How many seconds should a minor street through phase typically last?

Answer: B — 5 to 15 seconds

The duration of a minor street through phase is generally set to last between 5 to 15 seconds. This timing is designed to minimize delay for vehicles waiting at the intersection while ensuring that sufficient time is provided for vehicles traveling on the minor street to clear the intersection safely. Choosing a phase duration within this range strikes a balance between allowing adequate time for minor street traffic to pass through and maintaining the flow of main street traffic. A phase that lasts too short could lead to congestion and frustration for drivers on the minor street, while a phase that lasts too long may cause unnecessary delays for heavier traffic on the main street. The other options represent durations that are either shorter than advisable or longer than necessary for typical minor street conditions, which could lead to inefficiencies in traffic flow. Thus, the selection of 5 to 15 seconds is aligned with industry best practices to ensure effective traffic management at intersections.