Abstract
This article describes the use of machine vision technology to persuade motorists to adhere to a 50 mph limit through a motorway widening scheme. The layout and operation of the Speed Violation and Detection/Deterrent (SVDD) system developed by Travers Morgan, Computer Recognition Systems and NEI Control Systems is outlined. Covert monitoring of the 11 km stretch of the M20 in Kent between junctions 5 and 8 using SVDD revealed speed violations of up to 57% with speeds as high as 100 mph. The effect of linking a trailer mounted variable message sign to the system several months later was to reduce the 85 percentile speed from 62 mph to 51 mph. Even without the threat of prosecution SVDD changed driver behaviour.