Wrightspeed, a California-based startup, has introduced the Route, an aftermarket hybrid-electric powertrain designed specially for use in medium-duty commercial fleet vehicles.

The company, which secured private investment capital in late 2010, says the Route features an on-board generator that charges the vehicle's battery while on the road. "Unlike in a conventional hybrid, the efficient electric motors are always producing the variable torque necessary to turn the wheels. This frees the generator from having to perform over the entire speed-load map, and allows it to operate at its most efficient point to charge the small, high-power battery," Wrightspeed explains in a press release.

"For electric drive to make economic sense, you have to displace enough fuel to pay for the technology," says company founder and CEO, Ian Wright. "That pretty much rules out passenger cars, because they don't burn enough fuel. Medium-duty trucks on commercial routes burn thousands of gallons of fuel annually."

Wrightspeed officially debuted the new technology last week during the ACT Expo in Long Beach, Calif. The company had retrofitted an Isuzu NPR with Route and says the vehicle's fuel economy improved from 12 mpg to 44 mpg on a cost-equivalent basis.