Analytical investigation on the minimum traffic delay at a two-phase   intersection considering the dynamical evolution process of queues
  This paper has studied the minimum traffic delay at a two-phase intersection, taking into account the dynamical evolution process of queues. The feature of delay function has been studied, which indicates that the minimum traffic delay must be achieved when equality holds in at least one of the two constraints. We have derived the minimum delay as well as the corresponding traffic signal period, which shows that two situations are classified. Under certain circumstance, extra green time is needed for one phase while otherwise no extra green time should be assigned in both phases. Our work indicates that although the clearing policies were shown in many experiments to be optimal at isolated intersections, it is sometimes not the case. 
Hong-Ze Zhang, Rui Jiang, Mao-Bin Hu, Bin Jia
physics.soc-ph nlin.AO