Evaluation of alternative Ramp Metering scenarios on freeway on-ramp with the use of microscopic simulation software Vissim

The main goals of this paper include the investigation and evaluation of alternative ramp metering scenarios on a freeway on-ramp and the development of a “smart” signal controller, with the use of PTV Vissim microsimulation software. A complex interchange on the Ring road of Thessaloniki was chosen for the implementation of this study and a drone was used to measure traffic volumes. Using the Vissim platform, a software model was created and its accuracy with respect to the existing situation was evaluated. Different scenarios were developed, and the function of the interchange was observed. In the first set of scenarios, the traffic volume was increased by certain percentage and the results were collected and examined. Next, two new scenarios with the use of ramp metering were developed and a traffic signal was placed on the on-ramp. In the first of these two scenarios, a traffic light with a fixed-time traffic program was placed, whereas in the second one, a vehicle-actuated signal light was created, with the use of the VisVAP add-on. A flow chart was generated and used to program the signal light, so that each time high traffic volume was detected by the detectors that were placed in the expressway, the red light was activated. After all the scenarios were created and examined, certain KPI’s were collected and used for the overall evaluation. The results from the use of the ramp meter, either the fixed-time or the vehicle-actuated, showed that a ramp meter can be very effective in the improvement of the traffic conditions and may have a positive environmental impact.