According to the U.S. Manual on Uniform Traffic Control Devices, how long should the WALKING PERSON signal indication be displayed at a minimum?

The minimum display time for the WALKING PERSON signal indication, as specified in the U.S. Manual on Uniform Traffic Control Devices ( MUTCD), is set to ensure that pedestrians have adequate time to safely cross intersections. The appropriate time is determined based on factors like the average walking speed of pedestrians, which is typically considered to be around 3.5 feet per second.

In this context, the 7 seconds minimum duration allows enough time for a typical pedestrian to start crossing the street safely. This duration helps to account for the time it takes to recognize the signal change and begin crossing, aiming to reduce conflicts between pedestrian and vehicle movements, thus enhancing safety for those on foot.

Other durations, while possibly adequate in certain situations, do not align with the standardized minimum required by the MUTCD for general application in most scenarios. Therefore, the choice of 7 seconds is justified as providing a balance between the need for clear pedestrian guidance and safety at crosswalks.