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Neighborhood Traffic Management Program (NTMP)

Tools to Address Speeding

Radar Trailer

Radar trailer side view and front view

These mobile devices display the drivers travel speed on a large display along with the posted speed limit. Their goal is to encourage compliance.

Their effectiveness tends to be limited to the times when they are displayed - with minimal effect on speed when they are removed. A drop in speed of 25 percent is possible with the devices when displayed.

After a series of applications an overall drop in speed of about 6 percent has been found when traffic volumes are less than 600 vehicles per day. On higher volume streets their impact has been found to be negligible.

Speed Radar trailer

Temporary Installation

Permanent speed limit sign 3M

Permanent Installation


  • This tool can be effective when displayed and may improve effectiveness with multiple applications on lower volume streets (<600 vpd).
  • May be popular with residents.
  • Low cost measure.
  • Can be used with Speed Alert Program.
  • Easily deployed.


  • Minimal effectiveness when device is removed.
  • Minimal long-term impact on travel speeds.
  • Requires staff time to & from location to location.
  • Subject to vandalism.
Summary of Effectiveness
Volume Reduction No
Speed Reduction Yes
Safety Improvement Unknown
Streets to Use On Collector, Local Local/Collector
Use on Bus Route Yes
Use with Curbs and Gutters Yes
Spot or Area-wide Use Spot
Emergency Service Access Issues No
Impacts on Arterials Unlikely
Change in % Truck Unknown
Environmental Changes No
Dependence on enforcement No
Level of Violation Low
Aesthetics and Landscaping No