Vehicle-activated signs have been successful in reducing speeding in South Gloucestershire. At the end of March 2008, there were 96 such signs, reducing average speeds by four miles per hour.
What the signs do
The signs record the speed of a vehicle. If it is travelling above the speed limit, it flashes the speed limit to the driver.
Do they work?
We collected data before and after signs were installed.
This shows that:
- The percentage of vehicles travelling above the speed limit is down by 21 per cent
- 85th percentile traffic speeds are down by four miles per hour (the 85th percentile speed is the speed at or below which 85 per cent of motorists drive on a given road)
- Average traffic speeds have been reduced by four miles per hour
You can download the full report for more details by clicking the link in the 'Read more' box on the right-hand side of this page.
Vehicle-activated signs continue to be effective years after they are installed. We have produced two graphs that show this, which you can also download.