For transportation planners, having a broad enough body of research to inform and deliver multifaceted projects can be a challenge. While it has been determined that dedicated right-turn lanes reduce vehicle crashes and delays, their impact on pedestrian safety has not received the same level of study.
To fill this knowledge gap, University of Minnesota Human Factors Safety Lab (HFSL) research associate and CTS scholar Curtis Craig investigated driver response to pedestrians in or near crosswalks at dedicated right-turn lanes in a new project sponsored by the Minnesota Department of Transportation (MnDOT) and the Minnesota Local Road Research Board (LRRB).
“Pedestrian safety at intersections is critical, especially given the initiatives to increase livability in Minnesota’s urban areas,” Craig says. “We wanted to give state and local traffic engineers and policymakers the information they needed to evaluate and improve pedestrian safety at intersections while also maintaining vehicle mobility and safety.”
Researchers examined this issue from three angles. First, they reviewed the research literature and a crash audit on Minnesota pedestrian crash data from 2016 to 2019. Next, they conducted a field study using camera data from St. Paul intersections to compare driver behavior at dedicated turn lanes versus typical lanes where turning is permitted. This included a before-and-after study at an intersection following the installation of a dedicated right-turn lane. Finally, researchers used the HFSL’s immersive driving simulator to evaluate differences in driver behavior between dedicated and shared lanes during high-risk pedestrian crossing scenarios.
One of the study’s key findings was that pedestrian safety at a dedicated right-turn lane is significantly influenced by traffic volume. On lower-volume roads (up to 12,000 vehicles a day), dedicated right-turn lanes have a beneficial or at least neutral effect on pedestrian safety. On higher-volume roads (more than 16,000 vehicles a day), results were mixed: vehicle turning speeds were often lower, but so were yielding rates.
“We believe drivers at moderately busy intersections face more distractions and ‘efficiency pressure’ as they try to make up time from traffic slowdowns, leading to less attention to pedestrians,” Craig says. This behavior is especially critical at the crosswalk parallel to the driver’s original direction of travel, when drivers have a green light and pedestrians have a walk sign. “Drivers can overlook pedestrians as they accelerate out of a turn.”
This research provides valuable findings for state and local engineers to consider as they construct and redesign intersections. The researchers recommend evaluating pedestrian and vehicle volumes before installing dedicated right-turn lanes and considering safety countermeasures at higher-volume intersections, such as improved sightlines for pedestrian visibility, advance stop lines, and “yield to pedestrian” signs. In addition, engineers can optimize the geometry of right-turn lanes by using smaller turning radii to slow down turns.
“These findings shed light on the challenges we encounter with intersection safety,” Ramsey County Traffic Engineer Brad Estochen says. “Additional research will continue to offer valuable insight.”
Future research will refine these strategies, focusing on how to maximize pedestrian safety across a wider range of volumes and intersection designs. The full report offers a deeper look at the data and the complete list of engineering recommendations.
—Megan Tsai, contributing writer
