Evaluation of Static and Dynamic No Right Turn on Red Signs at Traffic Signals

Summary:

Preventing right turns on red at signalized intersections with fixed No Right Turn on Red (NRTOR) signs can protect pedestrians trying to cross the street. If no pedestrians are present, however, preventing right turns can impede traffic. Dynamic signs that can be activated by pedestrians or at certain times of the day offer a potential solution. MnDOT wanted to compare the effectiveness of dynamic and static NRTOR signs in encouraging driver compliance. Researchers analyzed over 4,500 hours of video data from intersections with either dynamic or static signs preventing right turns on red at traffic signals. Dynamic signs were not more effective than static signs at increasing the number of drivers not turning right on red. However, adding a dynamic sign to an intersection without any sign appeared to increase pedestrian visibility to drivers. Most drivers not complying with the dynamic signs made right turns after pedestrians crossed the road. Finally, a NRTOR sign activated by time of day demonstrated a clear traffic flow benefit.

Final Deliverables:

• Evaluation of Static and Dynamic No Right Turn on Red Signs at Traffic Signals (Report #2024-17)
• Comparing the Effectiveness of No-Right-Turn-on-Red Sign Types at Traffic Signals (Research Summary)

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