CAMBRIDGE, Mass. (AP) _ A vision of the future arrived Sunday, when tiny solar-powered cars in the American Tour de Sol came tooling over the finish line at Massachusetts Institute of Technology.

While the Indianapolis 500 was making its perennial display of the speed and power of the internal combustion engine, the four-day Tour de Sol was quietly making another point - not about who could finish first, but about a new technology that its pioneers expect to become commmonplace.

''What this race is really about is ... developing the (solar) commuter car,'' said Nancy Hazard of the Northeast Solar Energy Association, which sponsored the event. Based in Brattleboro, Vt., the 15-year-old, non-profit organization promotes the development and use of solar power.

The 208-mile Tour de Sol began Thursday in Montpelier, Vt., wending its way for a couple of hours each morning through the back roads of New Hampshire and Massachusetts.

While there are similar solar races run in Australia and in this country, Sunday's race was modeled on the Swiss Tour de Sol. That annual event, first held in 1985, draws competitors from all over the world and aims to establish the use of solar power for commuter cars that can travel up to about 50 miles a day, Hazard said.

The six entrants in the American Tour de Sol were teams from Alabama, MIT, New Hampshire Technical Institute in Concord, Dartmouth College in Hanover, N.H., and Worcester Polytechnic Institute.

Two cars were in the commuter class and resembled truncated sedans. The others were racers: low to the ground, their bodies narrow like a cocoon and topped with flat solar-panel roofs.

All were equipped with panels of photovoltaic cells that convert sunlight into electricity to run electric motors and charge their batteries.

Participation was uneven. There were breakdowns and false starts. One car competed only on Sunday. Another was on the road each of the four days but was dragged part of the way on a trailer because it lacked enough electric storage. Another needed charging by conventional electricity overnight.

But it didn't really matter, organizers said, because the purpose was to demonstrate efficiency and reliability of a developing technology.

The first finisher Sunday was Ed Passerini, a 51-year-old professor of environmental studies and humanities at the University of Alabama in Tuscaloosa, but the final winner would be calculated based on performance over the four days and other factors.

''This feels absolutely terrific,'' Passerini cried a few minutes after his vehicle rolled in on a grass patch to a silent and smooth finish at 10:50 a.m. About 50 spectators were there to greet him.

''The Indy 500 is a relic of the past,'' Passerini crowed. ''In the Year 2000 and beyond, this is the sort of thing we're going to be driving.''

Passerini said his three-wheeled car cost $2,800 and took three weeks to build. It clocked up to 45 mph on the straightaways, 13 mph on the hills and could travel 30 miles per day on solar power.

The car weighed about 800 pounds and was cobbled together from a trailer hitch and a two-seat yellow paddle boat fitted with a steering wheel and brake pedals. Solar panels covered the rear of the vehicle and four conventional car batteries soaked up the electricity.

Hazard said race rankings would be calculated based on road time and the degree to which the contestants relied on solar energy. But organizers stressed that winning or losing was beside the point.

''It's a vision of future transportation and a vision of the future,'' said Rob Wells, the race director and a Dartmouth researcher. ''It's also a wonderful opportunity for an educational experience.''