Road signs which detect speeding drivers and flash warning messages to slow down are being used in south Wales for the first time.
The solar sign technology was developed in Wales
The solar-powered signs sense how fast motorists are travelling and warn drivers to reduce their speed.
Two signs are being used on the A48 in Newport and near a school in the Vale of Glamorgan.
SolarGen, the firm behind the signs say they do not record how fast the traffic travels unlike speed cameras.
The signs, known as Variable Messaging Signs (VMS), work by an internal camera assessing the speed of oncoming traffic and flashing up messages in English and Welsh warning the driver to slow down.
The signs are stand alone and don't need a mains power source because it runs on solar energy collected by panels connected to the unit.
Signs are already in place on Newport's A48 between Langstone and Chepstow and outside the village school in Pendoylan in the Vale of Glamorgan.
But the signs are expected to be erected in Carmarthenshire and in Monmouthshire soon.
Vivien Davies, who works at SolarGen Solutions based in Cwmbran said that the signs were proving very popular.
"Motorists seem to like them because although they warn the driver to slow down, you don't get caught speeding by the sign unlike a speed camera.
"And research by the Transport Research Laboratory shows that they are more effective in reducing the number of drivers exceeding the speed limit than imposing fines.
"They are very environmentally friendly because they are run on solar power and use the latest LED technology.
"And because they don't need to be connected to the mains, they are popular because you don't have to dig up the road to install them.
"I think these signs will play a big part in trying to get motorists to reduce their speed in the future," she added.
Both Newport and the Vale of Glamorgan councils have said that they hope the signs will be a cost effective way of reducing traffic speeds and accidents.