Comparing methods to optimise vehicle actuated signal control

Local vehicle actuated control is the most common form of traffic signal control in the Netherlands. An important parameter is the maximum green time. Currently, these parameters are fixed or are specified in a number of sets. In changing traffic conditions it is possible that the set of maximum green times is not fit to cope with these changing conditions. Therefore, methods were developed to deal with this problem and to change these parameters continuously. One of these methods is adaptive control, based on Webster´s formulas. Implemented in a real-life intersection it appeared that improvements of 3% to 20% in vehicle delay are possible, compared with normal vehicle actuated control. The simulations support these findings. Moreover, a method to adapt the maximum green times based on evolutionary algorithms is also able to improve the total delay, even more than adaptive control