Q&A: Red light cameras

April 2013

1 Why is red light running a problem?

Red light runners cause hundreds of deaths and tens of thousands of injuries each year. In 2011, 714 people were killed and an estimated 118,000 were injured in crashes that involved red light running. About half of the deaths in red light running crashes are pedestrians, bicyclists and occupants in other vehicles who are hit by the red light runners.

An Institute study of urban crashes found that those involving drivers who ran red lights, stop signs and other traffic controls were the most common type of crash (22 percent). Injuries occurred in 39 percent of the crashes in which motorists ran traffic controls.

Retting, R.A.; Williams, A.F.; Preusser, D.F.; and Weinstein, H.B. 1995. Classifying urban crashes for countermeasure development. Accident Analysis and Prevention 27(3):283-94.

Red light running crash

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2 How is red light running defined?

If a vehicle enters an intersection any time after the signal light has turned red, the driver has committed a violation. Motorists who are inadvertently in an intersection when the signal changes (waiting to turn left, for example) are not red light runners. In locations where a right turn on red is permitted, drivers who fail to come to a complete stop before turning may be considered red light runners. Violations also include people turning right on red at intersections where prohibited.

3 Are right turn on red violations dangerous?

Yes, especially for pedestrians and bicyclists. Studies conducted after states first adopted right-turn-on-red laws found that allowing right turns on red increased pedestrian and bicyclist collisions at intersections by 43-123 percent. Zador, P.L. 1984. Right-turn-on-red laws and motor vehicle crashes: a review of the literature. Accident Analysis and Prevention  16(4):241-5. Preusser, D.F.; Leaf, W.A.; DeBartolo, K.B.; and Blomberg, R.D. 1981. The effects of right-turn-on-red on pedestrian and bicyclist accidents, Report no. DOT HS-806-182. Darien, Connecticut : Dunlap & Associates, Inc.  An analysis of intersection crashes in four states found that right-turn-on-red crashes frequently involved pedestrians and bicyclists, and 93 percent of these crashes resulted in injuries to the pedestrians and bicyclists. National Highway Traffic Safety Administration. 1995. The safety impact of right turn on red: report to Congress. Washington, DC: U.S. Department of Transportation.

4 How often do drivers run red lights?

A study conducted during several months at five busy intersections in Fairfax, Virginia, prior to the use of red light cameras, found that, on average, a motorist ran a red light every 20 minutes at each intersection. Retting, R.A.; Williams, A.F.; Farmer, C.M.; and Feldman, A.F. 1999. Evaluation of red light camera enforcement in Fairfax, Va., USA. ITE Journal 69:30-4. During peak travel times, red light running was more frequent. An analysis of red light violation data from 19 intersections without red light cameras in four states found that 1,775 violations occurred over 554 hours for a violation rate of 3.2 per hour per intersection. Hill, S.E. and Lindly, J.K. 2003. Red light running prediction and analysis. UTCA Report no. 02112. Tuscaloosa, AL: University Transportation Center for Alabama.

 In a 2012 telephone survey by the AAA Foundation for Traffic Safety, 92 percent of drivers said it's unacceptable to go through a red light if it's possible to stop safely, but 38 percent reported doing so in the past 30 days. AAA Foundation for Traffic Safety. 2013. 2012 traffic safety culture index. Washington, DC.  In a 2011 Institute survey in 14 large cities with long-standing red light camera programs, 82 percent of drivers said they believed running red lights is a serious threat to their personal safety, and almost all (93 percent) said running red lights is unacceptable. Still, 7 percent of drivers said that they had driven through a light after it had turned red at least once in the past month. McCartt, A.T. and Eichelberger, A.H. 2012. Attitudes toward red light camera enforcement in cities with camera programs. Traffic Injury Prevention 13(1):14-23.

5 Which drivers are most likely to run red lights?

A 1996 Institute study of red light runners at one Arlington, Virginia, intersection found that, as a group, they were younger, were less likely to use safety belts and had poorer driving records than drivers who stopped for red lights. Red light runners were more than three times as likely to have multiple speeding convictions on their driver records. Retting, R.A. and Williams, A.F. 1996. Characteristics of red light violators: results of a field investigation. Journal of Safety Research  27(1):9-15.

In an analysis of drivers involved in 2011 fatal red light running multiple-vehicle crashes, the red light runners were more likely than other drivers to be male, younger, and to have prior crashes or alcohol-impaired driving convictions. The red light runners also were more likely to be speeding or alcohol-impaired at the time of the crash and less likely to have a valid driver's license.

6 What countermeasures help to reduce red light running?

Signalized intersections can be replaced altogether by roundabouts, which have dramatically fewer injury crashes. However, it's not feasible to replace every traffic light with a roundabout, and not every intersection is appropriate for a roundabout.

More information on roundabouts.

Providing adequate yellow signal time and a brief phase when all signals are red is important and can reduce crashes, but those things alone don't eliminate the need for or potential benefits of red light cameras. Studies have shown that increasing yellow timing to values associated with guidelines published by the Institute of Transportation Engineers Institute of Transportation Engineers. 1985. Determining vehicle change intervals: a recommended practice. Washington, DC: Institute of Transportation Engineers.  can significantly decrease the frequency of red light violations. Bonneson, J.A. and Zimmerman, K.H. 2004. Effect of yellow-interval timing on the frequency of red-light violations at urban intersections. Transportation Research Record 1865:20-7. Retting, R.A. and Greene, M.A. 1997. Influence of traffic signal timing on red light running and potential vehicle conflicts at urban intersections. Transportation Research Record 1595:1-7. Van Der Horst, R. 1988. Driver decision making at traffic signals. Transportation Research Record 1172:93-7.  In addition, a 2002 Institute study found that injury crashes at urban intersections fell 12 percent after the yellow and all-red traffic signal timing was modified according to ITE guidelines. Retting, R.A.; Chapline, J.F.; and Williams, A.F. 2002. Changes in crash risk following re-timing of traffic signal change intervals. Accident Analysis and Prevention 34(2):215-20.

These measures alone may not eliminate the need for enforcement of red light violations at some intersections. An Institute study conducted in Philadelphia evaluated effects on red light running of first lengthening yellow signal timing by about a second and then introducing red light cameras. Retting, R.A.; Ferguson, S.A.; and Farmer, C.M. 2008. Reducing red light running through longer yellow signal timing and red light camera enforcement: results of a field investigation. Accident Analysis and Prevention 40(1):327-33. While the longer yellow reduced red light violations by 36 percent, adding camera enforcement further cut red light running by another 96 percent.

7 How do red light cameras work?

Red light cameras automatically photograph vehicles whose drivers run red lights. The cameras are connected to the traffic signal and to sensors that monitor traffic flow just before the crosswalk or stop line. The system continuously monitors the traffic signal, and the camera captures any vehicle that doesn't stop during the red phase. Many red light camera programs provide motorists with grace periods of up to half a second after the light switches to red.

Red light camera violation

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Depending on the particular technology, a series of photographs and/or a video clip shows the red light violator prior to entering the intersection on a red signal, as well as the vehicle's progression through the intersection. Cameras record the date, time of day, time elapsed since the beginning of the red signal, vehicle speed and license plate. Tickets typically are mailed to owners of violating vehicles, based on a review of photographic evidence.

8 Do red light cameras reduce violations?

Yes. A series of Institute studies in different communities found that red light violations are reduced significantly with cameras. A 2012 Institute study in Arlington County, Virginia, found significant reductions in red light violations at camera intersections one year after ticketing began. Hu, Wen and McCartt, A.T. 2013. Effects of red light camera enforcement on red light violations in arlington county, virginia. Insurance Institute for Highway Safety. Arlington, VA. These reductions were greater the more time had passed since the light turned red, when violations are more likely to result in crashes.  Violations occurring at least 0.5 seconds after the light turned red were 39 percent less likely than would have been expected without cameras. Violations occurring at least 1 second after were 48 percent less likely, and the odds of a violation occurring at least 1.5 seconds into the red phase fell 86 percent.  At two nearby noncamera intersections on camera corridors, the odds of violations also were lower than would have been expected without the camera program but these results were not always statistically significant.  At two other noncamera sites in Arlington not on camera corridors, the odds of violations increased. The evaluation examined the first year of Arlington County’s red light camera program, which was modest in scope and without ongoing publicity. A larger, more widely publicized program likely is needed to achieve broad community-wide effects.

Earlier Institute studies in Oxnard, California, and Fairfax City, Virginia, reported reductions in red light violation rates of about 40 percent after the introduction of red light cameras. Retting, R.A.; Williams, A.F.; Farmer, C.M.; and Feldman, A.F. 1999. Evaluation of red light camera enforcement in Fairfax, Va., USA. ITE Journal 69:30-4. Retting, R.A.; Williams, A.F.; Farmer, C.M.; and Feldman, A. 1999. Evaluation of red light camera enforcement in Oxnard, California. Accident Analysis and Prevention 31(3):169-74. In addition to the decrease in red light running at camera-equipped sites, the effect carried over to nearby signalized intersections not equipped with red light cameras.

9 Do red light cameras reduce crashes?

Yes. A 2011 Institute study comparing large cities with red light cameras to those without found the devices reduced the fatal red light running crash rate by 24 percent and the rate of all types of fatal crashes at signalized intersections by 17 percent. Hu, W.; McCartt, A.T. and Teoh, E.R. 2011. Effects of red light camera enforcement on fatal crashes in large US cities. Journal of Safety Research 42(4):277-82.

Previous Institute research in Oxnard, California, found significant citywide crash reductions followed the introduction of red light cameras, and injury crashes at intersections with traffic signals were reduced by 29 percent. Retting, R.A. and Kyrychenko, S.Y. 2002. Reductions in injury crashes associated with red light camera enforcement in Oxnard, California. American Journal of Public Health 92(11):1822-5. Front-into-side collisions - the crash type most closely associated with red light running - at these intersections declined by 32 percent overall, and front-into-side crashes involving injuries fell 68 percent. 

An Institute review of international red light camera studies concluded that cameras lower red light violations by 40-50 percent and reduce injury crashes by 25-30 percent. Retting, R.A.; Ferguson, S.A.; and Hakkert, A.S. 2003. Effects of red light cameras on violations and crashes: a review of the international literature. Traffic Injury Prevention 4(1):17-23. The Cochrane Collaboration, an international public health organization, reviewed 10 controlled before-after studies of red light camera effectiveness. Aeron-Thomas, A.S. and Hess, S. 2005. Red-light cameras for the prevention of road traffic crashes. Cochrane Database of Systematic Reviews 2005, Issue 2, Art. no. CD003862. Oxfordshire, England: The Chochrane Collaboration. Based on the most rigorous studies, there was an estimated 13-29 percent reduction in all types of injury crashes and a 24 percent reduction in right-angle injury crashes.

10 Do red light cameras increase the risk of a rear-end collision?

Some studies have reported that while red light cameras reduce front-into-side collisions and overall injury crashes, they can increase rear-end crashes. However, such crashes tend to be much less severe than front-into-side crashes, so the net effect is positive.

A study sponsored by the Federal Highway Administration evaluated red light camera programs in seven cities. Council, F,; Persaud, B.; Eccles, K.; Lyon, C.; and Griffith, M. 2005. Safety evaluation of red-light cameras. Report no. FHWA HRT-05-048. Washington, DC: Federal Highway Administration.  The study found that, overall, right-angle crashes decreased by 25 percent while rear-end collisions increased by 15 percent. Results showed a positive aggregate economic benefit of more than $18.5 million in the seven communities. The authors concluded that the economic costs from the increase in rear-end crashes were more than offset by the economic benefits from the decrease in right-angle crashes targeted by red light cameras.

Not all studies have reported increases in rear-end crashes. The review by the Cochrane Collaboration did not find a statistically significant change in rear-end injury crashes. Aeron-Thomas, A.S. and Hess, S. 2005. Red-light cameras for the prevention of road traffic crashes. Cochrane Database of Systematic Reviews 2005, Issue 2, Art. no. CD003862. Oxfordshire, England: The Chochrane Collaboration.

11 Does someone review the photographs before motorists are ticketed?

Yes. It is standard practice for trained police officers or authorized civilian employees to review every picture to verify vehicle information and ensure the vehicle is in violation. A ticket is issued only if there is clear evidence the vehicle ran a red light. Eccles, K.A.; Fiedler, R.; Persaud, B.; Lyon, C.; and Hansen, G. 2012. Automated enforcement for speeding and red light running. National Cooperative Highway Research Program Report no. 729. Washington, DC: Transportation Research Board.

12 Do red light tickets affect driving records or insurance rates?

In most states, red light camera citations are issued to vehicle owners and treated as civil offenses rather than moving violations. This means that there are no driver license points assessed and no insurance implications. In some states, the law specifically prohibits insurers from considering red light camera citations in determining premiums or renewals. In a few states (Arizona, California, Illinois) red light camera citations are treated the same as citations issued by police officers doing traffic enforcement.

State laws and penalties for photo enforcement tickets

13 Do red light cameras violate motorists' privacy?

No. Driving is a regulated activity on public roads. By obtaining a license, a motorist agrees to abide by certain rules, such as to obey traffic signals. Neither the law nor common sense suggests drivers should not be observed on the road or have their violations documented. Red light camera systems can be designed to photograph only a vehicle's rear license plate, not vehicle occupants, although in some places the law requires a photograph of the driver.

14 Are special laws needed to allow localities to use red light cameras to cite violators?

Before cameras may be used, state or local laws must authorize enforcement agencies to cite red light violators by mail. The legislation makes the vehicle owner responsible for the ticket. In most cases, this involves establishing a presumption that the registered owner is the vehicle driver at the time of the offense and providing a mechanism for vehicle owners to inform authorities if someone else was driving.

Another option is to treat violations captured by red light cameras as the equivalent of parking tickets. If, as in New York, red light camera violations are treated like parking citations, the law can make registered vehicle owners responsible without regard to who was driving at the time of the offense.

Red light cameras currently are authorized in about half of U.S. states.

15 Which U.S. cities use red light cameras?

The number of communities using red light cameras has increased dramatically since the first camera program was implemented in 1992 in New York City. Currently, 528 U.S. communities have red light camera programs. Cities using red light cameras include Atlanta, Baltimore, Chicago, Denver, New Orleans, New York City, Philadelphia, Phoenix, San Francisco, Seattle and Washington, D.C., plus many other communities.

U.S. cities with red light cameras

Trends in the number of U.S. communities with red light camera programs

16 Does the American public support red light cameras?

Yes. Like other government policies and programs, camera enforcement requires acceptance and support among the public as well as elected officials. Some opponents of automated enforcement raise the "big brother" issue, and voters in a few cities have rejected cameras.

Still, acceptance of cameras always has been strong. A 2011 Institute survey in 14 big cities with longstanding red light camera programs found that two-thirds of drivers support their use. McCartt, A.T. and Eichelberger, A.H. 2012. Attitudes toward red light camera enforcement in cities with camera programs. Traffic Injury Prevention 13(1):14-23.  A 2002 nationwide survey sponsored by the National Highway Traffic Safety Administration found that 75 percent of drivers support red light cameras.  Royal, D. 2004. National survey of speeding and unsafe driving attitudes and behavior: 2002; Volume II: findings. Report no. DOT HS-809-730. Washington, DC: US Department of Transportation.

An IIHS survey of people who live in Washington, D.C., which has an extensive camera program, found that 87 percent of residents support red light cameras. Cicchino, J.B.; Wells, J.K.; and McCartt, A.T. 2013. Survey about pedestrian safety and attitudes toward automated traffic enforcement in Washington, D.C. Arlington, VA: Insurance Institute for Highway Safety.

17 Is the objective of red light camera programs to generate revenue?

The primary purpose of photo enforcement should be to improve traffic safety by modifying driver behavior. Guidelines published in 2012 by the National Cooperative Highway Research Program, funded by state departments of transportation and administered by the Transportation Research Board, recommend that money from citations be used to pay for the cameras, and any excess should go to other highway safety programs. The guidelines also recommend conducting a public information campaign to explain the dangers of red light running and how the camera program will work before activating the cameras. Eccles, K.A.; Fiedler, R.; Persaud, B.; Lyon, C.; and Hansen, G. 2012. Automated enforcement for speeding and red light running. National Cooperative Highway Research Program Report no. 729. Washington, DC: Transportation Research Board. Ideally, ticket revenue should decline over time as the cameras succeed in deterring would-be red light runners.