Perform robust observations at intersections before determining whether red-light cameras should be installed.
Understanding whether red-light cameras would be a useful in the first place.
Made Public Date


United States

Evaluating the Impacts of Red Light Camera Deployment on Intersection Traffic Safety


Red Light Cameras (RLCs) are a popular measure to reduce red-light running and improve intersection safety. However, they may not always be effective, and their impacts on broader driver behavior are not fully determined. The objective of this report was to assess the effectiveness of RLC systems in reducing various types of intersection crashes and the impact of RLC systems on driver behaviors such as approaching speed and responses to yellow signal phases.

To perform this analysis, researchers evaluated the effectiveness of RLC deployments at 27 different intersections across Maryland. They also directly investigated the impact of RLCs on driver behaviors by performing empirical observations at two RLC intersection clusters and analyzed the results to determine responses to the presence of RLCs.

Findings were classified into four categories: Reduction in both side-impact crashes and rear-impact collisions; reduction in side-impact crashes only; reduction in rear-end collisions only; and no influence on rear-end collisions.

When analyzing the effectiveness of the selected 27 RLC deployments, researchers looked at six different time spans: every combination of either three or five years before and after implementation. This was to ensure robustness.

Lessons Learned

From their investigations, the authors had a list of recommendations for agencies choosing to implement RLC systems:

  • Agencies should follow the development guidelines published by FHWA, only using RLCs as a "last resort."
  • Agencies should develop effective deployment guidelines to account for behavioral discrepancies among driving populations and locality-specific constraints.
  • Agencies should perform observations of vehicle approaching speeds at candidate-RLC intersections, in particular noting the percentage of aggressive drivers.
  • Agencies should implement safety strategies at intersections with high percentages of aggressive drivers in order to increase the probability of a successful RLC deployment.
  • Agencies should perform extensive field observations at both RLC and non-RLC intersections to develop guidelines and design control strategies.