This morning, I’m saddened to see King County Councilmember Larry Phillips drawn in by backwards arguments for a Viaduct tunnel. His heart seems to be in the right place, but his conclusions do not follow.
Paradoxically, the Viaduct is actually bad for mobility. Because it allows people to entirely bypass downtown, it encourages spread out development, and results in commutes that go from a neighborhood on one side of the city to a neighborhood on the other. This has two impacts.
First, it encourages businesses to sprawl, instead of staying in the accessible downtown core. This has always been the problem with highways – they break down the efficient hub and spoke structure of human settlement. When someone can take a trip from Ballard to West Seattle for work, that’s great for them, but then someone in Ravenna or Mount Baker can’t get to that job as easily as if it were in the core. Net mobility is lower. Multiply by a hundred thousand, and you create congested arterials all over town, as we have today.
Second, these through trips the Viaduct generates are generally not replaceable with transit. Again, the only way it’s cost effective to build transit is in a hub and spoke layout, and for most of these trips, that means an uncompetitive downtown transfer.
Right now, Phillips says, 70 percent of traffic on the Viaduct is pass-through. In the next sentence, he refers to ‘that traffic’ being pushed through the downtown core by the surface-transit option. He’s partly right – when the Viaduct is brought down, whether for good or for replacement, most of those trips will go onto downtown streets and I-5.
But ‘that traffic’ will change dramatically.
Even on the first day of closure, many ‘soft’ trips will switch to transit. That’s not just the viaduct trips – when viaduct users switch to other corridors, a lot of soft trips on I-5 will also switch to transit, as will many that were previously taken on surface streets. I’ve pointed this out before – over months and years (and even a construction closure will be years long), leases expire and jobs are gained and lost, so many of those through trips will disappear through attrition when they’re no longer effectively subsidized by the free trip through downtown.
The benefits of not rebuilding a bypass are many. Average commute mileage decreases, reducing emissions. New non-through trips are more often replaced with transit. Every time a business chooses to locate downtown instead of in a neighborhood or suburb, mobility increases for the huge number of people who have transit access pointing to the urban core.
And I think Larry Phillips can appreciate that. With downtown office space dropping in price due to the recession, but several more downtown office towers under construction, we have a lot of space available and getting cheaper. Remove a subsidy to sprawl, and we take advantage of the recession to concentrate development downtown. That’s smart growth.