Washington State Route 510

Washington State Route 510
State	WA
Type	SR
Route	510
Length mi	11.0
Established	1964
Direction a	West
Terminus a	Olympia
Direction b	East
Terminus b	Yelm
Counties	Thurston County

Washington State Route 510

Washington State Route 510 is a state highway in Thurston County connecting the state capital Olympia with the city of Yelm and communities near Rainier and Tenino. The route serves commuter, commercial, and freight traffic between Interstate 5, regional arterials, and local roads that link to Joint Base Lewis–McChord, Fort Lewis, and recreational destinations such as Nisqually National Wildlife Refuge and the Capitol State Forest. Established in the 1964 renumbering, the highway plays a strategic role in the South Puget Sound transportation network.

Route description

SR 510 begins in westbound adjacency to U.S. Route 101 and Interstate 5 ramps near downtown Olympia and proceeds east as a multilane arterial through neighborhoods that abut Percival Landing and the Washington State Capitol. The corridor crosses the Nisqually River tributaries and traverses suburban corridors adjacent to Tumwater and industrial areas with rail connections to BNSF Railway and Port of Olympia. East of Yelm Prairie, the highway narrows and curves through mixed residential and agricultural areas toward Yelm, intersecting with county roads that provide direct access to Nisqually Indian Tribe lands and the Black Hills foothills. The eastern terminus interfaces with local arterials serving Fort Lewis access points and commuter flows toward Puyallup and Tacoma.

Along its length SR 510 crosses or parallels several named facilities and corridors including rail lines used by Amtrak, rights-of-way formerly associated with historic Northern Pacific Railway routes, and state-managed waterways tributary to the Nisqually River Delta. The highway is designated to facilitate both passenger vehicles and heavy truck movements that support commerce to regional distribution centers and agriculture sectors near Tenino.

History

The corridor that became SR 510 traces origins to territorial-era roads and wagon routes serving Hudson’s Bay Company-era settlements and later Washington Territory communities. Early improvements occurred during the Good Roads Movement and under state highway programs enacted in the early 20th century, with alignments reflecting connections between Olympia and inland logging and farming districts tied to the Washington State Ferries-era economy of the South Puget Sound.

In the 1930s and 1940s the alignment was upgraded as part of state expansion projects reflecting demand from timber and wartime mobilization to Fort Lewis and neighboring military installations. The formal designation in the 1964 statewide renumbering placed the route within the modern numbered system alongside Interstate 5 and other primary routes. Subsequent decades saw incremental widening, intersection improvements, and safety projects influenced by federal funding programs administered during the administrations of presidents such as Lyndon B. Johnson and Richard Nixon that expanded highway investment nationwide.

Notable local improvements in the late 20th and early 21st centuries included reconstruction near Olympia to serve growth associated with the Washington State Capitol complex and commuter traffic to Joint Base Lewis–McChord. Community stakeholders including Thurston County officials, the Washington State Department of Transportation, and municipal governments in Tumwater and Yelm have periodically collaborated on traffic-calming, interchange reconfiguration, and preservation of nearby natural areas such as the Nisqually River Delta.

Major intersections

The highway’s principal junctions include its western connection near Interstate 5 and U.S. Route 101 in Olympia; intersections with regional arterials providing access to Tumwater and Yelm neighborhoods; crossings of county roads leading to Tenino and Rainier; and its eastern terminus providing continuity to local streets that feed toward Joint Base Lewis–McChord and Puyallup. These intersections serve commuters bound for Tacoma, commercial freight movements to the Port of Olympia, and recreational traffic to the Capitol State Forest and regional parks. Signage at major junctions is coordinated with the Washington State Department of Transportation and municipal traffic authorities to integrate with regional travel demand.

Traffic and usage

SR 510 supports a mix of peak-period commuter flows, off-peak commercial freight, and seasonal recreational travel. Average daily traffic volumes vary along segments, with the highest counts adjacent to Olympia and near interchange ramps to Interstate 5, reflecting commuter patterns tied to employment centers in Olympia, Tacoma, and Joint Base Lewis–McChord. Freight usage links regional agricultural producers and distribution facilities to the Port of Olympia and transshipment nodes served by BNSF Railway and highway connections to U.S. Route 12.

Safety and congestion analyses performed by the Washington State Department of Transportation and Thurston Regional Planning Council have identified specific bottlenecks and crash-prone intersections, prompting targeted countermeasures. Transit providers such as Intercity Transit and regional shuttle services operate along or adjacent to the corridor, supplying commuter and access services to employment centers and military installations.

Future plans and improvements

Planned improvements emphasize capacity, safety, multimodal access, and environmental mitigation consistent with regional growth forecasts from agencies like the Puget Sound Regional Council and Thurston Regional Planning Council. Proposed projects range from targeted intersection upgrades and left-turn lane additions to corridor widening near Olympia and pedestrian-bicycle facility enhancements linking to Capitol Lake and regional trail systems that interconnect with Chehalis Western Trail corridors.

Environmental reviews conducted under state-level statutes and federal frameworks have guided design choices to protect wetlands associated with the Nisqually River Delta and to coordinate wetlands mitigation with the Nisqually Indian Tribe. Funding strategies include state transportation budgets, local levies approved by voters in Thurston County, and grants from federal programs administered through agencies such as the Federal Highway Administration.

Category:Roads in Washington (state)