US Patent 8140219 Automatic glare reduction system for vehicles

An apparatus and method of controlling the transparency of at least one window in a vehicle includes at least one multi-segment light filtering element, each segment having a controllable light transmissive characteristic. The apparatus includes at least one sensor configured to determine the physical location and orientation of the vehicle, a memory that includes stored road map information including glare characteristics of each roadway, and a control unit electrically connected to the memory and at least one sensor. The apparatus and method is configured to automatically adjust the transmissive characteristic of the at least one light transmitting element based at least upon stored road map information and the location of the vehicle.