Hypermilers trade speed for savings, improve fuel efficiency

As the black mailbox draws closer, Larry Trowbridge?s gaze flicks from it to the digital speed readout in front of him. The numbers climb agonizingly slowly. 20...25...28... Then, suddenly, his hand taps the stubby gearshift of his 2007 Toyota Prius into neutral. The car begins to coast, the numbers start to drop again, and Trowbridge smiles the smile of a man who can eke 100 miles or more from a single gallon of gas.