WASHINGTON, DC -- FedEx Express is putting 20 hybrid delivery trucks into operation over the next four to five months in an effort to simultaneously reduce vehicle pollution and boost fuel efficiency. At a press conference here in the nation's capital, FedEx Express president David Bronczek said the company's new OptiFleet E700 diesel-electric hybrid truck has 90% lower particulate emissions and 75% fewer smog emissions than its diesel-powered W700 vehicle, while gaining 50% better fuel economy. He said the company plans to monitor the operation of these pre-production hybrids through the end of this year. Based on how they hold up under continuous commercial operation, Bronczek said FedEx Express could begin replacing its delivery fleet of 30,000 trucks with hybrids as early as the fall of 2004. "These trucks have to endure all of the commercial aspects of our business," he said, noting that FedEx Express' fleet drives two million miles a day. "If they prove themselves, we could start designating hybrids as our replacement vehicle over the next 10 years for our U.S. and Canadian fleet." From an operations perspective, FedEx Express said there are few differences between the hybrid E700 and its W700 vehicle. With a Gross Vehicle Weight of 16,000 lbs, the E700 is about 100 lbs heavier than the company's current delivery trucks, said maintenance director Sid Gooch. "From a maintenance perspective, there's a few new components we have to monitor and our technicians will require some new training, but that's nothing new," he told Fleet Owner. "The encouraging thing with this hybrid vehicle is potential maintenance savings. Aside from the fuel economy improvements, the vehicle using 'regenerative braking' which reduces brake usage, potentially extending brake life and tire life as well." The E700 comes equipped with a four cylinder Mercedes Benz diesel engine and electric motor linked through an Eaton Fuller AutoShift medium-duty transmission A particulate trap is in place on the E700's engine to help reduce emissions, FedEx said. A hybrid drive unit developed by Eaton, equipped with an AutoClutch motor/generator, manages the switch from the diesel engine to the electric motor depending on the operational mode of the vehicle. Gooch said switching from the diesel to the electric drive system takes 12 seconds and notes that power steering is not available when the truck is in electric mode, a characteristic that could be changed on future models.