Abstract: A map matching method for a vehicle safety warning system (VSWS) is provided. The method includes the steps of a) determining if intelligent transportation system (ITS) map data is available, b) determining a vehicle location and a vehicle heading, c) determining an envelope area around a road feature defined by the ITS map data, d) determining a segment heading for a segment of the road feature, e) determining a separation distance between the vehicle location and the segment if the vehicle location is located within the envelope area, the segment heading is substantially similar to the vehicle heading, and optionally, the segment elevation is substantially similar to the vehicle elevation, and f) map matching the vehicle location to the segment if the separation distance is less than a threshold.

Abstract: An apparatus for sensing a vehicle crash condition includes an accelerometer (20) for sensing a vehicle crash condition and for providing a signal having a characteristic indicative of the vehicle crash condition. A crash velocity determining circuit (74) determines a crash velocity value (78) from the accelerometer. Crash metric determining circuits (80, 82, 94, 96, 104, 108) determine crash metric values functionally related to acceleration. Threshold determining circuits (88, 98, 112) determining associated threshold values functionally related to the determined crash velocity value (78). Comparators (90, 100, 116) compare the determined crash metric values against associated threshold values. A controller (34) provides a control signal to control actuation of a restraining device in response to the comparison. A shape monitoring circuit (120) determines if the shape of the acceleration signal matches a predetermined shape. If the shape matches, the controller provides the control signal.