Calibration and Validation of VISSIM Parameters in Mixed Traffic

Abstract

AbstractMerging sections constitute a large amount of uncontrolled conflict areas, thus affecting overall performance of urban arterials and highways. There has been no study of merging behavior in a mixed traffic scenario, which significantly differs from conventional streams due to heterogeneous traffic with weak lane discipline. Simulation models need thorough calibration of its parameters and need to be validated for their versatility. This paper describes calibration and validation of VISSIM parameters for mixed conditions in a merging scenario. Further, it estimates capacity of highways at merging locations and capacity drop due to ramp traffic. Speed flow, speed distribution and other vehicular properties from a merging section on an urban arterial road in India are used to calibrate a VISSIM merging section. The calibration process is conducted using genetic algorithm by using an external MATLAB code and COM interface of VISSIM. The sensitive parameters of car-following and merging at conflict areas are calculated. Further, this model is effectively validated for another traffic section located on the same arterial road. Traffic stream with various flow levels are generated to obtain capacity with and without ramp traffic. A capacity drop is observed as compared with a mid-block section. The estimated capacity and the procedure involved in the same are very instrumental for modeling the merging behavior and evaluating network performance.KeywordsMerging sectionMixed trafficVISSIMCalibration