As early as next month, Peterbilt Motors Co will begin full production of two medium-duty hybrid vehicles. In addition, the OEM is also actively developing and testing technology for two heavy-duty hybrid configurations, one of which is tentatively slated for release later this year. Included are a hybrid electric vehicle for long-haul applications and a hydraulic hybrid model for vocational and stop-and-go operations such as refuse collection. Featuring the OEM's Hydraulic Launch Assist technology, the system recycles a truck's kinetics energy to conserve fuel and assist in acceleration. In this heavy-duty application, Peterbilt explains fuel efficiency and emissions reductions are achieved because the system's batteries power the heating, air conditioning and vehicle electrical systems while the engine is off.