What does a double solid yellow line in the center of the road signify?

A double solid yellow line in the center of the road indicates that passing is not allowed in either direction. This road marking is used to enhance safety by preventing vehicles from crossing the lines to pass other vehicles, which could lead to head-on collisions or accidents. The presence of double solid lines emphasizes the importance of staying in your lane and adhering to the traffic rules designed to keep all road users safe.

The other options provide different scenarios that do not accurately describe the function of double solid yellow lines. For instance, allowing passing in one direction or specifying single-file traffic misinterpret the regulatory role of the marking, and mentioning pedestrian crossings introduces a feature unrelated to the purpose of the double lines.