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Synthesis of Safety Research Related to Speed and Speed Management - Turner-Fairbank.. Page 14 of' 25 55 mi/h (89 km/h) speed limit. Aerial enforcement was found to be significantly more effective than radar in detecting and apprehending drivers who used radar detectors and CB radios to avoid being caught exceeding the speed limit. Radar and Laser Speed Monitoring Equipment Teed and Lund (1991) studied the relative effectiveness of police radar and laser speed monitoring equipment in a brief field trial; the researchers used the same four locations, alternating use of radar and laser speed guns over a 2-week study period. They found that laser guns were significantly more effective in identifying speeding motorists (41 citations per 1,000 vehicles, compared to 33 per 1,000 for radar). Perhaps more important, it was found that speeders identified under the laser enforcement condition were four times more likely to have a radar detector in their vehicles than those ticketed under the radar condition. In fact, most of the additional speeders caught by the laser guns were using radar detectors, and those vehicles tended to be traveling at the most extreme speeds. Automated Enforcement Automated enforcement systems combine radar or laser speed-measuring technology and video or photographic identification to automatically detect and record speed limit violations. Radar or infrared laser instruments detect a speeding vehicle and trigger a pre-positioned camera to photograph the vehicle's license plate and the driver. The time of the violation and recorded speed of the vehicle are superimposed on the photograph. If the license plate number and driver can be clearly identified in the photograph, a citation is issued and mailed to the registered owner. Maekinen and Oei (1994) reviewed the effects of automatic enforcement on speeding, red-light violations, and crashes. They provide technical and tactical guidelines and stress that publicity and warning signs contribute significantly to the effectiveness of the technology. Rogerson et al. (1994) examined the effect of a speed camera program in Melbourne on the speeds of motorists and on the incidence and severity of crashes. A statistically significant reduction was found in casualty crashes within 1 km of a speed camera. The effect was confined to "high alcohol hours" of the week on ar[erial roads; there was no evidence of a difference in crash severity. It was reported that, following the introduction of the speed camera, the percentage of vehicles exceeding the speed limit by more than 15 km/h decreased and remained at a lower level in both 60 km/h and 75 km/h speed zones. No significant change in the mean speed was detected, and the distribution of vehicle speeds recorded in 100 km/h speed zones did not change. Drone Radar Freedman, Teed and Migletz (1993) evaluated the impact of unattended radar transmitters deployed in a construction zone to spoof motorists with radar detectors. Drone radar was associated with a slight reduction in average vehicle speed--an average reduction of one mile per hour or less. However, the proportion of vehicles exceeding the speed limit by more than ten miles per hour through the zones was reduced by 30 to 50 percent during active drone radar enforcement. A similar study by Streff, et al. (1995) examined the effectiveness of drone radar and police presence on the reduction of speeds at a high speed freeway location and in a freeway construction zone. They also found that speed reductions due to the drone radar deployment were of little practical significance. They did find that drone radar with police patrols can be an effective deterrent at locations where high speed trucks are a problem. Speed Feedback Indicators A speed feedback indicator displays the speeds of passing cars on a variable message display. The speed indicator is often trailer mounted below a speed limit sign. Speeds may be measure by an integrated radar or Iidar unit or by sensor in the pavement for permanent installations. Speed indicators are intended to increase awareness of excessive speeds and to encourage drivers to slow down. http://www.ntl.bts.gov/ntl/DOCS/speed/speed.htm 07/19/2000