Of all the alternative fuels available, propane offers the best mix of vehicle driving range, durability, and performance. Many fleets have reported 2 to 3 years longer service life and extended intervals between required maintenance. Spark plugs from a propane vehicle last from 80,000 to 100,000 miles and propane engines can last 2 to 3 times longer than gasoline or diesel engines. Propane vehicles have the longest driving range of all clean-burning fuels.* What about performance? With propane, you don't have to sacrifice performance for environmental friendliness. With a propane-powered vehicle, power, acceleration, payload, and cruise speed are comparable to those obtained with an equivalent internal-combustion engine. Source: National Propane Gas Association/Propane Education & Research Council, February, 2000. PROPANE EDUCATION & RESEARCH COUNCIL