Patrick Hasson Federal Highway Administration Midwestern Resource Center Engineering Safer Intersections

Crash Cause by Factor Vehicle 12% Roadway34% Driver 93% 93% 3 % 57 % 2 % 27% 6 % 1 % 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.

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

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 Page Various Articles

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

Theoretical analysis Intersection entry categories legalsafeintentionaltypical time after red Ayesyesyesgreen/yellow Bnoyesyes0 to ~1 Cnonoyes~1 to 3+ Dnonono3- 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

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.

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

Related Information Ongoing/Completed Research Projects – North Carolina (NC State) – 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

Engineering Solutions Can Make a Difference 1. Signal timing, type, lens size, and placement i. Clearance intervals (all red phase) ii. Length of yellow phase 2. Sight distance 3. Unwarranted or non-standard signal removal 4. Geometrics -vertical curvature and mainline road width 5. Speed and volume/capacity 6. Intersection Advance Warning Flashers 7. Pavement Treatments (skid resistance and markings) 8. Left turn lanes and phases 9. Pedestrian Signals

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 0 P( rlr ) 0 1 Volume 0 P(rlr) 0 1 Cycle Length 0 P(rlr) 0 1 P(max-out) 0 P(rlr) 0 1 Yellow Int. Courtesy TTI

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

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

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/sec 2 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 DILEMMA ZONE AND YELLOW TIME Courtesy NC State

for speed limit 40 MPH (NCDOT standard Y = 4.0 sec) reactiondecel dilemma dilemma time, (t)rate, (a)distancetime secft/sec 2 ftsec DILEMMA ZONE AND YELLOW TIME Courtesy NC State

for speed limit 55 MPH (NCDOT standard Y = 5.1 sec) reactiondecel dilemma dilemma time, (t)rate, (a)distancetime secft/sec 2 ftsec DILEMMA ZONE AND YELLOW TIME Courtesy NC State

ENGINEERING COUNTERMEASURES Increase yellow duration Courtesy TTI

VERTICAL CURVATURE AND MAINLINE WIDTH

All Red Clearance Interval Michigan Study

Left turn Lanes and Phases

ENGINEERING COUNTERMEASURES Provide advance warning of yellow interval Courtesy TTI

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

Alternative intersection designs can reduce major conflict points

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

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

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)

THANK YOU Patrick Hasson