"The system cannot differentiate between a driver and the passengers on a bus, for example, but this goes some way towards remotely warning drivers that they can be detected using their phone".
The system will initially be used at sites in Attleborough, Holt, Norwich and Toftwood. This shows an illuminated mobile phone icon within a bright red circle and diagonal red line.
The Council's Road Safety Team and local company Westcotec have worked together to develop and deploy the system.
Chris Spinks, from the company's sales team and a former head of roads policing in the region, told The Times that the system was designed to "educate and inform the driver" - Westcotec has no plans to create tech for use in prosecutions.
"We are delighted to have been able to partner with Westcotec to trial this new technology across Norfolk".
DRIVERS using their mobile phones at the wheel are to be shamed by a new roadside detection system.
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The signs can can detect when signals are being transmitted by a handset inside a auto.
Although the signs are unable to log offending number plates, such a feature is being considered for development in the future.
Iain Temperton, team manager for road safety at the county council, described the technology as "cutting-edge" and said it would be used an "educational tool" throughout Norfolk to tackle the problem.
The road signs work by using a scanner to detect the radio signals emitted when someone in the vehicle is connected to a call, with this data used to illuminate a sign further down the road.
Norfolk roads policing Inspector Jonathan Chapman said the scheme is "welcomed".
If the signal detected indicates that a mobile phone is being used inside a vehicle, a road sign with a flashing visual message is activated as the vehicle passes to prompt drivers to stop using their phones. "Using a mobile phone at the wheel is one of the fatal four road offenses which can have devastating consequences if it causes a fatal or serious collision", Insp.