What characteristic must a highway have to be classified as a controlled access facility?

A highway is classified as a controlled access facility if it is designed to allow for uninterrupted traffic flow, prioritizing safety and efficiency. One of the primary characteristics that supports this classification is having a sufficient number of travel lanes to accommodate high volumes of vehicles, which is essential for maintaining continuous traffic flow at higher speeds.

The requirement for a minimum of three travel lanes, excluding access roads, is crucial because it allows for multiple lanes for vehicles traveling in the same direction. This configuration enables smoother traffic movement, reduces bottlenecks, and facilitates overtaking, all of which contribute to the controlled access nature of the highway. The presence of three lanes also provides greater flexibility for handling various traffic conditions, especially during peak travel times.

In contrast, highways that do not meet this lane requirement may not effectively handle the high traffic volumes typical of controlled access facilities, leading to congestion and increased accident risks. Thus, the requirement for a minimum of three travel lanes is a defining factor in classifying a highway as a controlled access facility.