Now hilarious videos from all over the country are being shared online showing lads running as fast as they can past radar speed signs.
The LED signs are intended to tell motorists how fast they're going so that they'll slow down if they're over the speed limit.
But now people are using the speed testing tech to race on foot against their mates, battling it out to see who can clock the highest speed.
Jack Nixon fired the starting gun on the craze when he uploaded a video of four of his mates pegging it down a street past a radar speed sign, with the fastest clocking in at 18mph.
Since posting the clip, which has now racked up over 60,000 likes, Jack's even directly challenged Usain Bolt by asking the champion sprinter: "fancy a go?"
But it seems that everybody wants to join the running battle by responding with videos of their own being measured by speed cameras.
Aaron Johnston shared a clip of him screaming encouragement as his mate sets a speed of 15mph.
And another more ambitious effort was shared with the caption "Tried to make the 30 speed limit sign light up".
It seems that the light-up speed signs don't always get it right though.
Adam Gardner's clip of a bloke slowly running past one says that he's going at 22mph.
The footspeed world record currently stands at 27.8mph and was set by Usain Bolt in a 100m race in Berlin in 2009.
Speed cameras normally work by measuring the average speed with which a number plate has travelled between two points.
But radar cameras work using the Doppler effect like a speed gun, so they'll measure something moving quickly near them even without a vehicle.
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