OLR Research Report

September 2, 2004




By: James J. Fazzalaro, Principal Analyst

You asked for general information on the use of cameras to enforce traffic violations at signalized intersections including in how many states such enforcement is currently used, what due process issues have been raised with respect to such systems, and what some of the results have been from using this type of photo enforcement.


Camera enforcement of red signal light violations at intersections is known to be in use in more than 100 municipal and county jurisdictions in 17 states, and in the District of Columbia. California and Maryland account for more than half of these jurisdictions. Besides the District of Columbia, the largest cities using photo red light enforcement include Phoenix, Los Angeles, San Diego, San Francisco, Chicago, Denver, and New York City, and Baltimore. In five states, camera enforcement is authorized on a statewide basis by statute. Several other states authorize it by law for specific communities or based on community-size. In six states, there are no authorizing laws but certain communities have adopted ordinances setting up camera enforcement.

Although there have been a number of court challenges to camera enforcement systems on constitutional grounds, including under the due process provisions of the Fifth and Fourteenth Amendments to the U.S. Constitution, no courts appear to have stuck down these programs based on these on constitutional grounds. However, some courts appear to have focused on some operational aspects of certain programs and invalidated citations in certain circumstances while upholding the validity of the programs in general. One area of concern raised by some courts is the practice of vendors operating the programs getting a portion of the fines paid by violators they are responsible for processing.

Proponents of red light camera enforcement point to a number of studies and self-reported results from many communities that identify declines in both intersection accidents and red light violations following institution of camera enforcement. Some of these studies also purport to identify a positive “spillover” effect of camera enforcement where accidents or violations also decline at intersections that are not equipped with cameras due to the increased public awareness that results from camera enforcement.

Camera enforcement opponents argue that some of these studies overstate the benefits of camera enforcement through bad study design or oversimplified analysis. They also argue that many communities implement these programs primarily for revenue enhancement rather than safety purposes. Finally, they point to studies that show similar improvements in accident and violation experience can be achieved by other means such as lengthening yellow light cycles or implementing short intervals during the signal cycles that give all sides a red light to allow for clearance of the intersection.


Photo enforcement of red light violations at signalized intersections is currently being used in over 100 communities in 17 states and the District of Columbia. California (35 communities and counties) and Maryland (22 communities and counties) represent the majority of locations currently using red light camera enforcement technology. North Carolina has the next most communities using cameras with 11. Some of the largest cities where red light camera enforcement is in use include Phoenix, Los Angeles, San Diego, San Francisco, Denver, Chicago, Baltimore, New York City, and the District of Columbia.

Camera enforcement is authorized on a statewide basis by statute in five states (California, Colorado, Delaware, Georgia, and Maryland) and the District of Columbia. In several other states, the law authorizes camera enforcement for cities of certain sizes (Illinois, New York and Oregon), certain specified cities (North Carolina), or even at certain specific locations in a city (Philadelphia, Pennsylvania). Oregon's law limits the use of photo enforcement to eight intersections for cities with 30,000 to 300,000 population and 12 intersections in cities of more than 300,000 population.

In several other states, there is no specific state law authorizing photographic red light enforcement but local ordinances provide for it in certain communities. These states include Arizona (Chandler, Mesa, Paradise Valley, Phoenix, Scottsdale, and Tempe), Ohio (Toledo and Dayton), South Dakota (Sioux Falls), Tennessee (Germantown), Texas (Garland), and Rhode Island (Providence).

The 35 jurisdictions in California using photo red light enforcement are: Bakersfield, Beverly Hills, Cerritos, Compton, Costa Mesa, Culver City, Cupertino, El Cajon, Fremont, Fresno, Fullerton, Garden Grove, Hawthorne, Indian Wells, Inglewood, Long Beach, Los Angeles City, Los Angeles County, Montclair, Montebello, Oxnard, Pasadena, Rancho Cucamonga, Redwood City, Sacramento City. Sacramento County, San Diego, San Francisco, San Juan Capistrano, Santa Ana, South Gate, Ventura, Upland, West Hollywood, and Whittier.

The 22 jurisdictions in Maryland using photo red light enforcement are: Anne Arundel County, Annapolis, Baltimore City, Baltimore County, Bel Air, Bladensburg, Bowie, Charles County, Cheverly, College Park, Cottage City, Forest Heights, Greenbelt, Howard County, Hyattsville, Laurel, Landover Hills, Montgomery County, Morningside, Prince Georges County, Riverdale Park, and Rockville.

Colorado has red light photo enforcement in Boulder, Denver, Fort Collins, and Northglenn. Delaware has it in Dover, Seaford, and Wilmington. Georgia has it in Decatur, Marietta, Rome, and Savannah. In North Carolina, photo enforcement is used in Cary, Charlotte, Fayetteville, Greensboro, High Point, Indian Trail, Marshville, Monroe, Raleigh, Rocky Mount, and Wilmington. Virginia has photo red light enforcement in Alexandria, Arlington, Fairfax City and County, Falls Church, and Vienna. Oregon law authorizes photo red light enforcement in Beaverton, Medford, and Portland.

Nevada law prohibits the use of photographic, video, or digital equipment unless it is hand held by a police officer or installed in a law enforcement vehicle.


The Fifth and Fourteenth Amendments to the U.S. Constitution require procedural safeguards against deprivation of life, liberty, or property without due process. Opponents of photo red light enforcement programs have challenged these programs on due process and other constitutional grounds in a number of states. The Insurance Institute for Highway Safety (IIHS), a proponent of automated traffic enforcement programs, maintains in its evaluation of the constitutional issues related to photo enforcement that every court that has reviewed automated enforcement programs has found that “using camera technology does not violate any provision of the U.S. or state constitutions; however, courts have required some cities to make changes in the programs to correct operational problems.” (Is Automated Enforcement Constitutional?, Shari T. Kendall, Insurance Institute for Highway Safety, May 2004, p. 1 (enclosed).

The report notes that state courts in California, Colorado, Oregon, and North Carolina, as well as the U.S. Ninth Circuit Court of Appeals, and the Superior Court of the District of Columbia have rejected challenges to the automated enforcement programs based on due process, equal protection, the Fourth Amendment protection against unreasonable search and seizure, and the “Takings Clause” of the Fifth Amendment.

The report also notes that although arguments regarding photo enforcement being an invasion of privacy and frequently made by opponents, no privacy challenges have been raised in court. It attributes this to the fact that the U.S. Supreme Court has clearly ruled that there is a lesser expectation of privacy while operating a motor vehicle than in other venues.

Some of the due process objections that photo enforcement opponents have made in these unsuccessful challenges include that: (1) not all drivers photographed receive tickets, (2) the vehicle owner is presumed to have been the driver at the time of the violation, (3) the laws do not specifically state where a warning sign should be, (4) there is a presumption that the driver committed the offense, and (5) the delay in receiving the ticket for the violation is too long.

One area in which some courts have expressed concern relates to the way in which vendors providing citation-processing services are paid. In many cases, photo enforcement programs are run for the governmental agencies by vendors. These vendors provide the camera systems to the local jurisdictions and in many cases process the photographic evidence and issue the citations to alleged violators. While some of these contracts provide the vendor a flat fee for services, some others give the vendor a portion of the fine that results from a conviction of the violation. Some courts have expressed concern over these “contingency” fees; viewing them as a potential conflict of interest for the private entity. This has been particularly controversial in San Diego where at least one court dismissed approximately 300 citations for this reason, although it found no constitutional problem with the existence of the program itself.


The National Highway Traffic Safety Administration maintains that in 2002, an estimated 920 people died in intersection accidents involving a driver that ran the red signal. It estimates that 178, 000 injuries also resulted from these crashes. The agency has initiated a “Stop Red Light Running” campaign to attempt to address the problem.

Most of the jurisdictions that have reported results of their red light photo enforcement programs have claimed reductions in violations, accidents, or both, although not necessarily at every intersection where photo enforcement has been used.

The IIHS conducted a review of the Oxnard, California program in 1999 which concluded that after the program's first year of operation, overall accidents had decreased by 7% and injury producing crashes declined by 29% at signalized intersections. Front-into-side crashes, which are the kind that are most frequently associated with red light violations, decreased by 32% overall and by 68% with respect to crashes that produced injuries. The study also found that red light running violations decreased by 42% across the city after cameras were introduced at only nine intersections—what the study concluded was a considerable “spillover” effect the cameras had on driver behavior generally.

Another IIHS study in Fairfax, Virginia found that red light running violations declined 44% the first year after camera enforcement began. The study noted a similar spillover effect as it had observed in the Oxnard study. The report found that the decline in violations at intersections that were not equipped with enforcement cameras was 34%. The study also found a 7% reduction in red light violations after three months of camera operation and a 44% reduction in violations after one year.

Several international studies conducted in Australia and Singapore have found injury accident reductions ranging from 7% to 46%, but the IIHS analysts noted some flaws in these study methodologies that do not control for certain statistical anomalies.

In some instances, the presence of red light enforcement cameras, while reducing angled crashes appears to have resulted in an increase in less severe rear-end collisions—apparently the result of drivers stopping rapidly to avoid going through the red signal. New York City has reported a 60-70% decline in angled crashes at one of its camera-equipped intersections. Considering all sites, the analysis concluded that rear end collisions held steady at most of the intersections and increased at some of them. New York City has also reported a 34% reduction in red light violations.

In Mesa, Arizona, a study conducted by the police department tracked six intersections for the period prior to installation of enforcement cameras (1995-99) and the period after installation (1999-2000). The report concluded that there was a 22% decrease in collisions caused by red light violators at these locations despite an increase in traffic volume and an approximate 18% increase in city population during this period.

Red light camera opponents generally argue that most cities using them are more interested in them for revenue enhancement purposes than as necessary safety measures. They also charge that many of the studies purporting to show safety benefits are methodologically flawed or not sufficiently rigorous. Opponents also point out that some analysts have shown that changing the signal cycles, in particular the cycle of the yellow signal, has the greatest effect on whether or not red light violations occur. Lengthening the yellow cycle, they argue, can eliminate many red light conflicts, thus eliminating the need for specialized enforcement applications such as red light cameras. One such study was conducted by AAA Michigan. The organization worked with Detroit city engineers to identify certain high crash intersections and certain countermeasures were devised. These included enlarging the traffic light lenses by 50%, remarking left turn lanes, retiming signals, and introducing an all-red clearance interval where all sides face a red signal for a brief period as the signals change. The AAA researchers reported a 47% decrease in accidents and a 50% reduction in injuries at the intersections that received the special enhancements.