A spokesman for the CPS said: "After CPS West Midlands notified local police forces of this issue in early November, Warwickshire Police and West Midlands Police decided to stop prosecuting uncontested speeding cases involving variable speed limit signs
The regulations governing variable speed limit signs
are set out in the Traffic Signs Regulations and General Directions 2002.
It said the numbers displayed on some variable speed limit signs
on the M42 were too tall and too narrow to be visible to motorists.
Engineering Countermeasures for Reducing Speeds is a quick reference tool listing countermeasures, such as speed humps, traffic circles, in-roadway warning lights, and variable speed limit signs
, and their respective effectiveness in a tabular format.
The government body is to introduce jam-busting methods like variable speed limit signs
, better road-side driver information on one in three motorways by 2004 and automatic accident detection which will warn motorists against approaching snarl-ups.
The company is hoping to win European orders for its variable speed limit signs
- which are powered by way of a built-in solar panel.