Cameras can catch cars that run red lights, but that doesn’t make streets safer

by Justin Gallagher, Case Western Reserve University, The Conversation, August 15, 2018  (Creative Commons 3.0)

The automobile is a killer. In the U.S., 36,675 people died in traffic accidents in 2014. The year before, 2.3 million people were injured in traffic accidents.

During the past decade, over 438 U.S. municipalities, including 36 of the 50 most populous cities, have employed electronic monitoring programs in order to reduce the number of accidents. Red light camera programs specifically target drivers that run red lights.

In a study I co-authored with economist Paul J. Fisher, we examined all police-recorded traffic accidents for three large Texas cities over a 12-year period – hundreds of thousands of accidents. We found no evidence that red light cameras improve public safety. They don’t reduce the total number of vehicle accidents, the total number of individuals injured in accidents or the total number of incapacitating injuries that involve ambulance transport to a hospital.

Red light cameras

In a red light camera program, a camera is installed in a location where it can take photos or video of vehicles as they pass through the intersection. City employees or private contractors then review the photos. If a vehicle is in the intersection when the light is red, then a ticket is sent to the person who registered the vehicle.

These programs aim to reduce cross-street collisions. The idea is that drivers, fearing a higher chance that they will be fined, will be more likely to stop, lowering the number of angle, or “T-bone,” accidents.

Evidence clearly shows that camera programs are effective at decreasing the number of vehicles running red lights. In one study in Virginia, red light cameras reduced the number of total drivers running red lights by 67 percent.

However, cameras can have contradictory effects on traffic safety. Some drivers who would have otherwise continued to proceed through the intersection when the light is yellow or red will now attempt to stop. That means that the number of accidents caused by vehicles not stopping at a red light will likely decrease.

But the number of accidents from stopping at a red light – such as rear-end accidents – is likely to increase. That’s not an inconsequential side effect. Some drivers will attempt to stop, accepting a higher risk of a non-angle accident like getting rear-ended, in order to avoid the expected fine.

The overall effect of a camera program on vehicle accidents and injuries depends on the net impact of these two effects. Overall driver safety could increase or decrease.

Our study

In our study, we focused on Houston, a major U.S. city that operated a large camera program at 66 intersections between 2006 and 2010.

One reason we chose Houston is to take advantage of the natural experiment that occurred when city residents passed a referendum in November 2010 to ban the cameras.

We accessed detailed accident information on every traffic accident in Texas from 2003 to 2014 through a public records information request. The data included the accident’s precise geocoded location; the type of accident; whether the driver ran a red light; and details on any injuries.

When the Houston cameras were removed, angle accidents increased by 26 percent. However, all other types of accidents decreased by 18 percent. Approximately one-third of all Houston intersection accidents are angle accidents. This suggests that the program’s drawbacks canceled out its benefits.

Our study showed no evidence that cameras reduce the total number of accidents. We estimate that total accidents are reduced by a statistically insignificant 3 percent after the cameras are turned off.

Likewise, there’s no evidence that the camera program reduced the number of traffic-related injuries or the likelihood of incurring an incapacitating injury.

The elevated number of traffic accidents at urban intersections is a serious public health issue. But our study shows that Houston’s camera program was ineffective in improving traffic safety. Electronic monitoring is not the solution.

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Red Light Camera Studies

From Motorists.org

The preponderance of independent research (in other words, research that was not funded by ticket camera vendors or units of government interested in justifying camera-based traffic enforcement) has illustrated that ticket cameras typically increase, not decrease, the number of accidents at controlled intersections.

Case Western Reserve University, Gallagher and Fisher – Criminal Deterrence when there are Offsetting Risks: Traffic Cameras, Vehicular Accidents, and Public Safety
Red light cameras did nothing to improve safety during the years they were used in Houston, Texas. That was the conclusion of this 2017 study by Case Western Reserve University economist Justin Gallagher and Paul Fisher, a graduate student at the University of Arizona. Their paper covered twelve years’ worth of accident data at photo-enforced intersections in Houston and Dallas.

U.S. PIRG Red Light Camera Report – Caution: Red Light Cameras Ahead
According to this study by the national public interest advocacy group, U.S. PRIG, local governments hungry for revenue are signing contracts with red-light camera companies that put profit over traffic safety.

Camera Enforcement vs. Best Engineering Practices – The Clash of Diametrically Opposed Forces!
A presentation by Chad Dornsife, Executive Director, Best Highway Safety Practices Institute, at the 2002 Institute of Transportation Engineers District 6 meeting (with 2009 addendum).

Los Angeles Red Light Cameras Lead To Increased Accidents
A local TV station fact-checked the city’s claims that their ticket cameras reduced accidents and found that the opposite was true. At 20 of the 32 intersections studied, accidents increased and several intersections tripled their accident rate.

Virginia Accidents Increased After Ticket Camera Installation
The Virginia Transportation Research Council released a report expanding upon earlier research into the safety effects of red light cameras in Virginia. It showed an overall increase in crashes after cameras were installed.

A Long Term Study of Red-Light Cameras and Accidents
The conclusion of this Australian study was that RLCs are not an effective countermeasure and that they can increase the number of rear end crashes.

AAA Michigan Study Shows Cameras Aren’t Needed
AAA Michigan partnered with a number of communities to improve intersection safety. Their inexpensive structural changes resulted in a 47-percent decrease in crashes and a 50-percent decrease in injuries.

Red Light Running Cameras: Would Crashes, Injuries and Automobile Insurance Rates Increase If They Are Used in Florida?
A report published in Florida Public Health Review journal found that red light cameras increased accidents and insurance industry profit.

Red-Light-Running Behaviour at Red-Light Camera and Control Intersections
Monash University study showing red-light cameras have no effect on reducing violations.

A Detailed Investigation Of Crash Risk Reduction Resulting From Red-Light Cameras In Small Urban Areas
A study prepared by the North Carolina A&T State University found that red-light cameras increased the number of accidents at intersections.

A Response to Unfounded Criticisms of Burkey and Obeng (2004) Made by the IIHS
The North Carolina A&T University study above was criticized by the Insurance Institute for Highway Safety (IIHS). This is a rebuttal of IIHS’s claims by the authors of the North Carolina study.

Impact of Red-Light Camera Enforcement on Crash Experience — A Synthesis of Highway Practice
A recent study by the Transportation Research Board (TRB) illustrates the lack of evidence supporting the effectiveness of red-light cameras.

Evaluation of the Red-Light-Camera-Enforcement Pilot Project
This report from Ontario, Canada’s Ministry of Transportation’s concluded that jurisdictions using photo enforcement experienced an overall increase in property damage and fatal and injury rear-end collisions.

Development of Guidelines for Identifying and Treating Locations with a Red-Light-Running Problem
This Texas Transportation Institute study highlights the efficacy of increasing yellow-light times. An extra second yielded a 40-percent reduction in collisions.

Virginia DOT Study on Red-Light Cameras
The Virginia Department of Transportation released a biased report in favor of the cameras that still documented an increase in accidents, including more rear-end collisions and injuries.

Critique of IIHS 2001 Oxnard Study
California Senate Committee on Privacy critiqued the Oxnard study. The results show that IIHS’s study is flawed on many levels.

The Red-Light-Running Crisis: Is It Intentional?
This report was prepared by former House Majority Leader Dick Armey’s staff. It looks at the problems of red-light cameras and how to really deal with traffic-light violations.

Driver Behavior Characteristics at Urban Signalized Intersections
This study shows that providing adequate all-red clearance intervals can significantly impact intersection safety by reducing the probability of occurrence of right angle crashes, even if drivers run the red light.

Misleading San Diego Report
Although the report clearly credits the most significant reduction in violations to an increase in yellow time — a fact buried on page 78 — the report nonetheless credits these benefits to the red-light cameras everywhere else in the report, especially in the summary.

University of South Florida Criticism of Oxnard Study
University of South Florida researchers uncovered fundamental flaws in the first US study to claim red light cameras decrease accidents.

Report Critiques Red Light Camera Research Methods
A peer-reviewed article published in the Florida Public Health Review elaborates on the conclusion that red light cameras are associated with increased injury accidents.

RESOURCES: NMA Red Light Camera Fact Sheet ( PDF )