PURPOSE: To obtain accumulated times on the operating path of a vehicle within a vehicle speed range and to grasp the congestion of traffic readily, by reading the stored accumulated times within the vechicle speed range by a reading machine outside the vehicle.

CONSTITUTION: A vehicle speed range judging circuit 12 jduges in what part of the five vehicle speed ranges, i.e. 0km/h, 0<v≤10km/h, 10km/h<V≤40km/h, 40km/h<V≤70km/h, and 70km/h<V, a vehicle speed signal V from a vehicle speed computing part 4 of a vehicle speed sensor 2 is locted. A vehicle speed accumulating circuit 13 accumulates times t11...t15 within said each vehicle speed range, and outputs the using rate of each vehicle speed range. A memory device 18 is formed so that it can be removed from the automobile and can be connected to a data printe outside the vehcle so that the memory of the device can be printed out. The device is connected to a computer outside the vehicle and the memory can be stored in the memory circuit of the computer.