In some cities, garbage trucks, with their rackety diesel engines, wake up the entire neighborhood. For the heavy-duty trucks in Volvo's FE Hybrid lineup, though, noise is not an issue, at least not at when moving slow enough. You see, the FE trucks are parallel hybrids and can operate at low speeds using just the electric motor and lithium-ion battery pack. The diesel engine is only called upon when the driver smashes the accelerator pedal or when the truck's battery pack runs out of juice.
Volvo Hybrid Truck