Plain-clothes officers on bicycles are carrying cameras to catch unsuspecting motorists who drive dangerously.
Police are using the devices mounted on their bikes to target “blackspots” for bad driving.
Footage is uploaded to a secure site. There, it is checked to see if the driving warrants a prosecution or a “warning” letter to the motorist.
Road safety officer Damien Devanny, of Avon and Somerset Police, said the scheme aimed to “sow the seeds” of doubt in drivers’ minds so they take greater care when overtaking cyclists.
He said: “It could be a police officer, it might not be. Or it might be a member of the public with a camera. We are open and transparent about it, and share on social media, so we can change behaviour.
“Although they are in plain clothes, it’s like any member of the public doing the same thing.”
The cameras cost £500 and can film ahead and behind the bikes. Research by Bath University, in Somerset, suggests motorists are more likely to give a wide berth to cyclists in jackets marked “Police”.
A third of road traffic collisions involve a cyclist or motorcyclist.
Three quarters of the 43 police forces in England and Wales use a national database for footage from dashcams, head cams and mobiles.
The number of incidents reported to the “national dash cam safety portal” rose from 5,000 to 10,000 in the past year. Police prosecuted or took other action in 52% of cases.
Civil liberty campaigners say it raises privacy concerns.
