About 80 cyclists have been given £30 fines for jumping red traffic lights in Oxford in just two hours.
On Wednesday, Thames Valley Police carried out a crackdown on cyclists who ran red lights at the junction of Broad Street and Parks Road.
It followed complaints to police. An operation held five weeks ago saw 100 cyclists receive fines.
Pc Stephen Higa said most people admitted the offence. Police plan to repeat the spot-checks.
"About 90% of people realise what they have done and they accept what they have done," said Pc Higa.
"People we are catching live in Oxford and work in the city centre."