The major cities of many developing countries are beginning to experience high levels of congestion due to an extremely rapid rise in car ownership levels. There is scope for relieving this congestion through the use of advanced Area Traffic Control techniques like TRANSYT, a well known British program to design fixed-time coordinated signal plans. This research investigated the value of such an application testing the performance of TRANSYT plans at a corridor in Santiago de Chile. Standard fixed-time plans were produced with TRANSYT and implemented on the corridor. Their performance was assessed through extensive data collection using an instrumented car and portable computers. It was found that the implementation of TRANSYT plans produced improvements in journey time and stops similar to those encountered elsewhere in the developed world. However, the special traffic behaviour of buses in the corridor was not well modelled by standard methods in TRANSYT. Further research identified the need for a more detailed link structure in the network, a redefinition of some basic measures like saturation flow and cruise times and a re-calibration of the platoon dispersion parameters in TRANSYT. This additional effort produced considerable improvements in performance, more than doubling the benefits of plans prepared with more conventional TRANSYT values. Further analysis showed that the benefits from this effort covered investment and research costs in less than a year.
Abstract