The city, under a 1991 law, is also stepping up its purchase of alternative-fuel vehicles.

The growing issue of air pollution may produce regulations that help alternative-fuel vehicles.

Increasing tax incentives for the production and purchase of alternative-fuel vehicles would also help.

Is there an alternative way to gas up these alternative-fuel vehicles?

"The hybrid is the most popular, but I wouldn't be surprised if in 10 to 15 years we see all types of alternative-fuel vehicles."

Yet Ford had combined sales of just 8,461 alternative-fuel vehicles across five model lines last year.

They have also provided consumer incentives to use alternative-fuel vehicles.

But it was not just a need to save money on gas that prompted him to buy an alternative-fuel vehicle.

The bill would phase in the expanded use of alternative-fuel vehicles during a three-year period.

Until then, 10 to 25 percent of the acquisitions will be alternative-fuel vehicles.