How many wheels does a car have? Four, according to the U.S. Congress. Or three. Three-wheeled vehicles can qualify, too.

Automotive News explains, "A bill to make fuel-efficient three-wheeled vehicles eligible for federal funding now available to automakers and their suppliers has passed Congress and is headed to the White House for President Barack Obama's signature." The bill will provide Energy Department funds to startups like Aptera Motors and Elio Motors, which have developed experimental three-wheeled vehicles that reportedly get significantly better fuel economy than most of today's passenger cars. In some cases, the vehicles are electric.

Autoblog adds, "three-wheeled vehicle platforms sometimes have the potential to use less energy to operate than their four-wheeled siblings, though some still question the inherent safety of such designs. Assuming the bill passes the President's desk, any manufacturer of enclosed three-wheeled vehicles that can carry at least two adults while returning at least 75 miles per gallon will be eligible for funding, though the DOE will still approve applications on a case-by-case basis."

It will still be a while before you see a three-wheeled car in the neighbor's driveway. Automotive News reports, "Aptera plans to begin mass production of its plug-in electric vehicle, called 2e, in the middle of next year." The company has not explained how it will sell the cars, however, and has no dealerships in place. "CEO Paul Wilbur has said the company wants to borrow $75 million from the Energy Department" to help begin the manufacturing process and develop a distribution network.

If you're in the market for a new car, check out the U.S. News rankings of this year's best cars as well as this month's best car deals.