ElectraDrive is commercializing an Add-On Electric Drive (AOED) and related technologies to give trucks and other utility vehicles a plug-in electric capability without compromising the factory powertrain. The AOED allows a truck to run from grid electricity in the urban cycle, saving fuel, extending the life of the factory powertrain, and improving urban air quality. The factory powertrain remains available for highway driving and as a backup to the AOED. The AOED is modular and adaptable to most types of fleet truck.