Sight Distance Survey is a method of aiding engineers in determining the decision sight distance required to safely pass a slow moving vehicle, based on Manual on Uniform Traffic Control Devices (MUTCD) standards. It uses the unobstructed sight distance of a vehicle measured at 3.5 feet above the roadway to a target on the back of a van.

The tracking vehicle records the mileposts where the target begins no sight and ends no sight. The engineers then decide what other factors would affect the safety of the motorist exercising reasonable care for their own protection and may stripe the county road or State highway accordingly.

The data contained in WSDOT Sight Distance Survey is based on the current MUTCD standard for sight distance. Local or county standards may vary. Existing roadways are only required to meet the standards applicable at the time the roadway was constructed. Decisions to re-stripe will be affected by the applicable standards, available resources, and other factors.