How Effective Are Radar Speed Signs?

How effective are radar speed signs in calming traffic? Studies have proven that slowing traffic down will greatly reduce the chances of a fatal accident involving pedestrians and automobiles. A pedestrian hit by a car at 40 mph has a 90% fatality rate; at 20 mph the fatality rate decreases to 10%. As you can see in the graph below, just a small reduction in speed has a dramatic effect on whether those involved live or die.

Fatality rate for pedestrians hit by vehicles at different speeds

Radar speed signs are a proven traffic calming solution to raise the speed awareness of oncoming drivers. Studies repeatedly show that when alerted by a radar sign, speeders WILL slow down up to 80% of the time. Typical average speed reductions are 10-20%, and overall compliance with the posted speed limit will increase by 30-60%. Radar signs are particularly effective at getting “super speeders”—speeders driving 20 mph or more over the posted speed limit—to slow down.

The charts below demonstrate the effectiveness of radar speed signs with historical data and the resulting impact from actual radar sign locations:

All data collected with StreetSmart Traffic Data Collection and Reporting software.

Decline in Average Speeds

After 21 months of operation, the radar speed sign continues to be effective
in reducing the average speeds in a 25 MPH neighborhood cut-through street.

Average Vehicle Speeds: By MPH Segments
Raising Speed Awareness  with Radar Speed Signs -sample data report

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Shift of Peak Speeds to Lower Speeds

Six months of operation of a radar speed sign on a neighborhood cut through street demonstrates the effectiveness of the sign in lowering peak speeds to lower speeds.

Peak Speed Shifts: By MPH Segments
Raising Speed Awareness  with Radar Speed Signs -sample data report

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Speed Limit Compliance At Plant Entrance

1.5 years of radar speed sign operation at a plant entrance shows 55% more vehicles obeying the posted speed limit (PSL).

Radar Sign Reduces Speeding At Plant By 55%!
Raising Speed Awareness  with Radar Speed Signs -sample data report

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Long Term Reduction In Speeding Drivers

2 years of radar speed sign operation on a 40 MPH arterial street shows consistent, long-term reduction of speed.

Percent of Vehicles Speeding
Raising Speed Awareness  with Radar Speed Signs -sample data report

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Long Term Reduction In Average Speeds

2 years of radar sign operation on a 40 MPH arterial street shows average speeds maintain drop of 3.5 MPH.

Weekly Average Speeds
sample data report

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