This paper describes the development of a technique for analysing complex traffic signal settings, designed to accommodate light rail crossings. The at-grade section of the north extension of a light rail line at Dallas, TX, USA, will be located between an expressway and a six-lane divided arterial road. It is envisaged that the roads crossing the motorway and arterial road will also cross the extension at-grade. The feasibility of these at-grade crossings was determined by analyses using: (1) TRANSYT-7F; (2) the Highway Capacity Manual Software; and (3) TRAF-NETSIM. The complex timing plans, developed for this system, involved three separate timing plans, which the controller could put into operation immediately on demand. The following modifications of TRAF-NETSIM were made, to allow the accurate simulation of this situation: (1) identical offsets and cycle lengths for all timing plans; (2) different first and last phases for each cycle; and (3) same first intervals and positive first interval green times for all periods. Some examples of average total delays and maximum queue lengths at intersections are tabulated. The resulting method is useful for analysing the effects of complex, frequently changing signal setting plans.
Abstract