Abstract: A method for predicting a traffic flow rate at a point on a road to control a traffic light signaling system measures a traffic density on the road to predict a traffic flow rate by utilizing the fact that a velocity of a vehicle on the road is restricted by an interval between successive vehicles, since the traffic density is locally increased when the vehicle interval is not uniform and therefore the spatial mean speed is lowered. This method offers higher accuracy by utilizing a correction coefficient obtained from an actual vehicle distribution, for instance, a coefficient derived from entropy.

Abstract: A beam of diverging electromagnetic radiation of a predetermined frequency is transmitted to a target and the doppler shift of frequency of an echo due to relative movement of the target and a point of reception is detected conventionally by combining the frequency of the echo and the predetermined frequency. The number of cycles within the detected doppler shift frequency is counted to provide a delay to initiate measurement of doppler shift at a preselected angle of incidence of the echo. The effective area of measurement is thus restricted to a narrow region of the beam with the resultant high degree of precision.