A REVIEW OF THE PLAN TIMINGS FOR LEICESTERSHIRE COUNTY COUNCIL'S URBAN TRAFFIC CONTROL SYSTEM

Since the Leicestershire County Council urban traffic control system became established in 1975, a major development has been an 11 mile extension of the system to Loughborough. In the Loughborough system data for six outstations are concentrated on to one circuit between the control centre and a central point to minimise telephone circuits. Signals in the Leicester system, divided into 13 sub-areas, are on the same fixed cycle time plan which varies according to time of day. Based on traffic plans calculated in 1974 using TRANSYT each sub-area uses about seven plans during a working day reverting to vehicle-actuated working at night-time. With vehicle registrations increasing at 2% annually, a pilot study has been undertaken to assess the effect of new traffic plans based on up-to-date traffic data. Results of the re-timings are discussed, which showed a 22% decrease in AM peak journey times and 9% at PM peak times. The results of the pilot study were used to update the peak-hour plans in the other sub-areas using TRANSYT timings. It is shown how transyt can be used not only to produce optimised signal timings, but also to predict various flow parameters for a given set of signal settings. The review shows the value of updating urban traffic control systems to reflect current traffic patterns. (TRRL)