New traffic entropy functions to quantify spatial traffic flow conditions and intelligent control logic of isolated signals

The authors propose new traffic functions to estimate space-mean-speed and traffic volume a few seconds ahead. They are based on the entropy parameter and traffic density which are obtained in the processing of a traffic flow image taken by a TV camera. The space-mean-speed and traffic volume estimated by the functions the authors proposed are very close to those of the actual traffic flows; the correlation coefficient between them showed more than 0.9. They have developed a control logic of isolated signals to change the signal timely, for which the information is given by the function they proposed. The effectiveness of the proposed logic has been examined by a theoretical approach and simulation analysis. The authors conclude that the proposed logic is more efficient than that of the time-gap-seeking as the traffic volume increases and the average cycle length approximates to the minimum