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Thurston Regional Planning Council (TRPC) Travel Model Peer Review Report

2.0 Thurston Regional Planning Council Overview

2.1 Thurston Regional Planning Council Responsibilities

Thurston Regional Planning Council (TRPC) is the regional planning agency for the Thurston

County, Washington region. Thurston County is located at the southern end of Puget Sound on the I-5 corridor, about 60 miles south of Seattle. TRPC and the Thurston region have a long-standing commitment to integrated transportation-land use policy and development of an integrated multimodal transportation system. The region places a high priority on system efficiency and demand management.

TRPC is the federally-designated Metropolitan Planning Organization (MPO) for the Olympia urbanized area and is also the state-designated Regional Transportation Planning Organization (RTPO) for Thurston County (see Figure 1 area in gray). TRPC conducts an MPO-compliant planning process for its full planning area--which consists of the entire County--and land use planning under Washington's Growth Management Act (GMA).

The figure provides a map of the Thurston region planning area including city limits, urban growth boundaries, the MPO boundary, geographic features, highways, and reservations.

Figure 1: TRPC Planning Area (gray-all of Thurston County, Washington). Source: TRPC

2.2 Regional Characteristics and Transportation Issues

Olympia is the Washington State capital and the TRPC region's primary city, bordered closely by the cities of Lacey to the east and Tumwater to the south. TRPC's MPO area had a population of 176,600 people in the 2010 Census while its full planning area-Thurston County-had a population of 255,000. The County had approximately 130,000 jobs in year 2010 and is one of the fastest-growing counties in Washington State.[1] Seattle and Tacoma, the two largest cities of the Puget Sound Regional Council (PSRC) MPO planning area, lie respectively 30 and 60 miles to the north while Portland, Oregon lies to the south.

With respect to transportation issues, it is first critical to note that all the cities listed above are linked by Interstate 5 (I-5) which is the most important roadway in the TRPC region and, indeed, its lifeline. US 101 is another major divided highway which carries significant amounts of traffic to and from Mason County and Washington's Kitsap peninsula on TRPC's west and northwest.Pierce County to the northeast contains the main part of Joint Base Lewis McChord (JBLM, the firing range of which actually lies within Thurston County). JBLM and Pierce County generate large amounts of travel to and from the Thurston region but lie within the PSRC planning area. I-5 in the vicinity of the TRPC/Pierce County boundary-formed by the Nisqually River, the basin of which is environmentally sensitive-is heavily congested during much of each weekday and also on the weekends during the summer tourist season. The environmental sensitivity plus state budget constraints make the contemplation of traditional capacity investments in the key I-5 corridor difficult.

The evolution of the region's urban structure and the formation of its cities prior to Washington's Growth Management Act in conjunction with rapid growth have created a network of auto-oriented arterials while at the same time the combined geography of Puget Sound, public forest land, and the JBLM firing range has constrained the routing of major freeways. These "facts on the ground" complicate the region's goal of creating transit-supportive land use in its urban areas. Simultaneously much of the TRPC region remains rural, often with a major state route as the local towns' main street, creating a separate challenge of sustaining rural mobility and livability. Finally, Olympia has a saltwater port that carries log-export-related freight movements and the region has started to see the growth of large freight distribution centers.

Within this context TRPC and its members have developed and sustained a strong transportation policy framework focused on preserving the region's environmental quality and livability. The region is committed to a vision of a fully multimodal transportation system, integrating land use policy with transportation planning, using system and demand management as a means of creating efficiencies that obviate the need for traditional roadway capacity expansion, and ultimately creating good accessibility for all the region's citizens. The sincerity of this balanced commitment can be seen in the endurance of a policy not to expand regional arterials beyond a five-lane cross-section (four travel lanes plus a center turn lane).


[1] TRPC. Travel Model Improvement Program (TMIP) Peer Review Meeting--Review of Proposed TRPC Model Improvements. Presentation for the Peer Review. June 11, 2012. Slides 17-23.

Updated: 03/28/2014
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