERMEASURES Increase yellow duration Courtesy TTI

19. VERTICAL CURVATUREAND MAINLINE WIDTH

20. All Red Clearance Interval Michigan Study

21. Left turn Lanes and Phases

22. ENGINEERING COUNTERMEASURES Provide advance warning of yellow interval Courtesy TTI

23. ENGINEERING COUNTERMEASURES Sometimes alternatives such as roundabouts can provide significant safety and operational benefits.

24. ENGINEERING COUNTERMEASURES Alternative intersection designs can reduce major conflict points. 52 44

25. Concepts for Intersection Collision Avoidance • Infrastructure-based systems can: • Warn “violating” driver to obey traffic signal, stop sign, or railroad crossing signal • Warn other drivers of potential conflict with violating driver • Advise drivers when safe to turn at traffic signal or to move away from stop sign • Warn drivers of potential conflict with pedestrian or pedalcyclist

26. Traffic Signal Violation Warning Intelligent Rumble Strips Prototype Strobe Roadside Flashing Warning Sign Warning Sign for Other Drivers

27. Keys to Successful Red Light Camera Programs • Traffic safety focus • Public acceptance • Education • Explain where the money goes; • Fairness: Infrastructure or behavior? • Legislative, Judicial and Enforcement support • Learn from the experience of others • High level of “customer service” (answer violator calls)

28. THANK YOU www.fhwa.dot.gov www.ite.org Patrick Hassonpatrick.hasson@fhwa.dot.gov708-283-3595