Most states require route surveys above a specific height threshold, while others have route survey thresholds for length, width and height. In a route survey, a surveyor drives the route with a height pole set slightly higher than the load’s maximum height to identify conflicts with overhead structures. Route surveyors also measure road widths on corners to determine if the load can pass through safely. Surveys act as the schematics for the operational planning of OSOW moves. A number of states allow carrier discretion to determine whether a route survey is needed. Other states require a route survey on a case-by-case basis or at specific thresholds.