How is the clear zone measured in relation to the traveled lane?

The clear zone is a defined area adjacent to the traveled lane that is unobstructed and free of hazards, providing a safe space for errant vehicles to recover. It is critical for reducing the risk of collisions and improving overall road safety. The measurement of the clear zone begins at the edge of the traveled lane, extending outward to ensure that there are no obstacles that could potentially impede the safe recovery of vehicles.

Measuring from the edge of the traveled lane establishes a consistent and safety-focused approach, as this is where vehicles typically operate. By ensuring that this area is clear of obstructions, such as fixed objects, steep slopes, or debris, road designers and traffic control supervisors can enhance the safety of drivers who may drift from their lanes. This measurement guideline aligns with best practices outlined in traffic safety guidelines and standards.

Choosing to measure from other reference points—like the center of the road or the shoulder—could lead to inconsistent and potentially unsafe conditions, as it may not accurately reflect the space required for vehicle recovery. Thus, understanding the clear zone and its measurement from the edge of the traveled lane is essential in traffic control and road safety planning.