Motorists are testing new 'social' ways to alert one another to speed cameras - with their mobile phones.
Software running on the phones uses the built-in GPS found on newer mobiles to warn drivers of nearby speed traps, whose locations have been pinpointed by other users of the system.
One free service, Trapster, was launched earlier this year. It runs on a range of phones, and claims more than 200,000 users, who have reported a global map of more than 115,000 cameras.
And since last week, users of Apple's iPhone have been able to download Nmobile, a similar application that costs around £3.
Nmobile founder Shannon Atkinson has said that police are positive about his service.
"If the application gets people to slow down, I think it's generally considered to be a good thing," he said in the New York Times.
Web-based technologies and GPS mean that there is now competition between camera-alert systems that rely on user-generated content.
Another UK-based dashboard speed camera gadget, the Mini Coyote, goes on sale this month for just under £200.
