Cleaner tailpipe emissions from natural-gas vehicles can reduce smog-forming potential by up to 60 percent compared with gasoline.
The challenge now is to reduce or eliminate some of the drawbacks -- chief among them the shortage of natural-gas refueling stations.
In 1984, Ford produced 27 natural-gas Ranger pickups for evaluation.
In addition, the company is participating in an evaluation of 14 natural- gas medium-duty Ford trucks, as well as a natural-gas heavy-duty truck.
Next year, Ford plans to begin in-house production of a natural-gas full-size car.
A key goal of the new qualified vehicle modifier program has been to improve the quality of converted natural-gas vehicles in the marketplace.