Evaluation of the Safety Effects of Red-Light Cameras Sponsored by FHWA’s ITS Joint Programs Office Conducted by BMI and Battelle

What Is Known A number of different US and foreign research studies Appear to indicated that RLCs decrease angle collisions and increase rear-end collisions But major methods problems with most studies

Issues That Cause Problems Regression-to-the-mean due to treatment of high-accident locations “Spillover effects” to other intersections, which may be in the comparison group Sample sizes of locations and thus critical crash types are small in any city/county Changes in exposure between Before and After Differences in crash reporting between cities Possible “hidden” effects of changes in yellow interval with RLC installed Definitions of “red-light crashes”

Would Like to Know: Effects at treated intersections Spillover effects at other intersections Effects of RCL sign location (at intersection or not) Effects of publicity campaign Effects of ticketing policy (e.g., owner vs. driver ticket with points) Effects of RLC plus signal timing (e.g., yellow interval changes, all-red intervals Economic effects of RLC -- $$ saved

Study Phases Phase I – develop evaluation design – Completed 7/1/02 Phase II – conduct evaluation – Initiated 10/1/02 – Expected completion 5/1/04

Phase I: Study Design Critical review of literature – What is known – What problems must be overcome Work with oversight panel to determine major study questions and basic design issues – FHWA Safety R&D and FHWA ITS JPO – Mike Griffith, Chair

Phase I: Study Design (cont) Interviewed 15 local agencies to determine data availability Chandler, AZ Prince George’s County, MD Fairfax Co., VA El Cajon City, CA Montgomery County, MD New York City, NY City of San Diego, CA San Francisco, CA Boulder, CO Sacramento City, CA Charlotte, NC Arlington Co., VA Howard Co, VA Baltimore, MD Greensboro, NC

Phase I: Study Design (cont) Agencies chosen for study – Howard Co., MD – Baltimore Co., MD – Charlotte, NC – San Diego, CA – San Francisco, CA – Montgomery Co., MD – El Cajun City, CA

Phase I: Study Design (cont) Basic design method – Retrospective before/after studies in each agency – Control for major biases using Empirical Bayes methods – Use of unsignalized intersections from same city and signalized from other cities in reference group – Aggregate results across agencies – Separate out effects of signal timing, ticketing, signage, publicity, etc. if possible

Phase I: Study Design (cont) Quantifying economic benefits of RLCs from a medical perspective – Attempt to combine Police crash data from from Charlotte, NC Hospital data from Charlotte “Cost of crash” data from NHTSA/FHWA – Difficulty – cannot just use hospital data since it misses both fatalities and minor injury shifts – Directed to do a feasibility study first

Phase II: Study Implementation Initiating data collection now Major data difficulties expected – Lack of computerized data in city/counties – Lack of intersection geometrics for non-RLC sites – Lack of annual traffic count data – Lack of “signal timing” and “intersection- change” data in some cities