ROAD CONDITION MONITORING DEVICE

PROBLEM TO BE SOLVED: To instantaneously report the occurrence of car accident to a police and a firehouse and to prevent the occurrence of secondary disaster by simultaneously issuing an alarm to a following vehicle by providing a reflector for reflecting sonic waves and a controller for receiving the reflected sonic waves, recording these sonic waves and reporting them to a traffic control center or the like. SOLUTION: Frequencies f1 and f2 different a little are generated by a controller 2 installed above a road, and sent into air after performing electric/ acoustic transduction through a parametric transmitter/receiver 1. On the assumption that a vehicle 4b collides with a vehicle 4a while this differential frequency f1-f2 is reflected by a reflector 3 and reciprocated through a propagation path 5, a non-linear acoustic wave 6 caused by an abnormal sound f3 generated at such a time is propagated in air, the sonic wave with differential frequency f1-f2 propagated through the propagation path 5 is interferred and modulated, and this sonic wave is turned to a reflected sonic wave and received by the parametric transmitter/receiver 1. Then, the generation of abnormality is detected by a controller 2, recorded and speedily and automatically reported to emergency contact facilities 7a and 7b at the same time.