Radar speed limit signs (also called “driver feedback signs”) prompt speeding drivers to slow down. The signs detect and display a speeding driver’s velocity. This active feedback makes drivers aware of their speed. It also makes them feel like they’re being monitored. The result: speeders slow down.
Some signs can collect traffic and speed data for use by traffic engineers and law enforcement. Radar speed limit signs are easy to install and inexpensive to operate. They can even run on solar power. They typically cost between $4,000 and $5,000. Some portable models — ones that can be attached to existing sign posts — cost only $2,700.
Click the graph at left to enlarge it. Radar speed limit signs prompt 35 to 70% of all speeding drivers to slow down. Tests show they reduce average speeds by 7 to 17% and increase speed limit compliance by 40 to 60%. Radar speed limit signs provide an effective traffic calming solution without the negatives associated with speed humps.
With support from the Governor’s Office of Highway Safety and the City of Dunwoody, PEDS asked Georgia-based sign manufacturer Radarsign to demonstrate the effectiveness of a driver feedback sign on North Peachtree Road, a street plagued by speedy drivers. The sign operated in “stealth” mode for a week and detected that more than half of all drivers were speeding. Then the sign was activated to display drivers’ speeds. During the next week, the active sign cut the total number of speeders by more than forty percent. The sign also slowed the fastest drivers on the road by nearly ten miles per hour and cut the number of drivers exceeding 40 mph by 50%. See the results and charts (PDF).
PEDS endorses radar speed limit sign technology, not a specific company. A local vendor is RadarSign, located in Alpharetta. They are working with several municipalities in Georgia to install signs in school zones and neighborhoods. PEDS has no affiliation with RadarSign and receives no financial support from them. You can contact RadarSign for information on pricing and planned installations.
Find out your city’s or county’s policy. In some municipalities, they allow these signs as long as the neighborhood pays for them. In other places, the city installs radar speed limit signs only in certain school zones. Call your city or county public works department and ask how you can get a radar speed limit sign installed.