What is the function of white lane lines on the road?

White lane lines on the road serve the important function of separating lanes of traffic that are moving in the same direction. This helps to maintain order on the roadway and ensures that drivers are aware of the designated lanes for their travel. By adhering to these lane lines, drivers can safely navigate without encroaching on other vehicles' paths, reducing the likelihood of accidents.

The other options, while they describe different road markings or features, do not accurately represent the role of white lane lines. For example, lane lines that separate traffic going in opposite directions would typically be yellow, while pedestrian walkways or crosswalks are often indicated by distinct markings or signage. Speed limits are usually posted on signs rather than indicated by lane markings on the road. Understanding the specific purpose of these markings is crucial for safe driving practices.