Southern section near Downtown
Vancouver The southern section of SR 501 and the Erwin O. Rieger Memorial Highway begins as the four-lane Mill Plain Boulevard at a
diamond interchange with
I-5 in Downtown
Vancouver. The highway travels west through Downtown Vancouver and splits into a
one-way pair on Mill Plain Boulevard and 15th Street before rejoining as Mill Plain Boulevard. SR 501 crosses a
BNSF rail yard and enters the
Port of Vancouver, becoming the Lower River Road and narrowing to a two-lane highway on the south side of
Vancouver Lake. The highway follows the
Columbia and
Lake rivers north past the
Shillapoo Wildlife Recreation Area, ending south of
Post Office Lake in the
Ridgefield National Wildlife Refuge. Every year, the
Washington State Department of Transportation (WSDOT) conducts a series of surveys on its highways in the state to measure traffic volume. This is expressed in terms of
annual average daily traffic (AADT), which is a measure of traffic volume for any average day of the year. In 2011, WSDOT calculated that the busiest section of SR 501 overall was west of I-5 at C Street, serving 13,000 vehicles, while the least busiest section of SR 501 overall was south of Shillapoo Wildlife Recreation Area, serving 650 vehicles. Between I-5 and the Port of Vancouver, SR 501 is designated as part of WSDOT's Highway of Statewide Significance, which include
interstate highways and other
principal arterials that are needed to connect major communities in the
state of Washington.
Northern section The northern section of SR 501 within
Ridgefield begins as Pioneer Street at an intersection with Main Avenue at the Ridgefield City Hall. Every year, WSDOT conducts a series of surveys on its highways in the state to measure traffic volume. This is expressed in terms of AADT, which is a measure of traffic volume for any average day of the year. In 2011, WSDOT calculated that the busiest section of the northern section was the I-5 interchange, serving 11,000 vehicles, while the least busiest section was the intersection with Main Street in Downtown Ridgefield, serving 3,200 vehicles. As of July 6, 2024, the Northern Section between the western Ridgefield City Limits and the eastern terminus at Interstate 5 was transferred to the City of Ridgefield through the Route Jurisdiction Transfer process, enacted by House Bill 2318, unanimously approved by the 68th Legislature 2024 Regular Session, and signed into law by Governor Jay Inslee on March 13, 2024. (https://lawfilesext.leg.wa.gov/biennium/2023-24/Pdf/Bills/Session%20Laws/House/2318.SL.pdf?q=20241215075257) (https://ridgefieldwa.portal.civicclerk.com/event/645/files/attachment/798). ==History==