A study on the policy switching control programs of pre-timed signal coordination

It is the prupose of this paper to optimize the policy switching control programs of pre-timed signal coordination under the condition that traffic demand changes with time of dav. For that purpose, firstly common cycle lengths corresponding to several demand levels are obtained through the methods such as theoretical calculation, approximate equation and GA approach. In GA approach, cycle length and offsets are optimized simultaneously. It is supposed that splits are given. Next, using several control programs consisted of cycle length, offsets and splits, the switching policy is optimized by DP.Total delay is employed as a criterion, which is evaluated by simulation. Switching offsets is perfomed over several cycles, and additional delay caused by traffic flow disturbance during the switching is considered. From some calculations, it was found that the desirable number of switching exists.

common cycle length

offset

optimization

DP

total delay