Diesel Hybrid Mass Transit If you live in a city like New York,
Chicago, or San Francisco Calif., and you use public
transportation, chances are good that you've already been a
passenger on a diesel hybrid bus. Nearly all buses and heavy-
duty large trucks use diesel engines because of the massive
torque available -- torque helps the vehicle pull huge amounts
of weight. Just like cars, they use either parallel or series
hybrid systems to assist the diesel engines in these buses. San
Francisco's hybrid bus system, first unveiled in April 2007,
uses a series hybrid system where the engine turns a generator
that produces electricity to power electric drive motors that
propel the bus. The wheels aren't turned by diesel power
directly, but rather electricity. Seattle Wash. King County
Metro Transit buses run on a parallel hybrid system - this means
that at low speed the bus is mostly electrically driven, while
at medium speeds it operates on a blend of diesel and electric
power and at high speeds it runs on mostly