US Patent 7222004 Vehicular navigation with location-based noise reduction

A method or system for managing the noise level of a vehicle establishes one or more noise sensitive zones in a work area. A present location is determined for a corresponding vehicle in the work area. A charge level is measured. The charge level pertains charge level of an energy storage device of the vehicle. A mode of operation of the vehicle is selected based on the determined present location of the vehicle, the established noise sensitive zones, and the measured charge level. The mode of operation is selected from a quiet mode and a charging mode, or the equivalent of either.