Benefit

Intersection-related crashes decreased 11 percent overall at signal controlled intersections in Texas after the installation of automated traffic enforcement systems.

Safety benefits realized by photographic traffic signal enforcement at intersections statewide in Texas.


June 2011
Texas; United States


Summary Information

The Center for Transportation Safety at the Texas Transportation Institute conducted an extensive study to determine the safety impact of automated traffic enforcement systems (red light running cameras) at intersections. The study examined more than 11,000 crash records of crashes that occurred in the state of Texas at 275 intersections before and after they had installed automated traffic enforcement systems. The analysis considered type of crash (right angle, rear-end and other types) and roadway characteristics.

METHODOLOGY

To evaluate the effectiveness of automated traffic enforcement systems at signal controlled intersections to reduce crashes, the Texas Transportation Institute conducted an extensive study of crashes at intersections statewide. The study compared the frequency and type of crashes that occurred at 275 intersections statewide where cameras were in place, encompassing 30 communities and a range of roadway types. Each of the communities’' intersections were paired into 1, 2 and 3 year data periods. All intersections and the crashes that occurred within them were evaluated and compared against like date range parameters. Researchers compared data from crashes at the intersections that occurred before and after installation of the cameras by analyzing over 11,000 crash records in the Crash Records Information System maintained by the Texas DOT (TxDOT). Comparison of total crashes from before/after time periods and selection of a subset of red light related crashes were used to measure effectiveness of the treatment.

FINDINGS

A total of 11,122 intersection-related crashes took place within the 275 intersections in the study. Of these, 5,869 crashes occurred before the installation of automated enforcement, and 5,253 occurred after installation, a decrease of 616 crashes, representing an 11 percent decline statewide.

Other results indicated:
  • 1 Year Group Intersections
    • Red light related crash frequency reduced by 23 percent after the activation of treatment.
    • Right angle crash frequency reduced by 19 percent after treatment.
  • 2 Year Group Intersections
    • Red light related crash frequency reduced 27 percent after the activation of treatment.
    • Right angle crash frequency reduced by 37 percent after treatment.
  • 3 Year Group Intersections
    • Red light related crash frequency reduced 21 percent after the activation of treatment.
    • Right angle crash frequency reduced by 26 percent after treatment.
  • Rear end collisions increased over 100 percent for all three years.
  • Reductions in crash frequency occurred across the board, at intersections on all types of roadway, including primary roads, farm-to-market roads, interstate access roads, state highways, and US highways.

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Source

Evaluation of Photographic Traffic Signal Enforcement Systems in Texas

Author: Walden, T.D.

Published By: Texas Transportation Institute, The Texas A&M University System

Source Date: June 2011

URL: http://tti.tamu.edu/documents/TTI-2011-4.pdf

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Goal Areas

Safety

Related Metropolitan Integration Links

Link 26: Arterial Management intra-component

Typical Deployment Locations

Statewide

Keywords

photo enforcement, red light cameras, red light running, automated enforcement, traffic signals, run red lights, RLR, red light runners, photo-red

Benefit ID: 2011-00660