The fleet manager for the Dunn Lumber Company in Seattle said the hybrid Kenworth Class 7 truck they just got has improved the company’s fuel economy by 35 percent.

The diesel-electric hybrid has a 240-horsepower Paccar engine that kicks in at speeds over 30 mph.

Under 30 mph, the truck uses a combination of diesel and electric power.

Kenworth is offering limited production of the hybrids to city fleets and utilities, and plans to go into full-scale production next year.