Compressed natural gas adaptation kits were installed in 15 1980 and 1981 Chevrolet Malibus and two other vehicles. Dual fuel systems were used: all vehicles could convert back to regular fuel with the flip of a switch. Compressed natural gas was used becaused it costs less than gasoline, does not cause engine wear, is safe in accidents, and burns cleaner than gasoline. The evaluation of fuel costs covered a 3-month period. Some additional costs are anticipated for the training of mechanics in the operation and maintenance of the system. But the system has been ruled cost effective enough to warrant further conversions within the patrol car fleet. A table details vehicle and refueling costs.