Piotr Chmielewski alerted traffic police after setting off a speed camera in Bialy Bor, northern Poland, exceeding the 30mph speed limit while cycling.
According to Orange News, traffic police found Chmielewski in a state of undress when they caught up with him.
It was then that they noticed Chmielewski was completely naked apart from his underwear, which he was wearing on his head. He had been fully clothed when he set off the speed camera.
Police spokesman Waldemar Lada confirmed that two fines totalling around £200 ($321) had been subsequently been issued for the incident: one for speeding, and one for indecent exposure.
Chmielewski had unsuccessfully argued that at the time of arrest that he had in fact been wearing a thong.