What is the function of a solid yellow line?

A solid yellow line serves to separate lanes of traffic moving in opposite directions. Its primary function is to communicate to drivers that passing or changing lanes across this line is discouraged or prohibited due to safety concerns, often in areas where visibility is limited or where conditions warrant caution. This ensures that vehicles remain in their respective lanes, promoting safe driving practices and reducing the risk of head-on collisions.

While other options might refer to important aspects of road signage and markings — like bicycle lanes, pedestrian crossings, and parking restrictions — these do not pertain to the function of a solid yellow line. These functions are represented by different types of line markings or signs, each designed to convey specific rules and guidance to drivers and pedestrians.