Analysis of average delays of roundabout Vinkovacka - Drinska in Osijek

The intersection traffic analysis involved the assessment of capacity and adaptability of the observed traffic solution to the needs of different types of traffic and users. Indicators analyzed in the qualitative assessment are: capacity reserve, degree of saturation, delays and queue length at the intersection. Delays are an indicator that directly affects traffic users, considerably more than engineering-oriented capacity or capacity reserve. The same indicator was used to evaluate the level of service of the intersection. The microsimulation models are very useful tool for the analysis and prediction of traffic conditions on existing and planned intersections. However, it is questionable whether they can be expected to give realistic modeling results that can be applied in the methodology of analysis and design of roundabouts in local conditions. The VISSIM microsimulation traffic model used for traffic simulation and the traffic indicator which had been selected to analysis was the indicator of a delay. The best insight into the applicability of a VISSIM microsimulation traffic model on roundabouts in local traffic conditions is provided by the comparison of modelled and measured data. The process of model calibration and validation implements the comparison with values of traffic parameters measured in real traffic conditions. The selected traffic indicators for the calibration and validation procedure were travel time and queue. The analyses third traffic indicator of average delay at the observed roundabout was chosen to serve as an efficiency measure of the calibration. Measured delay was compared with modeled delay for the same traffic stream with calibrated and default values of input model parameters. Results of analysis and comparison measured and modeled data of average delays are given in this paper.