PROVIDING TWO-WAY HOV AND TRANSIT PRIORITY IN A COMPLEX URBAN CORRIDOR

With the 1996 voter approval of a plan and funding for a regional transit initiative, the Pugent Sound Region embarked on implementation of a high-capacity transit program that includes bus, light rail, and commuter rail components. To implement and administer the regional transit program, the Washington State Legislature passed enabling legislation that created a new three-county regional transit authority, no know as Sound Transit. The bus component of the system, Regional Express, includes transit service and facilities such as transit centers and park and rides as well as a series of enhancements to the lanes currently operated by the Washington State Department of Transportation (WSDOT). These enhancements are intended to transform the existing lane system into an HOV Expressway that will include in-line stations and direct access connections. One set of projects, the Mercer Island Project Group, includes transit improvements to the I-90 corridor between Seattle and Bellevue, crossing Lake Washington via Mercer Island. Three elements comprise this set of projects: (1) Provisions for improving the reliability of two-way transit operations on I-90; (2) A transit station on Mercer Island, in or adjacent to the I-90 right-of-way; and (3) Additional park-and-ride spaces on Mercer Island. For the project, Sound Transit and their partners, the Washington State Department of Transportation, City of Mercer Island and King county/Metro Transit, have assembled a multi-agency, multi-consultant team that represents an integration of environmental analysis, transportation planning, traffic engineering, and highway design skills into a process intended to identify improvements to I-90 and to provide reliable two-way transit operations while minimizing impacts to other I-90 users: carpools, Mercer Island traffic, general purpose traffic and freight. The focus of the project includes sensitivity to the myriad of issues not found in a traditional freeway design project.