Warning over 'flash for cash' scam
16 August 2013 Last updated at 07:59 BST
Drivers are being warned not to take the apparent generosity of other motorists for granted in a new take on the "crash for cash" insurance scam.
While the Highway Code states that headlights should only be flashed "to let other road users know that you are there", many use it as a way of inviting other road users to pull out.
In the "flash for cash" scam, a driver in an approaching car flashes their lights in this way, but then deliberately drives into the other vehicle.
Richard Westcott reports.