Case Study:

Portland, Oregon

Context

The I-5 Corridor

I-5, the only continuous highway between Mexico and Canada on the West Coast, directly serves regional and state economies in Washington, Oregon, and California. Within the Portland/Vancouver metropolitan area, I-5 is the north-south backbone of regional trade, intersecting with two east-west transcontinental railroads, deep-water shipping and upriver barging, and providing primary access to the region's two ports and regional warehousing and distribution facilities. Figure 1 shows the I-5 study corridor and major transportation facilities.

Figure 1. Portland I-5 Study Corridor

Domestically trucks carry 75 percent of the goods shipped to or from other states, and north and south truck movements in and out of the Portland/Vancouver region account for the majority of annual truck freight volumes (Parsons Brinckerhoff, 2000). Yet the ability of I-5 to provide freight mobility within and beyond the region is increasingly threatened by traffic congestion. The Texas Transportation Institute (TTI) currently ranks the Portland/Vancouver metropolitan areas as the 12^th most congested in the nation, with I-5 being one of the most congested facilities in the region. In addition, congestion is projected to worsen substantially with rapid population growth and increases in vehicle-miles of travel (VMT) per capita. For example, congestion at the I-5 Columbia River bridge is expected to create six- to seven-mile peak direction queues during the morning and afternoon peak periods in 2020, if no improvements are made.

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