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.
1. This tool can be effective when displayed and may improve effectiveness with multiple applications on lower volume streets (<600 vpd).
2. May be popular with residents.
3. Low cost measure.
4. Can be used with Speed Alert Program.
5. Easily deployed.
1. Minimal effectiveness when device is removed.
2. Minimal long-term impact on travel speeds.
3. Requires staff time to & from location to location.
4. Subject to vandalism.