X-Prize shows some 100-mpg cars can go the distance

The intensity of the competition for the $10 million, 100-mpg Automotive X Prize is getting in to high gear.

On Friday, all 12 teams, fielding 15 cars, took to the high-banked oval at Michigan International Speedway to prove they can go the distance in the range test. This test requires Mainstream contestants, essentially those with four seats, to go 200 miles without refueling. Alternative contestants, having two seats, only have to make the 100-mile mark. On Thursday, the teams competed in the mileage competition, when all the teams had to prove they could get 100 mpg.