AMHERST, Mass. - Ever wish your car got better mileage? How about 612 miles per gallon? That’s exactly the mileage attained by a car designed by a group of six University of Massachusetts mechanical engineering students this past academic year. Led by professor Ian Grosse, the team took top honors at the National Supermileage Design Competition held in Marshall, Mich., May 30-31. The UMass vehicle placed first in the U.S. and third worldwide. This was the University’s third year in the international collegiate competition, which is sponsored by the Society of Automotive Engineering.