West Seattle has a stake in a transportation proposal approved by the three-county Regional Transportation Investment District Planning Committee last week.

If voters agree this fall, money would be included to widen the Spokane Street Viaduct and build a new off-ramp at Fourth Avenue South. There are also plans to construct a rail yard overpass on Lander Street in the Sodo. In addition, the South Park Bridge over the Duwamish would be replaced.

Those are three of many construction projects in a regional transportation package scheduled to go before voters this fall in King, Pierce and Snohomish counties. They will join bus and light-rail projects being separately proposed to voters by Sound Transit.

Widening the Spokane Street Viaduct has been a longtime goal of the city, which owns the elevated highway. Its lanes are narrow and its off-ramps substandard. The viaduct - which connects West Seattle to Interstate 5 - also lacks road shoulders and breakdown areas.

The Regional Transportation Investment District Planning Committee proposes expanding the number of lanes on the Spokane Street Viaduct. The money would build a new eastbound off-ramp at Fourth Avenue South for buses as well as cars and trucks. Buses could then get over the railroad tracks and be in better position to enter downtown Seattle on the busway.

A new on-ramp for westbound traffic on the Spokane Street Viaduct would be built at First Avenue South.

Traffic in and out of the Duwamish manufacturing and industrial area could be improved by building an overpass on South Lander Street in the Sodo area. The overpass would carry cars and trucks above the railroad tracks from First to Fourth avenues south. As it is now, cars and trucks are frequently delayed on Lander Street by passing Burlington Northern-Santa Fe trains.

The Lander Street overpass would serve as an alternative to State Route 519.

The new overpass also would be used by the planned bus rapid-transit system and be near a Link light rail station expected to be frequented by West Seattle residents. The station is planned at Lander Street and Fifth Avenue South.

Widening the Spokane Street Viaduct and building the Lander Street overpass combined with another project to widen Mercer Street, would total approximately $289 million.

The Regional Transportation Investment District Planning Committee was created by the Washington Legislature to keep people and commerce moving through the most dense parts of King, Snohomish and Pierce counties. It's supposed to focus on the most congested highways and bridges in the three-county area and either add to or finish work on state highway projects.

Projects recommended by the Regional Transportation Investment District are designed to affordably improve traffic flow, safety and "performance," according to the agency's website. Its projects also integrate roads and transit projects that benefit the most people.

The county councils of King, Pierce and Snohomish counties must each approve the final list of projects before it goes to the voters. County approval seems likely because the members of the three county councils also comprise the Regional Transportation Investment District Planning Committee, which is proposing the package of construction projects. The Regional Transportation Investment District Planning Committee approved the voter package on a 19-2 vote, so county approval seems likely.

Many of the proposed projects in the Seattle area would be built before the Alaskan Way Viaduct is torn down and replaced.

This autumn, it will be up to voters living in the three counties to decide whether to tax themselves to pay for the approximately $4 billion in regional transportation investments. The money would be combined with King County's Transit Now program and the city of Seattle's Bridging the Gap campaign, both of which were approved by voters last fall.

Other proposed projects that could affect West Seattle include a proposal to build a new exit ramp for high-occupancy vehicles on northbound Interstate 5 to Spokane Street via South Industrial Way. It would cost an estimated $83 million (in 2006 dollars).

A new South Park Bridge is included because the existing span is so deficient it's scheduled to be closed in three years if no funding comes available to replace it. A new parallel bascule drawbridge is planned at a cost of $99 million.

The transportation package also proposes to improve freight movement by extending the southern end of State Route 509. A four-lane, freight-only road would be built from South 188th Street in Burien to 210th Street in SeaTac city, where it would connect to Interstate 5.

Some additional lanes also would be added to I-5, from the Kent-Des Moines Road to 320th Street in Federal Way. These changes in south King County are estimated to cost about $798 million.

Tim St. Clair can be reached at timstc@robinsonnews.com or 932-0300.