A motor vehicle blind-spot detection system has a remote sensor covering a rear-quadrant blind spot sensing zone and a forward-quadrant side impact sensing zone. A control module receives signals from a side impact sensor and the blind-spot detection sensor, calculates an approach vector of an object in the side impact sensing zone and/or the blind spot sensing zone, determines that the object will impact the vehicle, initializes a side impact algorithm controlling activation of an occupant safety device, detects an impact on the side of the vehicle and determines a magnitude of the impact, compares the magnitude of the impact with a threshold value established at least in part based upon the magnitude of the approach vector, and activates the occupant safety device if the magnitude of the impact exceeds the threshold value.