An electric motor and battery system is paired with an internal combustion engine on oil-electric hybrid trucks. The engine may be aided in acceleration by the electric motor, which in turn improves fuel efficiency. The energy yielding change in motion the electric motor uses is referred to as regenerative braking, as it generates electricity while braking. The hybrid system is able to run exclusively on electric power during idle and slow-moving traffic, which reduces fuel consumption and emissions. This type of truck combines the range of traditional diesel powered vehicles with the environmentally-friendly features and energy-saving efficiency of an electric vehicle