The International Boulevard project is located within the City of SeaTac in King County, Washington. King County, which includes the City of Seattle, is the most populous county in Washington. The City of SeaTac, incorporated in 1990, has an area of roughly 16 square miles and a population of about 23,000. Seattle-Tacoma (Sea-Tac) International Airport is located within the SeaTac city limits.
The newly incorporated City developed Comprehensive and Transportation Plans that established land-use goals and proposed transportation facility improvements. The City was designated as an urban center under the State's Growth Management Act and under that designation was identified for substantial increases in the development density along the City's existing commercial corridor. This development follows the International Boulevard corridor. Existing land uses include some of the region's largest motels, Sea-Tac International Airport, office towers, airport-related rental car and park-and-fly facilities, and other retail uses. The Transportation Plan proposed expansion of International Boulevard to increase traffic capacity and improve pedestrian access.

International Boulevard is a major north/south arterial that serves local and regional traffic within the City of SeaTac, Washington (see Figure 2). International Boulevard, is part of signed State Route 99 (SR 99) which spans three counties and over 50 miles from South Snohomish County to North Pierce County. Prior to the construction of the Interstate System, SR 99 was a major Pacific-coast route spanning Washington, Oregon, and California. Today, that portion of SR 99 within the Puget Sound region serves as a regional link between cities and as a major route to Sea-Tac Airport, with access to the terminal and airport parking. It is also a part of the State's urban arterial system, and has been designated as a National Highway of Significance, as well as an emergency evacuation route.

Average 1992 daily traffic volumes on International Boulevard varied from 31,600 vehicles per day (vpd) at South 170th Street to over 40,000 vpd at South 188th Street, with the highest daily traffic volumes (over 42,000 vpd) occurring directly adjacent to the airport entrance.

Problem to be Solved

The project described in this case study is the first of these segments, from South 188th Street to South 170th Street. This section of International Boulevard fronts Sea-Tac Airport. Sea-Tac Airport and International Boulevard serve as a gateway to the United States and Puget Sound region for many visitors from around the world. International Boulevard has experienced significant traffic congestion, substantive safety problems, inadequate pedestrian facilities, and unsightly commercial strip development. Solutions to the transportation problems were sought that would promote and enhance re-development of the corridor as an attractive gateway.

Further Reading:
   Washington SR 99--International Boulevard