Configure Automated Shuttle Speed and Signaling Systems to Improve Shuttle interactions with Nearby Drivers.
Analysis of a Low-Speed Automated Shuttle Operating in Rochester, Minnesota, Suggested Ways to Reduce Risky Overtaking by Other Vehicles.
Rochester
Assessment of Pedestrian Safety and Driver Behavior Near an Automated Vehicle
Summary Information
The Med City Mover (MCM) was a Minnesota Department of Transportation-led one-year demonstration project that tested two low-speed (11 mph approximate top speed), automated shuttles in downtown Rochester, MN. This project, which took place in the spring and summer of 2022, aimed to assess driver behavior in proximity to the MCM, particularly regarding when the shuttle was yielding to pedestrians at signalized and unsignalized crosswalks. With the introduction of low-speed, automated shuttles into mixed-fleet conditions, it is critical to understand the ways in which their presence, speeds, and communication strategies may change other road users’ behaviors in ways that may be unintended and counter to safe and successful deployments.
The project offered two key areas in which nearby driver performance around a shuttle such as the MCM could be improved.
- Increase shuttle speeds to reduce overtaking risk. As shown via the study conducted at the Minnesota State Fair, lower speeds result in overtaking behaviors. Increasing the shuttle’s speed to better match the natural flow of traffic is a potential method in reducing overtaking risk. Alternatively, separate low-speed automated vehicles from moderate-to-high volume traffic corridors, particularly those with significant pedestrian activity or average speed differentials.
- Adjust the machine-human signaling interface to better communicate shuttle behavior. In the crowdsourcing study and the driving simulation study, the results indicated confusion regarding the shuttle’s hazard signaling system, used when manually yielding to pedestrians. Using a turn signal or no signal outside the standard brake lights, more consistent with how other vehicles signal in similar yielding situations, could reduce overtaking by other vehicles, as could a LED screen with text/icons.
