ROAD CONDITION MONITORING DEVICE

PROBLEM TO BE SOLVED: To simultaneously monitor plural monitor object areas such as plural lanes or road surfaces through one device without being affected by time or weather and to display a caution or road conditions for a monitoring person or a passing vehicle by using the Doppler signal component or background echo sound of acoustic signal. SOLUTION: A signal processor 14 detects the speed of a vehicle and the traffic volume of vehicles by detecting the Doppler signal component. Besides, the presence/absence of obstacle is detected by detecting any signal component except Doppler signals. Further, the condition on the surface of road is detected by detecting the probability distribution of sound pressure values in the background echo sound. Then, the detected information is communicated to a central monitoring device 11. The central monitoring device 11 monitors the information from the signal processors 14 in respective blocks for each block and concerning the presence of obstacle on L1 and the generation of traffic jam on congested block L2, the alarm is issued by an alarm device 15 for the congested block L2 and a block L3 usually traveling vehicles and displayed on a display device 34.