Significant fuel cost reductions are being achieved using Compressed Natural Gas (CNG) in lieu of gasoline as a vehicular fuel in Postal delivery vehicles. A total of 98 operational vehicles have been converted for dual fuel operation. In a twelve month period the vehicles traveled 446,815 miles on CNG vs. 109,649 miles on gasoline. CNG usage has increased from 29% in the first month of operation to 89% in the twelfth. Fuel costs were 9.9 cents per mile for CNG as compared to 14.9 cents per mile for gasoline.