ATLANTA — The largest for-hire carrier in North America has announced it has ordered 50 new-generation hybrid electric delivery trucks and also would acquire 4,100 low-emission conventional vehicles during 2006.

UPS’ hybrid vehicles use regenerative braking

The hybrid electric vehicles (HEV) are being purchased in two sizes from International Truck and Engine and Freightliner LLC. They will feature lithium ion batteries that are capable of faster re-charging and have a longer life than batteries used in previous generations of HEV’s. The truck bodies will be identical externally to the signature Brown trucks that now comprise the UPS fleet.

The first of the 50 HEV’s will be deployed in Dallas and will join more than 10,000 low emission and alternative-fuel vehicles already in use in the U.S. and Canada. The UPS alternative fuel fleet currently includes trucks powered by compressed natural gas, liquefied natural gas, propane, electricity and hydrogen. Research also is underway with the Environmental Protection Agency on a hydraulic hybrid drivetrain, the company says.

A hybrid electric vehicle replaces a conventional engine and transmission with a small fuel-efficient diesel engine that acts as a generator to provide electrical energy for batteries and drive motors, which in turn assume the primary role of powering the vehicle. When additional power is required, the truck can draw it directly from the small engine.

The hybrid electric vehicles also use what is known as regenerative braking, meaning the energy generated when stopping the moving vehicle is captured and returned to the battery system as electrical energy.

“We’re excited to be among the first to deploy this latest in HEV technology because it promises a 35 percent increase in fuel economy in addition to a dramatic decrease in vehicle emissions,” said Robert Hall, UPS’s fleet environmental manager. “UPS has been involved in HEV research for more than eight years, but that’s just one part of a multifaceted strategy to reduce fuel dependency, cut greenhouse emissions and in the long run, reduce operating costs.”

The 4,100 low emission vehicles offer a 15 percent improvement in fuel economy over the vehicles that will be retired — saving roughly 1.5 million gallons of fuel over the course of a year, emitting 16,000 fewer tons of CO2, UPS says.

The majority of the 4,100 low-emission vehicle chassis to be purchased in 2006 will be made by Freightliner and will enter the UPS fleet throughout the year, allowing the retirement of older trucks.