Japan employs left-hand traffic as in UK, while the USA and many other countries employ right-hand traffic. As a result, control of traffic lights on right-turn lanes is as important as signal control algorithm determining such parameters as cycle length, split, and offset. Mismanagement of right-turn vehicles will aggravate traffic congestion. In Japan, a right-turn vehicle actuation method is successfully implemented as a part of MODERATO, Management by Origin-DEstination Related Adaptation for Traffic Optimization. In the conventional method, appropriate green time is calculated based on right-turn demand detected with a spot sensor. However, traffic information under a spot sensor, whether or not a vehicle exists, may not be sufficient to derive appropriate green time depending on traffic demand. In consideration of this, a research group led by the UTMS, Universal Traffic Management Society of Japan, developed an image detector, which was able to detect vehicle presence in a designated area, and a right-turn vehicle actuation method that used the detector ("last year's method"). A field experiment confirmed that this method smoothed traffic and solved the problem of the current spot-sensor-based right-turn vehicle actuation method ("conventional method"), as presented at the World Congress last year. Based on last year's method, the authors have further developed a control method that skips yellow light if no vehicles are likely to pass the stop line if it comes on after a green right-turn arrow signal, to enable even smoother traffic. To confirm the effects of this new control system, the authors performed a field experiment, collecting and analyzing data for evaluation of smooth traffic and right-turn traffic behavior.
Samenvatting