SUMO2Unity: An Open-Source Traffic Co-Simulation Tool to Improve Road Safety

In traffic safety research, simulation tools are considered more straightforward and cost-effective than direct observations of real-world conditions, especially when dealing with scenarios that may not exist in reality. The tools include traffic micro-simulation tools (e.g., SUMO) and driver simulators developed in game engines (e.g., Unity). However, the tools also have limitations. For example, the equations used to simulate human behavior may not always reflect real-world behavior accurately, and driver simulators’ lack of realistic traffic systems affect the interaction between the simulator vehicle and other vehicles. Co-simulation allows two different simulation tools to exchange data to enhance the capabilities of each tool, but many traffic safety researchers currently spend significant amounts of time, effort, and budget working on their own version of a co-simulation tool to integrate, for example, a traffic micro-simulation tool such as SUMO with a driver simulator such as the Unity game engine. This situation takes time away from focusing on the goal of improving traffic safety. In this paper, we developed an open-source traffic co-simulation tool. Development involved three tasks: 1. integration of SUMO and Unity; 2. development of a 2D and 3D environment (a 3D road environment in Unity was generated from a 2D road environment in SUMO); and 3. development of a 3D model of a simulator vehicle and development of a VR-based driver simulator. We named our tool SUMO2Unity and believe that it can significantly help traffic safety researchers to conduct future research aimed at improving traffic safety.