Onboard Sensing System for Intersection Safety

A dedicated onboard sensor that used wireless communications devices was developed for collision avoidance around intersections. Four ZigBee wireless receivers were installed in the four corners of the driver's vehicle. Each receiver was shielded and had slight directivity. These settings enabled the sensor to estimate the positions of transmitters on pedestrians, bicycles, motorcycles, and vehicles on the basis of a comparison of four signal strengths received from the four receivers. Positions were obtained relative to the driver's vehicle as combinations of four directions: near or far and approaching or leaving. Because the estimation algorithm considered relative values obtained from the four wireless receivers, the detection results should not have been affected by the transmission power. Onboard sensors with vision, lidar, and radar cannot detect objects hidden by road facilities and other vehicles. Although infrastructure sensors for vehicle-to-infrastructure cooperative systems can detect such hidden objects, they are substantially more expensive than onboard sensors. The onboard wireless sensor developed in this work would function as an alternative tool for collision avoidance around intersections.