They look like normal...

They look like normal arrow signs, but if a car approaches a tight corner too fast, they light up and pulsate in sequence.

Eight of the radar-operated devices have been installed on the A6006 near Shoby, Leics - a prime accident blackspot. "Most motorists will be unaware of the new technology as it targets only those driving at inappropriate speed," said Tim Jarvis of Norfolk-based maker Westcotec.