BARSTOW, Calif. — The leaders in the solar-powered car race from Chicago to Southern California encountered 38-degree desert weather Monday as they neared the end of a 3,860-kilometre route using portions of old U.S. 66.

The American Solar Challenge that began July 12 in Chicago is to end Wednesday at Claremont, Calif., after passing through communities linked in the old Route 66 song: Kingman in northwest Arizona; Barstow in California's Mojave Desert; and San Bernardino just prior to the finish.

The leading car from the University of Missouri-Rolla has averaged about 68 kilometres per hour, moving at almost exactly the same pace Sunday to cover the 615 kilometres from Albuquerque, N.M., to Flagstaff in nine hours, said John Horst, a U.S. Department of Energy representative traveling with the racers.

The cars race each day from 8 a.m. until they halt at 6 p.m. wherever they are on the route. The 10 cars which made it to Flagstaff by Sunday evening were expected to approach Barstow along Interstate 40 before Monday evening's halt.

Most of the 20 cars remaining in the race are expected to reach Barstow on Tuesday before the survivors take part in Wednesday's final stretch.

As the leading teams approached Barstow late Monday, Missouri-Rolla had an elapsed time of more than 44 hours, 16 minutes for 3,080 kilometres. The University of Minnesota entrant was second at 48 hours, 37 minutes. The University of Waterloo, Ont., was third at 50 hours, 24 minutes, and the University of Missouri, Columbia was fourth at 50 hours, 26 minutes.

Most cars carry only the driver. A two-passenger entry from Queen's University, Kingston, Ont. was eighth in 52 hours, 14 minutes. Stanford students have the only other two-passenger design and were in 16th place at 74 hours, 32 minutes.