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Auto and Road User Journal
March 17, 1997
TranSafety, Inc.
(U.S. and Canada)
(360) 683-6276
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Highway Safety Publications Catalog. Articles on Road Engineering, Road Maintenance & Management, and Injury Litigation. Information and consulting for the Automobile and Road User, as well as for law professionals in accident investigations.
TranSafety's free consumer journal for automobile and road users, three subscription journals on road maintenance, engineering, and injury litigation, and highway safety publications catalog. See our free consumer journal for automobile and road users, three subscription journals on road maintenance, engineering, and injury litigation, and a highway safety publications catalog.

Photo Radar Slows Speeders: Ontario Publiches Results of Four-Month Preliminary Study

In a January 1995 report entitled Photo Radar Safety Evaluation--Preliminary 4- Month Speed Results (SRO-95-101), the Safety and Regulation Division of the Ontario Ministry of Transportation (MTO) shared conclusions suggested by the first four months of data from a planned two-year study of the effects of photo radar on highway safety.


Ontario statistics for 1993 showed that 228,834 highway crashes resulted in 1,135 deaths and 91,174 injuries. The MTO estimates that crash-related emergency services, health care, property damages, lost earnings, and related human consequences represent an economic loss to society of about $9 billion each year. This report proposed that one key to reducing crashes and their costs is changing the perception that highway injuries and fatalities are the result of uncontrollable accidents. According to the report, accidents are collisions, and motorists can positively or negatively affect the number and severity of these collisions by changing their driving behavior.

The government of Ontario has developed the Integrated Safety Project to address safety issues related to the transportation and justice systems. Through education, media coverage, and increased enforcement, the MTO has promoted initiatives to encourage seatbelt use, reduce drinking and driving, and increase awareness of dangerous aggressive driving behavior.

A pilot project to test the effect of photo radar on speed reduction and collision severity is a recent initiative in the Integrated Safety Project. Photo radar units take pictures of speeding vehicles and record their license plate numbers. As a result of the photographs, vehicle owners receive tickets in the mail. Roadside signs and extensive media coverage make motorists aware of the use of photo radar surveillance.

While the evaluation of the initiative will continue for at least two years, this report published only data gathered during the month before the use of photo radar began and for the first four months of operation. The report addressed data on speed reduction but did not present findings on collisions. Due to the size of the sample and the depth of analysis necessary, the MTO will not publish results of crash data until at least a year into the study. The MTO, however, believes they will reduce crash severity by reducing highway speeds. The report mentioned several previous studies that support this belief.


Studies in British Columbia, Australia, and Texas confirmed a relationship between the use of photo radar and speed reduction. A 1988 Victoria, B.C. study concluded that photo radar cameras reduced speeds at study sites. Two years of data from Victoria, Australia showed that speed reduction at camera sites was greater when media publicity and signs announced the presence of photo radar. In Vancouver, B.C. research from a short-term 1994 study indicated that fewer vehicles traveled over the speed limit when photo radar was in place. Finally, an Arlington, Texas report concluded that the presence of photo radar cameras reduced speeding--the greater the concentration of cameras, the greater the reduction in speeders.

Sweden, Germany, and Australia reported decreases in injury-producing collisions with the introduction of photo radar. During a 1990-to-1992 Swedish research project, data showed fewer injury-producing crashes both on test roadway sections monitored by cameras and on control sections of roadways not monitored by cameras. The reductions were greater, however, where there were cameras. German statistics compared collisions on the Autobahn in 1977, without photo radar, and in 1978, after the installation of photo radar. Researchers reported increased compliance with speed limits. Moreover, there were only 9 crashes, 7 injuries, and no deaths in 1978 compared with 300 crashes, 80 injuries, and 7 deaths the year before. Similarly, Australian statistics from 1992 and 1993 showed photo radar reduced injury-producing collisions on some roadways by as much as 20 percent.

United States research substantiated the relationship between reduced speed and injury-producing collisions. In 1974, the U.S. instituted national 55-mile-per-hour speed limits. The Transportation Research Board estimated that during 1983 the reduced speed limit saved between 2,000 and 4,000 lives. Interstate highways where states increased the speed limit from 55 to 65 miles per hour experienced a 27.1 percent increase in fatal crashes in 1987, while sections of the interstate where the speed limit remained at 55 miles per hour showed increases of only 0.6 percent. During the same time, the number of motorists driving more than 65 miles per hour increased by 48.2 percent on interstates where the speed limit was 65 miles per hour; interstates where the speed limit was still 55 miles per hour showed an increase of only 9.1 percent. Michigan statistics compared fatalities, serious injuries, and moderate injuries on sections of interstate before and after the change from a 55-mile-per-hour speed limit to 65 miles per hour. Although no significant increase in the number of vehicles involved in crashes resulted, significant increases occurred in the number of fatalities and injuries--showing a relationship between higher speed and severity of crashes.

The MTO pointed out that increased speed increases stopping distance and results in more collisions, injuries, and fatalities. Figure 1 from the report shows the relationship between stopping distance and speed for a vehicle with good brakes on a straight, dry, level road.

In addition, crashes that occur at higher speeds involve greater transfer of energy upon impact and are more likely to result in severe injury or fatality. According to the report, a 1984 Transportation Research Board paper stated that an increase in impact speed from 64 km/h [40 mph] to 80 km/h [50 mph] roughly doubles the probability of fatal injury.


In an eleven-month pilot study, the Province of Ontario is using four portable photo radar units on selected sections of roadway. The MTO created three site pairings to compare data for test sections using photo radar equipment and control sections not using the equipment. Describing the roadway sections selected, the reported said:

The first set of site pairings [is] on a 6 lane, 100 km/h [62 mph] divided freeway with urban commuter traffic. The second pairing is a 4 lane, 100 km/h [62 mph] divided highway with recreational traffic. The third site is a 2 lane, 80 km/h [50 mph] undivided highway with urban commuter traffic.

Loops embedded in the roadways collected data 24 hours a day and seven days a week on vehicle speeds and sizes. Photo radar vehicles containing radar units, cameras, and Ontario Provincial Police patrolled the test roadways. Baseline data collection took place the end of July 1994. From August 1 through August 14, 1994, signs reading SPEED ENFORCED BY PHOTO RADAR confronted motorists on the test sections; however, enforcement did not begin until August 15.


With 18 million vehicles monitored on test roadways and 13 million on control roadways, results showed speed reductions on all roadways. However, the average speed reduction was greater at all test sites when compared with control sites. Table One from the report compared speeds at the various sites during the time periods of the study.

Data led researchers to several conclusions:

  • While the proportion of speeding vehicles decreased at all sites during the test period, decreases were greater at test sites.

  • The greatest decreases in the proportion of speeding vehicles at all sites were for vehicles traveling at the highest rates of speed. Again, the largest decreases were at test sites.

  • Substantial speed reductions at all sites suggested that media coverage of the use of photo radar at some sites affected the behavior of all drivers. In addition, other ongoing safety initiatives were probably causing speed reductions.

  • The greatest speed reductions occurred on the six-lane test section. While daily radio announcements advertised the use of photo radar at the six-lane site, the use of radar at other sites attracted less media attention. The report theorized, These preliminary data seem to support the hypothesis that specific speed enforcement in conjunction with public media campaigns can lower average speeds and the proportion of speeders on provincial highways.

  • At least for a short time, the mere presence of signing announcing photo radar reduced speeding--even when cameras were not present.

  • When the MTO increased enforcement presence and fully deployed the photo radar units (on December 1, 1994), decreases in speeding on the test roadways became even more significant. The report suggested that drivers were more likely to reduce their speed as they talked to more people who had seen the photo radar units or as they saw units themselves.

Based on preliminary data and emphasizing that more work lies ahead, the report expressed a reasonable expectation that the above mentioned changes in driver behaviours will eventually lead to a reduction in fatalities, severity of injuries and perhaps the number of collisions. . . . Baseline data showed 62 percent of motorists drove over the speed limit before photo radar enforcement. During the fourth month of enforcement, this figure had dropped to 47 percent at some sites. Over half the total drivers, however, continued to exceed the speed limit--even at the end of the preliminary study period.

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