Abstract:
Employment of traffic simulation tools has become a popular practice in traffic operations analyses as the transportation system has become more complex and more frequently congested. Most of the commercially available traffic simulation models work best for free-flow or unsaturated conditions. Depending on the type of traffic condition and type of analysis, the performance of simulation models varies and there is little information available to help the analyst to select the most appropriate and accurate model for a given analysis. To address this need, two traffic simulation tools, SimTraffic and AIMSUN, were evaluated and compared for a congested arterial segment. Both simulation packages are designed to model almost any combination of surface street and freeway facilities. In this paper, an arterial segment in Tuscaloosa, Alabama (McFarland Boulevard) between 13th street and 31st street was coded and simulated for AM, Mid day, and PM peak periods. The network was simulated 10 times for each peak period using both simulation models, and average values were taken for comparison. Then the network was evaluated using output measures of effectiveness (MOE) such as Vehicle Hours Travel (VHT), Vehicle Miles Travel (VMT), average speed, and flow rate at the network level, along with delay, travel time, and average speed at the arterial level, and delay and traffic volume at a link level. Using statistical methods and graphical plots for comparison, each simulation model was evaluated for its capability to replicate existing field conditions using default and calibrated traffic parameters. In addition to accuracy, the models were also compared with respect to ease of coding, and quality/usefulness of output. This report documents relevant results and calibration processes used for employing the models in future studies and practices regarding congested arterials.
