Stopping sight distance (SSD) is the minimum sight distance required and shall be provided continuously. Decision sight distance (DSD) is desirable at interchanges, intersections, lane drops, and areas of complex decision-making. Intersection sight distance (ISD) shall be provided at all at-grade intersections. Passing sight distance applies to two-lane highways and determines no-passing zone marking. WSDOT uses the AASHTO criteria with a perception-reaction time of 2.5 seconds and deceleration rate of 11.2 ft/s².
All work under this section shall comply with WSDOT current standards and applicable AASHTO, ASTM, and federal requirements. The Engineer has authority to accept or reject materials and workmanship that do not conform to the specifications.