Vehicle activated signs

Vehicle Activated Signs (VAS), are roadside digital signs that use radar technology to display a message when they are approached by a driver exceeding the speed limit or going too fast for the type of road, especially when there is a hazard, e.g. a bend or a crossroads.

VAS are normally used to try to reduce a driver's speed by displaying the speed of the vehicle or a message e.g. 'Caution Bend' or 'Caution Too Fast - Slow Down'. They can also warn drivers of a safety camera if they are exceeding the speed limit. VAS do not record any data for prosecution purposes.

VAS can be moved from site-to-site and are used as an alternative to speed cameras or humps.

"Speed sensing signs" were first trialled on the A32 in Hampshire in September 1979, after a £5,000 investment. A second study was held on the A343.