Evaluation of Advanced Vehicle and Communication Technologies through Traffic Microsimulation
Lily Elefteriadou, University of Florida
Michael Hunter, Georgia Institute of Technology
Chelsea White II, Georgia Institute of Technology
- UTC Project Info
- Final Report
- Final Report (update)
- Technology Transfer Report
- Project Brief – Simulation Extension to Evaluate the Impact of CAVs on Traffic Congestion & Emissions
Proper evaluation of traffic operations integrating Connected and Autonomous Vehicles (CAVs) requires accurate representation of these emerging technologies within the context of microscopic simulation, allowing for detailed evaluation of their operational and environmental effects. To accomplish this, the objectives of this project were:
1. Evaluate the microscopic simulator VISSIM’s ability to simulate CAVs
2. Develop a comprehensive simulation extension to represent CAVs in VISSIM
3. Integrate emissions modeling to calculate real-time energy and emission estimates
4. Assess traffic operational and environmental performance measures for various levels of CAVs.
Evaluation of VISSIM revealed that internal modeling of CAVs has several limitations. For external modeling, two VISSIM interfaces are useful. The Component Object Model (COM) Application Programming Interface (API) is the superior approach for fetching data and modeling connectivity, whereas the External Driver Model (EDM) is a better tool for lateral and longitudinal control. Utilizing both the COM API and EDM overcomes the disadvantages of both, creating a more robust platform for CAV modeling.
Based on this, a comprehensive simulation extension was developed to represent CAVs in VISSIM. CAVs were modeled and an isolated signalized intersection was simulated. The trajectory data from VISSIM were leveraged to estimate energy, fuel consumption, and greenhouse gas emissions using the Motor Vehicle Emission Simulator (MOVES) method.
The results show that CAVs in the traffic stream result in net improvement in traffic operational measures (travel time and speed). CAV, the combination of the two technologies (i.e. autonomy and connectivity) yields better performance than each (CV and AV) on their own. However, emissions did not follow the same trend. While increasing AV penetration rates resulted in emissions reductions, increasing CV and CAV penetration rates resulted in higher emissions.
A deeper analysis into the root cause for these trends showed that while the CV logic chosen for testing in the VISSIM simulation environment seeks to maximize the likelihood of vehicle arrival-on-green, the algorithm likely results in increased variations in second-by-second accelerations, leading to overall higher emissions.
The results are based on a small and relatively simple network, and operations may be different for larger and more complex networks. In addition, the AV, CV, and CAV findings are limited to the connectivity and autonomy algorithms tested in this project. A more complex network with varying vehicle movement algorithms would allow for a more robust analysis.