Leicestershire Police officers are being encouraged use public transport or cycles while on the beat as part of a savings drive.
The force needs to save a total of £15m by March 2011. It has now reduced its fleet of vehicles from 483 to 443.
A police spokeswoman said selling the vehicles had already saved £52,000 and would save £155,000 in revenue costs.
She said officers were being encouraged to use cheaper transport only in non-emergency situations.
Supt Chris Haward said: "Leicestershire Constabulary is facing a period of extreme financial pressure, unprecedented in recent times.
"It is therefore vital that the force considers every opportunity to make cost effective use of its resources and continue to deliver an effective service across Leicester, Leicestershire and Rutland."
He said the force had used GPS mapping equipment to work out how often all of its vehicles were being used before deciding which ones to cut.
The force said officers using buses would act as a reassuring presence for passengers and those on bicycles would have more time to chat to residents and get to know the community better.