What is the pedestrian crossing design speed used to size gaps?

• A. 2.0 ft/s
• B. 4.0 ft/s
• C. 6.0 ft/s
• D. 3.0 ft/s

Answer: (D)

The main idea is that gaps in traffic are sized using the speed at which a pedestrian is assumed to cross the street. This crossing speed directly determines how long it takes a pedestrian to traverse the crosswalk, which in turn sets the required vehicle gaps to allow safe crossing. The value commonly used for this design speed is 3.0 ft/s (about 0.9 m/s). This pace represents a conservative, typical walking speed that covers a wide range of pedestrians, including slower walkers, and yields a crossing time long enough to be safe.

If you used a faster speed like 4 ft/s, the crossing time would be shorter and the required gaps would be smaller, potentially unsafe for slower pedestrians. A much slower speed (2 ft/s) would make crossing times very long and gaps overly large. A brisk 6 ft/s isn’t realistic for the general population. So 3.0 ft/s is the best, most common balance for sizing pedestrian gaps.