An Optimization of a Signal Control Scheme for Close Stagger Intersections based on Evaluations of Efficiency and Safety

In urban road systems,vehicles from different directions interfere greatly with each other in weaving sec-tions between two close stagger intersections.Especially,drivers′continuous lane change operations within limited wea-ving length have negatively influences on traffic efficiency and safety.Therefore,a coordinated signal control scheme for safety is developed based on comprehensive consideration of efficiency and safety.A signal light for right-turning vehicles is set up in a minor road of an upstream intersection to separate the conflicts from space-time,and systematically optimi-zing phrases and timing for close stagger intersections,in order to reduce vehicle delays and improve safety level.Then, intersections of Pushang Road-Jinzhou South Road-Jingang Road in Fuzhou are taken as a case study.Using Vissim and SSAM,the proposed scheme is compared with the current scheme,and another isolated optimization scheme in the re-spect of efficiency and safety.The results show that compared with current scheme,the efficiency and safety level of the isolated optimization scheme and the proposed scheme improved by 36.17% and 57.17%,respectively,w hich verifies the superiority of the proposed scheme.In addition,by adjusting distance between two intersections in Vissim,a similar com-parison has been developed,and the results show that the shorter of the distance of close stagger intersections is,the big-ger of the superiority of the proposed scheme.