What is the purpose of lane markings on the road?

Lane markings on the road are primarily designed to regulate traffic flow. They serve as visual guides for drivers, indicating where they should position their vehicles within a lane and how to navigate intersections safely. For instance, solid lines often indicate that lane changes are prohibited, while dashed lines allow for safe passing. By providing clear instructions on the proper use of different lanes, these markings help maintain an orderly flow of traffic, enhance safety, and reduce the likelihood of accidents.

The other options do not accurately reflect the primary function of lane markings. For example, lane markings do not separate vehicles by size, nor do they indicate speed limits or mark pedestrian crossings, which are designated by other means such as signs or crosswalks.