Question: Do studies show that there are safety benefits from installation of these cameras systems? Do rear-end collisions increase when red-light cameras are installed—in which case, aren't we just trading one type of crash for another?
ANSWER: Analysis of data in the most comprehensive study to date (Safety Evaluation of Red-Light Cameras, FHWA HRT-05-048, April 2005) from seven jurisdictions (Baltimore; Charlotte; El Cajon, CA; Howard County, MD; Montgomery County, MD; San Diego; San Francisco) at 132 intersections using red-light cameras found:
A 25 percent decrease in total right-angle crashes;
A 16 percent decrease in injury right-angle crashes;
A 15 percent increase in total rear-end crashes; and
A 24 percent increase in injury rear-end crashes.
An economic analysis was conducted to assess the extent to which the increase in rear-end crashes negates the benefits for the decrease in right-angle crashes. This analysis, which was based on an aggregation of rear-end and right-angle crash costs for various severity levels, showed that red-light camera systems do indeed provide a modest aggregate crash-cost benefit. Economic analysis showed that red-light cameras saved society $39,000 to $50,000 annually at each intersection where they are installed. (The costs considered include: hospital bills, property damage to vehicles, insurance expenses, value of lost quality of life, and other costs.)
Primary factors for the greatest economic benefits for red-light camera installation include: locations where there are relatively few rear-end crashes and many right-angle ones, higher proportion of entering average annual daily traffic (AADT) on the major road, shorter cycle lengths and intergreen periods (yellow clearance and all-red), and one or more left-turn protected phases.
A survey conducted by NCHRP found that a majority of jurisdictions (including Boulder, CO; Polk County, FL; Mesa, AZ; Sacramento, CA; Laurel, MD, and others) reported downward trends in red-light running crashes and violations because of red-light cameras. See Impact of Red-Light Camera Enforcement on Crash Experience: A Synthesis of Highway Practice, NCHRP Synthesis 310 (Transportation Research Board, 2003) for more information. This report examines the impact of red-light running camera enforcement on crashes and related crash severity at intersections. The published research reviewed in this report indicates that red-light running automated enforcement can be an effective safety countermeasure.