Sight Distance Survey

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. Each vehicle has a distance measuring instrument (DMI), a computer and a modem that enables the operators to maintain a preset distance based on the existing speed limit. The computers make a comparison between the DMI readings and communicate the results with each other through RF radio signals. 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. Customers receive a digital and hard copy report of the entire survey showing the beginning and ending of each zone. Email the Roadway Systems Branch Manager or call by phone at (360) 570-2369 for details.

Disclaimer: 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.

This File Requires The Adobe Reader For Viewing

Portable Document Format (.PDF) files require the free Adobe (tm) Reader.
Download the Adobe Reader by clicking the graphic below.