Improving the Performance of a Network of Signalized Roundabouts via Microscopic Traffic Simulation Tool

Abstract

Roundabouts are effective intersection designs which are rapidly gaining attention and popularity among traffic engineers. This is due to the roundabout's capacity to handle the mobility of a substantial number of vehicles. The ever increasing demand for more traffic capacity can be satisfied by either significant capital investment in infrastructure or creating more capacity by intelligent signalization. The appropriate traffic signal timing is critical in smoothing traffic flow. Inappropriate traffic signal timing not only causes delays and inconvenience to drivers but also increases environmental pollution. Thus it is important to investigate different signal timings to ensure that implemented plan will have a positive impact on the network's performance. The optimization of roundabouts' signal timing is relatively a new area of research. The problem is difficult to model realistically and computationally challenging. Due to the flow nature of the traffic problem wider areas of traffic must be regulated simultaneously in a network. This can be achieved via either field-testing or using a reliable simulation tool. Microscopic simulation allows a safer and cheaper evaluation of many more alternative signal timings compared to field-testing. Although development calibration and validation of simulation models for traffic networks are challenging. We present a model to evaluate the performance of a network of signalized roundabouts with which the combination of different traffic volume and cycle length scenarios can be intelligently studied. We also provide information on the development calibration and validation of the model as well as a real-life implementation on a network of roundabouts in Izmir/Turkey.