Which distance is applicable specifically on two-lane highways?

The concept of Passing Sight Distance is particularly relevant on two-lane highways due to the nature of traffic flow and the need for safe overtaking. On these roads, where traffic in opposing directions share a single lane, adequate passing sight distance allows a driver to safely accelerate and pass vehicles traveling in the same direction while ensuring visibility of oncoming traffic.

This distance calculation plays a critical role in highway design, as it directly influences the safety and efficiency of overtaking maneuvers. If this distance is insufficient, it can lead to dangerous situations where a driver misjudges their ability to safely complete a passing maneuver before encountering oncoming vehicles, thereby increasing the likelihood of head-on collisions.

In contrast, Stopping Sight Distance focuses on the distance required for a driver to perceive a hazard and come to a complete stop, which is important on all types of roads but not exclusive to the dynamics of two-lane highways. Decision Sight Distance pertains to the distance required for a driver to make complex decisions, often involving turns and other maneuvers, typically in more complex traffic situations or intersections rather than straight two-lane roadways. Average Annual Daily Traffic (AADT) is a measure of traffic volume and is not directly related to physical distances or visibility on