In the world of higher education, summer is usually the off-season. But for some students, this summer was the culmination of years of hard work in a 2,400-mile solar car race from Plano, Texas to Calgary, Alberta. Fifteen teams of students drove photovoltaic-powered cars across the North American Solar Challenge finish line in Calgary Tuesday, led by the University of Michigan Solar Car Team and its vehicle, Continuum. Michigan's victory, which took about 51 hours and 42 minutes on the road, is its fifth NASC championship. The school also won the last NASC, in 2005. Jeff Ferman, the race manager for Michigan, talked about how rewarding it was to enter Calgary and be greeted by 40,000 people.The streets were lined with people," he said. "There were people on overpasses with tripods taking pictures." The Michigan team led almost the entire race from Texas, trailing only on the first day of driving when it had to stop to fix a minor electrical problem. But that 20-minute stop was the only time it had to pull over to make repairs, which team members said was one reason they did so well.