The Bergen County, N.J., Police Department converted one of its Ford Crown Victoria police cruisers into a propane-gasoline hybrid last summer in an effort to save money as gasoline prices soared. The conversion has reduced the fuel costs for the vehicle without any adverse effects on the vehicle's operation.

Because police cars are used for hours at a time and travel many miles daily, county fleet managers sought to find a fuel comparable to gasoline, which reached extraordinary costs this summer. They tested compressed natural gas (CNG), but found that the police cars could not operate as many hours on a tank of CNG as they could on regular gasoline, and it took a significant amount of time to refuel with CNG.

Next, fleet managers selected a vehicle to test a propane fuel system that would allow the operator to switch between gasoline and propane. Bergen County paid about $3,000 for the bi-fuel hybrid propane conversion, performed by Ken Smith Motors of Ridgewood, N.J. The conversion included the installation of a propane fuel injection system and a 26-gallon propane tank in the trunk. Drivers refuel the propane at a local station, Modern Propane, in Lodi, N.J. On average, the vehicle can travel approximately 300 miles on one tank of propane fuel.

The car has saved 20 to 25 percent in fuel costs, and the county is studying the exact emissions reductions and environmental benefits of using the fuel. Once fleet managers have conclusive results, they plan to convert another police cruiser to the bi-fuel system.

Project: Propane-powered police cruiser

Jurisdiction: Bergen County, N.J.

Agency: Police Department

Vendor: Ridgewood, N.J.-based Ken Smith Motors

Date completed: July 2008

Cost: $3,000