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Red light cameras: a overview of the issue

By: Douglas Black

Date: Monday, 17. July 2006


Automated cameras have been posted by law enforcement officials in some intersections, with the intent of photographing, and ticketing, drivers who enter the intersection after the light has turned red. Some people hate that practice, and are crying foul, so the editors decided to tackle "red light cameras" in this article. Please add your thoughts in our discussion area.

The issues

There are several takes on using intersection, or "red light" cameras, but the points of the two main positions are:

The research

Red light running and the use of cameras is a complex issue, and difficult to crack. Don't be fooled by people offering simplistic answers-the verdict is still out on many aspects of this problem. And research on the cameras is relatively sparse compared to other aspects of driving and driver behavior.

The problem

As any driver knows, someone whizzing into an intersection when the light is red is a terrifying thing. If the cars facing the green light are already in the intersection, serious injuries and deaths often result. Figures in the USA for 2000 indicate that 106,000 crashes, 89,000 injuries, and about 1,036 deaths were attributed to red light running.

In fact, 96% of people fear getting hit this way. But, in typical contradiction, 56% of people admit to running red lights. 1

Who runs red lights?

So are these red light runners sociopaths? Or alien invaders cloned as humanoids? Well, according to the U.S. Federal Highway Administration, they are "drivers of all age, economic groups, and gender. The perpetrators are everyday people; professionals, blue-collar workers, unemployed, homemakers, parents, and young adults." A nationwide survey1 conducted in the summer of 1999 found that a typical offender has the following general characteristics:

Another study found that red light runners were more likely than other drivers to be male, have prior moving violations and DUI convictions, have invalid driver's licenses, and have consumed alcohol prior to the crash.2 They also appear to be less likely to wear seat belts.3

Fewer complaints? Maryland Senator Leonard Teitelbaum says that the number of complaints he hears about red light cameras has dropped to near zero. He thinks that with the increased awareness of aggressive driving, drivers have come to recognize cameras as the lesser of two evils.

One contributor to the Aggressive Driving Conference hosted by summarized a study 4 of Israeli drivers, which found that drivers were "more likely to run red lights at intersections with long red phases and more likely to be impatient and honk at intersections with shorter green phases."

Survey respondents in the U.S. generally believed that red light running goes unpunished and that police would catch fewer than 20% of the red light runners (actually an optimistic guess).5

Support for cameras

The crash statistics have been raised enough times that most people acknowledge that it is a big concern. Various surveys of people in the U.S. have found from 64 percent 6 to 75 percent 7 or more of people support the use of red light cameras, with even greater support from older respondents.8

How cameras work

Cameras have been used for traffic enforcement for over 30 years. "The first example ... reported in the research literature was the photo-radar on Autobahn A3 between Cologne and Frankfurt installed in May 1973." 9 Switzerland held trials of red light cameras in the 1970s, as did Texas, USA. Australia began using them in 1983, and New York followed in 1993. About 75 countries including many in Europe, the USA, Canada, and Mexico use photo enforcement of some kind. Some of the other countries are Austria, Belgium, Canada, Germany, Israel, the Netherlands, Singapore, South Africa, Switzerland, Taiwan, and the U.K.

In most places, the cameras are mounted on tall poles and are connected to the traffic signal. The cameras only receive power, or can only take pictures, when the light in question is red. Then, they allow a grace period-generally 0.3 seconds-for latecomers or those who stop late or are turning right. Buried under the pavement prior to the white "stop bar" are electromagnetic wire loops or piezoe sensors that sense when a vehicle is passing over them, and determine its speed. Typically, the cameras are set to only take pictures if the car is going 15 to 20 miles per hour (24 - 32 km). The first picture usually shows the car before it actually enters the intersection, but the light is already red. Then, a second (or 3rd or 4th) picture is taken showing the car in the middle of the intersection. The faster the car is going, the sooner the subsequent photos are shot. The camera records the date, time of day, and time elapsed since the beginning of the red signal and the speed of the vehicle onto either regular 35 mm film or digital devices. Electronic flashes help clear up images.

Various jurisdictions store the images in different ways, sometimes keeping them on a CDROM or hard drive in the camera box, sometimes uplinking them through phone lines to a central location, sometimes on actual film and so forth. (Some newer installations are all digital, and send the encrypted signals wirelessly to a remote location where they are processed. Partly, this depends on the manufacturers of the cameras. Then police can access the data on a secure Internet site for final decision making.) Normally, police officers or another appointee who is trained to examine the photos then reviews it and matches the license plate number with the owner's registration and mails out the ticket.

Now, let's get a few of things out of the way. You will not get ticketed for turning left on a red light after sitting in the intersection waiting for a gap that never appeared. Secondly, no ticket for you today if you came to a stop after creeping forward over the stop bar. Finally, the cameras do not take pictures if you entered the intersection on a yellow (amber) light, but it turned red while you were still moving on through. (However, note that different jurisdictions consider the intersection differently; some use the imaginary line extending from curb corners as the actual intersection, rather than the stop bar.)

Most communities have enacted legislation that allows for the rear of the car and its license plate to be photographed, not the driver. This means that the owner of the car gets the ticket, not necessarily the driver. It also means that points cannot be taken off the owner's license for a "moving violation," since there is no proof that he or she was behind the wheel (instead of the neighbor's dog). California, however, requires a photo of the driver; therefore, the cameras take a shot of the front of the car, too. Many of these are obscured by glare or dirty windshields and so on, so up to half of the violators are not sent tickets. San Francisco's staff found it best to print the photographs right on the citation. "Registered owners do not have to visit the court to view the photographs. People are less likely to tie up the court by contesting when they can see the photographs up front. San Francisco's program now provides four photographs on each citation: one of the vehicle entering the intersection, one of the vehicle clearing the intersection, a close-up of the driver's face, and a close-up of the license plate."

See the photos and animated graphics at HowStuffWorks.


Do red light cameras reduce the number of people running the light? Well, probably. Unfortunately, the hard research on this question is rather scant, in spite of long use in various countries, but there are a few studies that indicate some success. Estimates of the effectiveness range from 20-60% 10 to 35-60% in the Netherlands and Australia. 11 In a hearing before a federal government committee in July 2001, Judith Lee Stone, of Advocates for Highway and Auto Safety pointed to results in the U.K., where there was a 55 percent decline in violations, and to Singapore, which saw a 40 percent decline.

Two programs in the USA, in Oxnard, California, and Fairfax City, Virginia, were found to have reduced violations by about 40 percent during the first year of enforcement. 7 Other, more anecdotal reports from police bureaus and municipal governments offer praise of the systems used in certain cities. These are estimates for reductions in violations, or actual numbers of people running red lights.

Crash reduction

The other way to tell if cameras are useful is whether they reduce the actual numbers of crashes. Although more research is needed in this area, some evidence is emerging. The Advocates for Highway and Auto Safety state that "South Australia experienced over a 10 percent reduction in fatalities and a 24 percent reduction in injury crashes" because of red light camera introduction.

In the USA, the Federal Highway Administration reports the following results:

Internationally, the FHWA reports: "South Australia--10.4 percent reduction in fatalities and 24 percent reduction in injury crashes. Victoria, Australia--Right angle accidents decreased by 32 percent, right angle turning accidents decreased by 25 percent, rear end crashes decreased by 30.8 percent and rear end turning accidents increased by 28.2 percent." A researcher in Australia 12 examined the evidence for Melbourne intersection cameras, and concluded that the cameras "did not provide any reduction in accidents, rather there has been increases in rear end and adjacent approaches accidents on a before and after basis and also by comparison with the changes in accidents at intersection signals." However, he notes that most of the intersections had very low frequencies of violations to begin with, and thus are not a good test of the cameras' effectiveness.

So with the background of these few results, some of them mixed or tentative, a study in the USA, with different methodology, has recently been released. In this followup to a previous study, 8 the authors found significant overall crash reductions, citywide, after installing cameras in Oxnard, California. 13 "Injury crashes at intersections with traffic signals were reduced 29 percent after camera enforcement began in Oxnard in 1997. Front-into-side collisions--the crash type that's most closely associated with red light running--were reduced 32 percent overall, and front-into-side crashes involving injuries were reduced 68 percent."

Spillover effect

The research in Oxnard also found a spillover, or "halo" effect. Though just 11 of the city's 125 intersections had cameras, crash rates declined throughout the city. The authors conclude that "previous studies of red-light-running violations in Oxnard and elsewhere found similar spillover effects. That is, the violations dropped in about the same proportions at intersections with and without cameras, attesting to the strong deterrent value of red light cameras and their ability to change driver behavior."

Privacy concerns

Critics of red light cameras often express concerns that their use violates privacy rights. Let's look at some of the research on this subject-without getting caught up in legalese, and the complex and strange world of the law.

Less invasive? One person spoke to says he is not all that concerned about privacy issues. He figures that having police officers sitting on the side of road and pulling him over for running the light is equally invasive. The cameras are maybe less invasive feeling , since they are just robots, not judging, or asking questions about where he is going and came from and so forth. They're not peeking in the back of his car with a flashlight. He also sees cameras as helping remove the potential biases of police, such as toward blacks, or jalopies, or "boy racers" and so on.

Several researchers have stated that legal experts say that "automated enforcement does not violate a citizen's legal right to privacy." 10 14 Most countries or jurisdictions within a country pass legislation specifically to deal with the use of cameras, and many of these have been in place for decades. In the USA, one researcher 11 noted: "There is currently no court case which has specifically defined an individual's right to privacy under the First Amendment with respect to operating a vehicle." However, after reviewing prior rulings in related cases, he concludes that "because drivers are in the open view of the public when operating vehicles, the expectation of privacy has no basis. Therefore, the use of automated enforcement devices does not appear to violate any constitutional rights" (page J-8). He points to a 1958 ruling by the Supreme Court on a case involving police using an early form of photo radar. The court allowed the photo evidence to be admitted, and stated that "we have passed the horse and buggy days and are living in a new era. The question is, did the defendant do it and was there sufficient proof offered to find the defendant guilty beyond a reasonable doubt."

A more contemporary argument 7 was made in 2001: "Photographing vehicles whose drivers run red lights doesn't violate anyone's protected privacy interest. Most red light cameras record only the rears of vehicles, not vehicle occupants. Besides, driving is a regulated activity on public roads. Neither the law nor common sense suggests that drivers shouldn't be observed on the road or that their violations shouldn't be recorded."


"Typically, a change in state law is required before a local jurisdiction can use photo enforcement. This is because running a red light is a moving violation that must be observed by an officer. State laws decriminalize the offense by removing points charged against the driver's license.... In most states the owner of the vehicle is fined rather than the driver. The exceptions are Arizona, California, and Washington, D.C., where a photo of the driver is taken, and points are assigned to his or her license.15

Over 50 cities in the USA now use red light cameras.7 Many of these are in a few states that have enacted legislation. Automated enforcement has stood as valid evidence in many courtrooms,11 however, a 2001 case in California pointed to flaws in that state's legislation. A San Diego County Superior Court judge ruled that although the cameras were legal, the relationship between the private corporation that installed and managed the cameras and the police was improper. The corporation (a subsidiary of Lockheed Martin, which has since been bought by Affiliated Computer Services (ACS)), had too much involvement in the process according to the judge, and since its share of the ticket fee was tied to its own work, the relationship violated state law requiring greater separation.

Finally, in an effort to encourage tighter restrictions on the installation of red light cameras, the National Motorists Association, a lobby group for drivers, has created a Model Red Light Camera Law.


The use of red light cameras is a hot topic among drivers, and it is not going away anytime soon. As more municipal police departments feel the crunch of debt reducing government budgets, more jurisdictions will be considering installing red light cameras. At least one writer15 has said that in the aftermath of the September 11th attacks in the USA officials are expecting more demand for camera systems of all kinds. However, keep in mind the comments by these researchers:14 "The ultimate success of automated enforcement will not rely on the technology so much as how the technology is applied and how transportation professionals interact with state and/or local legislators, local judiciary, and most importantly the public when implementing automated enforcement."

Here are some of the things we at think should be kept at the fore:

  1. Engineering solutions must be considered first for problem intersections.
  2. Revenue generation from cameras must be carefully monitored to reduce conflicts of interest. New ways of distributing the money should be examined.
  3. Police officers should have final say over citations, not employees of a private company, especially if that company shares in money from ticketing.
  4. Photos taken should be of the car, not the driver's face.
  5. Legislation allowing cameras should be clearly focused, and involve the public from the start.
  6. More research is definitely needed to provide clearer evidence on several questions:
    • How many are "failed to see" crashes vs. "chose to zoom" crashes?
    • Do cameras reduce the actual numbers of crashes?
    • What methods improve signal visibility?
    • Why do drivers run red lights in different locales?
    • How can we train drivers to use better tactics when approaching intersections?
    • How do vision and perception problems contribute to failing to see the signal?
    • What are the best models for signal timing, including the all-red phase?

So let's send out a call to all researchers. The sooner they get started examining these issues, the better.

This overview of the issue is an article in transition, and we will update it every few months, or as developments warrant, so bookmark this page and stay tuned.


Here are the sources cited above. Many of them link to the full document on the Internet. For further reading, see the large bibliography on Automated Enforcement by Turner, S. (below).

1. Porter, B., & Berry, T. (1999). A nationwide survey of red light running: Measuring driver behaviors for the "Stop Red Light Running Program" . Norfolk, VA: Old Dominion University, Behavioral Community Psychology for the DaimlerChrysler Corporation, the American Trauma Society, and the Federal Highway Administration. [Electronic version]. Retrieved December 2001, from fourthlevel/pdf/OldDomStdy.pdf

2. Retting, R., Ulmer, R., & Williams, A. (1999). Prevalence and characteristics of red light running crashes in the United States. Accident Analysis and Prevention, 31 (6), 687-694.

3. Porter, B., & England, K. (2000). Predicting red-light running behavior: A traffic safety study in three urban settings. Journal of Safety Research, 31 (1), 1-8.

4. Shinar, D. (1998). Aggressive driving: The contribution of the drivers and situation. Transportation Research. Part F: Traffic Psychology & Behaviour, 1 (2), 137-160.

5. Porter, B., & Berry, T. (2001). A nationwide survey of self-reported red light running: measuring prevalence, predictors, and perceived consequences. Accident Analysis and Prevention, 33 (6), 735-741.

6. Lieb, R., & Wiseman, F. (2001). Public attitudes toward automobile safety issues. Transportation Journal, 40 (3), 26-32.

7. Retting, R. (2001, June 12). Red light violations and red light cameras . Statement before the Ohio House of Representatives, Transportation and Public Safety Committee. [Electronic version].

8. Retting, R., Williams, A., Farmer, C., & Feldman, A. (1999). Evaluation of red light camera enforcement in Oxnard, California. Accident Analysis and Prevention, 31 (3), 169-174. [Electronic version].

9. Sagberg, F. (2000). Automatic enforcement technologies and systems . (Working paper 7, RO-98-RS.3047 of the Escape Project). Technical Research Center of Finland. [Electronic version].

10. Federal Highway Administration. (1999). Synthesis and evaluation of red light running electronic enforcement programs in the United States (Report number FHWA-IF-00-004). Washington, DC: FHWA. [Electronic version].

11. Passetti, K. (1997). Use of automated enforcement for red light violations (Report for the graduate summer course CVEN 677 Advanced Surface Transportation Systems at the Texas A&M University). [Electronic version].

12. Andreassen, D. (1995). A long term study of red light cameras and accidents (Report number ARR 261). Vermont, Australia: Australian Road Research Board. [Electronic version].
Summary retrieved February 2002, from

13. Retting, R., & Kyrychenko, S. (2001). Crash reductions associated with red light camera enforcement in Oxnard, California . Arlington, VA: Insurance Institute for Highway Safety. [Electronic version].

14. Turner, S. & Polk, A. (1998). Overview of automated enforcement in transportation. ITE Journal , (June), 20-27. [Electronic version].

15. Welsh, W. (2001, November 5). Red-light cameras get a green light. Washington Technology, 16 , (16) [Electronic version].

Other useful references

Milazzo, J., Hummer, J., & Prothe, L. (2001). A recommended policy for automated electronic traffic enforcement of red light running violations in North Carolina . North Carolina Governor's Highway Safety Program. [Electronic version]. Retrieved March 2002, from

Office of the Majority Leader, U.S. House of Representatives (2001). The red light running crisis: Is it intentional? Washington, DC: Author. [Electronic version].

Retting, R., Chapline, J., & Williams, A. (2002). Changes in crash risk following re-timing of traffic signal change intervals. Accident Analysis & Prevention, 34 (2), 215-220.

Federal Highway Administration. (2000). Association of selected intersection factors with red-light-running crashes (Report number FHWA-RD-00-112). Washington, DC: FHWA. [Electronic version].

Retting, R., & Williams, A. (1996). Characteristics of red light violators: results of a field investigation. Journal of Safety Research, 27 (1), 9-15.

Retting, R., Williams, A., & Greene, M. (1998). Red light running and sensible countermeasures: Summary of research findings. Transportation Research Record, 1640 , 23-26. [Electronic version].

Datta, S., Datta, TK., & Schattler, K. (2000). Red light violations and crashes at urban intersections. Transportation Research Record, 1734 , 52-58.

Turner, S. (nd). Automated enforcement bibliography . Washington, DC: ITE Automated Enforcement Technical Committee. [Electronic version].

Labash, M. (2002, April 1). Inside the District's red lights. The Daily Standard . [Electronic version].

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All Comments (8)

Showing 1 - 8 comments

Frank Monteith,

The loops in the pavement, generally detect the front axle, not the front bumper or the engine. Vehicles with set back axles like buses and trucks, Corvettes, may have incorrect tickets.
Cars turning right, may stop prior to the loop, then proceed over the loop and be ticketed.
There are several things about red light cameras which may lead to false tickets.
The courts think that they are perfect, they are not!

Jim Johnson,

Red light photo enforcement comes down to big brother being a big bully.


I recently had a picture snapped at a red light camera. I actally looked up at the yellow light actually over my head and passed under the light which then turned red. Therefore, I take offense at the statement "Finally, the cameras do not take pictures if you entered the intersection on a yellow (amber) light, but it turned red while you were still moving on through." All man made equipment fail from time to time. I believe the timing is off. If I had not experienced it I would have agreed with you up to this point. It will be interesting to see if they have a before picture of my vehicle entering the intersection after the light turned red.


My town is getting 6 red-light cameras soon.
Of course it is to increase revenue, otherwise I feel things like the Yellow Light Interval, and Red-Light / Green-Light Lag time would have been studied & both possibly increased.
Things like road grade, weather conditions, and light/darkness can affect how people drive, and traffic light timing should be changed accordingly. Of course the argument that it costs money to re-time lights is used, but just what are computers for if we can't use them? These new Red Light camera systems are going to be computer operated from a central location, why can't traffic lights?
Also, at intersections where people become confused - ex. trying to turn left onto a Hwy that is Really Wide, people behind them get slowed down, frustrated, etc and maybe a ticket. Point being is that in these cases, better signage / lighting might direct confused drivers and keep traffic flowing.
I feel that severe accidents caused by idiotic drivers will still happen at camera monitored intersections, and these cameras will mainly be used to take money from people turning right on red without stopping.
Read the Federal Highway Admin Red Light Systems Operational Guidelines at:
There are many questions that should be asked, ideally before operations begin.


i know our constitution says we have a right to face our accuser in a court of law. how do we face the camera since it was the only one there when the photo was taken


your links don't work...


I got a ticket from the red light police... It did show a picture of my car at a "red light"??? However when I reviewed the evidence video on the internet as officially suggested by the police the video showed my car was in the intersection and the light was YELLOW not red??? After 25 minutes of telling the hearing office I was innocent while providing the "yellow light" picture she said sorry I have to find you guilty.


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I would like to become train driver in Holland, do you have any suggestion what is the procedure?


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