A masked man is believed to have vandalised two speed cameras in Northampton early on Tuesday morning.
The lenses and posts of both cameras, on Barrack Road near to the site of the old Post Office, were sprayed with orange paint.
A Northamptonshire Police spokesman said they believed the masked man stood on a chair to paint the cameras just before 0630 GMT.
Anyone who witnessed the incidents are asked to get in touch with police.