InterchangeSE: Multimodal, Virtual Reality Traffic Simulation
Federal Highway Administration | Iowa State University
Role: Lead User Researcher
Problem Statement
In 2013, congestion cost the U.S. economy $124 billion, which is expected to reach $180 billion by 2030. Further, the societal cost of traffic crashes in the U.S. exceeds $900 billion each year. Congestion can be mitigated by road management technologies, advanced optimization tools, and automated vehicles on the road. However, in order to develop these kinds of solution a traffic simulation testbed to rapidly design, prototype, and test solutions is necessary.
Extended reality (XR) and advanced traffic simulation technologies offer potential solutions to these issues by allowing complex roadway systems with mixtures of human and autonomous vehicles to be analyzed. As autonomous vehicle technology becomes more pervasive across the Department of Defense, simulation of such complex multimodal scenarios is critical. InterchangeSE is a platform that facilitates this complex, multimodal simulation in a risk-free environment. InterchangeSE allows a variety of complex simulated scenarios involving live and virtual participants (e.g., drivers, traffic managers, pedestrians, autonomous vehicles) to be authored and run in varying degrees of immersion.
However, to determine the feasibility of this platform, it must be tested with users. To do so, a within-between subject 2 scenario (suburban, urban) x 3 simulator (pedestrian, bicycle, car) experiment was conducted.
The Setup
Within InterchangeSE, physical participants interact with each other using a variety of displays including multiple computer monitors, commercially available HMDs, and augmented reality displays. Driving parameters from the physical participants, such as position and heading, are network synchronized with traffic (i.e., vehicles and pedestrians) and computed by a traffic simulator. Participants "enter" the environment using one of three simulators: a car simulator, a bicycle simulator, or a pedestrian simulator. Car drivers and pedestrians see the virtual world through HMDs while cyclists see the world on large screens.
Bicycle simulator (left) and car simulator (right)
Procedure and Measures
Participants were tasked with navigating a predetermined path around the environment for seven minutes while obeying traffic laws. Navigation was communicated to the users through a satnav map displayed between the handlebars, on the dashboard, or as a handheld map depending on simulator.
The evaluation assessed the user experience when using the system, as well as the system performance. The user experience was assessed with a series of subjective questionnaires and objective performance data.
Measures used in the study
Results
The goal of the InterchangeSE platform is to create a test bed that is realistic enough to be a valid testing environment for new technologies. In the evaluation of InterchangeSE, users reported high levels of presence and efficacy while registering low to moderate workload. These results indicate that the platform is a promising option for testing traffic and roadway technology. Users are feeling immersed in the environment and empowered to take action as they would in the real world.
Presence
Efficacy
Workload
The Future & Challenges
When evaluating any product, the question is always "where do we go from here?" In the case of this platform, it is packaged and ready for implementation by the client. Future development and testing could refine the environment, but would be most effective if conducted in conjunction with scenario-specific requirements.
The challenge in this project was in its size and scope. When simulating a traffic environment, everything from traffic patterns to weather need to be accounted for. When simulating such an environment for real-life inputs (e.g. a human cyclist on a real bike), the challenge grows. Bringing this simulation environment and its evaluation to the finish line was an incredible multidisciplinary effort.