Standard cross section elements include traveled way, shoulders, medians, slopes, and clear zones. WSDOT standard lane width is 12 feet for design speeds ≥50 mph and 11 feet for lower speeds. Shoulder widths: Interstate 10 ft paved; arterial 8 ft; collector 4-6 ft. Median widths determined by access control requirements and barrier warrant analysis per the AASHTO Roadside Design Guide.
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.
Source: WSDOT Highway Design Manual, 2024 Edition. Pages 9–10 of 37.