You tree-huggers will hate to love this: Heavy-Duty truck manufacturers Peterbilt and Kenworth are both offering two pretty cool mild-hybrid for its Class 6 and 7 trucks, commonly used for short-haul and in-town service.

The “highway” model uses an Eaton transmission system that stores braking energy in a LI battery pack, and drives an electric motor for either electric-only launch from standstill, or in combination with the diesel engine to reduce over-the-road demand on the engine, which spec’d much smaller than a standard model.

Pete and Ken trucks assigned to in-town, stop-and-go applications, like refuse and delivery service, incorporate a trick hydraulic launch assist system that accumulates pressurized brake fluid to be released through a turbine with enough gumption to launch the truck from a standstill without the engine. The ready-for service hybrid trucks have demonstrated 28 % reductions in both fuel consumption and emissions, not to mention a 50% reduction in brake wear.