Calibration of an acceleration detector is initiated by a user depressable button such as a button indicating a vehicle is at rest and/or by the detector reading an OBDII vehicle communication protocol to determine the condition of the vehicle. Calibration permits more accurate measurements in a vehicle...http://www.google.de/patents/US7397416?utm_source=gb-gplus-sharePatent US7397416 - Police radar/laser detector with integral vehicle parameter display using a vehicle interface
