» The Green Line, providing service to Clackamas County, will open Saturday.

Portland’s light rail expansion program will complete its most recent phase tomorrow, as trains on the city’s fourth line will make their way from downtown to Clackamas County along a right-of-way paralleling I-205. The 8.3-mile Green Line is expected to serve more than 40,000 riders by 2025 and required $575 million to build over two and a half years. Yet, despite excitement over Portland’s continued investment in rail transit, the Green Line’s route is imperfect, stuck on the side of a freeway and poorly linked to the denser areas adjacent to its route. Its completion illustrates the constraints that funding and history put on local transit advocates and their resulting decision to align a major capital investment along a less-than-appropriate corridor.

In the 1970s, activists in the Portland area put a stop to the Mount Hood Freeway, which would have cut a gash through several neighborhoods in the southeast portions of the city. In response, the state chose to reorient funds towards the first MAX light rail line, which ran from downtown to Gresham. At the same time, highway opponents east Portland and in Clackamas County fought against the proposed north-south I-205. Though they lost their fight, they received in concession space for a transitway along the side and median of the road, completely separated from automobile traffic.

A light rail line from Clackamas to Vancouver, Washington was planned as far back as the early 1980s, but it was repeatedly knocked down by voters before the Green Line was eventually approved for federal New Starts funding in 2007. The new route follows the existing Red and Blue Lines right-of-way between downtown and Gateway Transit Center, where it turns south onto the new I-205 corridor.

When it opened eight years ago yesterday, the Airport-bound Red Line from Gateway Transit Center used the northern portion of the line, and the new Green Line will use the southern section for its eight new stations. By taking advantage of the pre-built highway transitway, Portland saved a bundle of money on property acquisitions and right-of-way preparation. In addition, it was able to construct a line with fast running speeds (just 39 minutes between Clackamas and downtown) because there are no road intersections along the line. Land adjacent to stops had already been cleared for new park-and-ride spaces, which total 2,300 along the route.

But the transitway is the crux of the problem with the Green Line. The highway makes an ideal right-of-way for the purpose of increasing speeds and reducing interference with surrounding neighborhoods, but it is the worst when it comes to spurring transit-oriented development. TOD, after all, should be the primary land use goal of any new public transportation investment, and Portland is likely to get very little of it along the Green Line. That’s because the mere presence of I-205, with its traffic, noise, and pollution, will make development adjacent to it unappealing. Worse, because the transit corridor is located on one of the side of the freeway, people will have to cross the very wide road to get to the other side. These are the same problems Dubai faces with its own just-opened rapid transit line.

Portland’s decision to undertake construction along the freeway was an easy solution to an expensive proposition. After all, much of the Red and Blue Line routes also follow highway right-of-ways, even apart from the airport link aforementioned. But the region’s most emblematic TODs, including the famed Orenco Station, are on the west side of the city, where light rail runs in its own corridor, unencumbered by nearby roads. This should have been the example to follow.

Yet the need to reduce construction costs and the fact that the transitway already existed made it nearly impossible for transit agency TriMet to select a different routing before engineering began in 2005. That said, there was a promising alternative just a half a mile west of I-205: Southeast 82nd Avenue, which has a very wide right-of-way for an urban street and hundreds of commercial outfits bordering it. A priori, it would have been the best corridor to choose because of its potential to spur renewal in the communities alongside it; Portland’s planned Powell Boulevard line does have the potential to do as much, but the I-205 project does not. It is ironic, then, that as far back as 2005, Clackamas County envisioned the Green Line as a way redevelop SE 82nd Avenue — so why not build the light rail line directly on it rather than half a mile away?

Perhaps TriMet planners looked to the Interstate MAX Yellow Line and saw something less than ideal: though the line runs in the median of an urban boulevard, it has not spurred much reinvestment, and though perhaps it is no worse looking than a typical six-lane road, the rebuilt Interstate Boulevard is not aesthetically pleasing either. For all the acclaim planners give the city for its light rail, Portland has yet to design a light rail project whose construction can truly beautify the surrounding areas, a la Tramway Line 3 in Paris. The appeal of an 82nd Avenue route was probably diminished as a result of that precedent.

It is indicative of the way users will use the service that companies near the route are already planning vanpools to carry their workers from stations to business locations, rather than encouraging them to make the walk. The large number of parking locations along the line similarly suggests that this will be a route geared to the driver, rather than to the pedestrian. That’s a pity, because it will mean ultimately lower ridership than what could have been attracted with a project geared to induce dense, urban-level growth. The Green Line will encourage people in the surrounding neighborhoods to choose transit for downtown- or airport-oriented commutes, but not much else, as demonstrated by TriMet itself in its decision to run trains only every 30 minutes after 6 pm.

The project’s major positive benefits in terms of land use will come at the region’s core, where the Transit Mall has been rebuilt for $220 million, allowing for a doubling of dowotnw light rail capacity and direct access to the largest destination in the TriMet service area, Portland State University. The Transit Mall is a series of bus and train-only corridors running roughly north-south on 5th and 6th Avenues downtown, complementing the Red and Blue light rail lines that run roughly east-west on Yamhill and Morrison Streets. Yellow Line trains began running in the Transit Mall on August 30th. Unlike along the I-205 segment, light rail in the Mall will increase the density and transit-oriented nature of the inner city core, which is also to benefit from a major streetcar expansion in the coming years.

Image above: MAX Green Line map, from TriMet