Houston-based Waste Management, North America's largest waste management company, is field-testing the first prototype parallel hydraulic hybrid truck to be deployed in a waste collection vehicle.

Four parallel hydraulic hybrid-diesel collection trucks have been incorporated into Waste Management's fleet and are being tested in Fort Worth to study and optimize the hybrid system's efficiency and reliability. This system is the first among many technologies Waste Management expects to test and implement over the coming years.

Hybrid vehicles hold great promise for the waste industry because collection vehicles have many cycles of braking and acceleration along a given route. The four Peterbilt 320 vehicles in Fort Worth use a Hydraulic Launch Assist system, developed by Eaton, to capture and store energy during braking, which not only improves efficiency but reduces wear on brake pads. The stored energy is then transferred to accelerate the vehicle to the next pickup location, reducing fuel consumption and wear on the engine.

Though hybrid technologies have been successfully deployed in automobiles and light trucks, Class 8 vocational vehicles pose additional challenges to hybrid engine design. Among the largest vehicles on the road, Class 8 vehicles require a robust drivetrain that can handle heavy loads, and waste trucks have multiple systems - for compaction and lifting - that draw power from the engine, complicating hybrid design.

"We are working closely with a number of manufacturers to develop and test both hydraulic and electric hybrid systems for our fleet vehicles," said Eric Woods, vice president of Fleet and Logistics for Waste Management. "The challenge for our engineering team is to make our vehicles as efficient as possible while also ensuring they are tough enough to withstand wear and tear on the road. Though development is in early stages, we are optimistic that the investment we are making now will lead to a reduction in greenhouse gases and ultimately benefit both manufacturers and users of heavy vocational vehicles."

Waste Management operates one the largest commercial fleets. With annual fleet expenditures of up to $500 million, the company is in a unique position to spur innovation and efficiency.

This project is part of Waste Management's sustainability initiative announced last year. The company has a goal to increase the fuel efficiency of its fleet by 15 percent and reduce fleet emissions by 15 percent by 2020. Waste Management has been a pioneer in the waste industry in the use of LNG and CNG as an alternative fuel for its fleet and evaluating a wide range of technologies that could create fuel for vehicles from landfill gas, such as liquefied natural gas and synthetic diesel.