Officers are appealing for witnesses after a road traffic collision on North Carr, Dalton.
The incident happened at 9.09 pm on Friday and involved an off road bike, a marked police vehicle (Vauxhall Astra) and a stationary Ford Focus.
The motorcyclist was riding along North Carr and was then in collision with the rear of the Ford Focus. The rider was left with a broken pelvis and wrist.
Police were following the motorcyclist at the time of the incident and so the matter has been referred to the Independent Police Complaints Commission which is standard procedure.
Any witnesses are asked to contact Sgt Richard Pell of the Roads Policing Unit on 101.