What does a one way sign indicate?

Answer: B — Traffic must proceed in one direction only

A one way sign is a regulatory sign that indicates traffic must proceed in one direction only. This means that all vehicles traveling on that road must go straight in the direction that the sign indicates, and no traffic is allowed to move in the opposite direction. This is important for maintaining safe traffic flow and reducing collisions by ensuring that drivers are aware of the correct direction to follow. In contrast, the other choices suggest scenarios where traffic could operate differently. Traffic moving in both directions would not be appropriate for a one way sign, and allowing drivers to choose their direction contradicts the purpose of the sign, which is to provide clear and enforceable guidance. Additionally, stating that only pedestrian traffic is allowed does not apply here, as a one way sign is specific to vehicle traffic and does not restrict pedestrian access in this way.