[Editor's note: Full report on this morning's SR 520 press conference coming shortly. Spoiler alert: The proposed transit-oriented, less-obtrusive 520 bridge replacement may be smarter, but it ain't likely.]

Long eclipsed by the controversy over the Alaskan Way Viaduct, the SR-520 floating bridge replacement is finally emerging from under the radar. As well it should, because what has been proposed for SR-520 raises a major question:

Which is dumber, spending billions on a 2-mile underground bypass freeway with no provision for transit, or spending billions on a 3-mile elevated freeway and bridge that adds two travel lanes but doesn't include a dedicated transit corridor?

And "dumb" really is an appropriate word. Because to anyone who's been paying the slightest bit of attention, it is blindingly clear that the future prosperity of our urban areas will depend heavily on how successful we are at reducing our dependence on cars.

This is no longer a fringe belief. Direct evidence can be found in cities all over the world. And even here in Washington, the importance of enabling alternatives to the car has been codified in a state law that calls for a fifty percent reduction in vehicle miles traveled by the year 2050.

To restate: we have a law on the books mandating that in 2050 the average Washingtonian will drive half as much as the average Washingtonian does today.

So how do we get there? It's an immensely complex challenge, no doubt, but one thing's for sure: We're not going to get there by building more roads. The rampant road building of the past half century is precisely what has locked us into land use patterns that require excessive driving for people to simply meet the needs of their daily lives.

And new roads don't just exacerbate car dependence; they also tend to compromise transportation alternatives. For one thing, in a world of shrinking government budgets, every dollar spent on roads is a dollar not available for transit, bike, or pedestrian infrastructure (and if we have laws preventing us from spending our tax dollars wisely, we need to abolish those laws).

But the root problem is that optimizing conditions for the movement of cars is almost always in direct conflict with optimizing pedestrian and biking conditions. And since transit trips begin and end with walking trips, undermining the pedestrian environment also undermines transit use.



The proposed SR-520 interchange at Montlake Blvd is a classic example of this conflict (see image above). Today it is already a nasty and unsafe zone for pedestrians and cyclists, but the new plan—because it adds car capacity—will only make things worse. The priority given to cars cripples the huge opportunity for non-motorized travel between the University of Washington and neighborhoods to the south.

To be fair, the plan does make attempts at mitigating pedestrian impacts by adding freeway lids in several locations (see below for a rendering of the proposed lids near the intersection of I-5 and SR-520). Some of these (like the greenspace on the right in the rendering) would likely be successful, but others (like the one on the left) are disconnected spaces that would probably end up deserted most of the time.



In terms of the primary function of the Option A+ proposal supported by the governor and a legislative work group tasked with coming up with a preferred replacement option, the only defensible end goal appears to be to relocate the traffic bottleneck away from the SR-520 bridge. The plan would deposit an additional 20,000 vehicles per day into the Montlake area and onto I-5—effectively relocating the congestion, since vehicle capacity in Montlake and on I-5 is already tapped out. The situation on the east end of the bridge would be similar. And let's not forget induced demand, which would quickly fill any excess capacity on the SR-520 bridge, unless usage is significantly curtailed through tolling.

An excellent summary of the shortcomings of the Option A+ plan can be found here. And the latest Environmental Impact Statement (EIS) is available here. (One aside on the EIS: on page 7 it states, "Congestion generates pollutants from idling vehicles, which are much less efficient than vehicles operating at higher speeds." The myth that expanding freeways can cut greenhouse gas emissions by reducing congestion is debunked here .

This morning Seattle Mayor Mike McGinn, along with other elected officials, neighborhood activists, and environmental leaders, announced "a consensus view of the future of the SR 520 corridor," that calls for four travel lanes and two dedicated lanes for transit. Three key advantages of that configuration are: 1) That transit would more efficient without competition from cars in a shared HOV lane; 2) that it avoids the future conflict that would inevitably arise over conversion of the two HOV lanes to transit only, and 3) the size of the roadway—as wide as 300 feet in some places—could be reduced because access lanes would not have to serve both transit and cars. (See this Seattle Transit Blog post for a wonky discussion of the gory details.)  Of course, this plan would also provide less car capacity than the six-lane proposal currently favored by the state.

There is no question that the SR-520 bridge is an essential piece of transportation infrastructure that links major population and job centers. But there remains a huge question about how different modes of transportation should be prioritized in such a massively expensive infrastructure investment that will shape our region---for better or for worse---for decades to come. And the increasingly indisputable answer to that question is that we must raise the priority on transit, walking, and cycling.

If we hope to make a transition towards a more balanced, sustainable transportation system, we will have to start making some tough choices in the near term in order to benefit everyone in the long term. If not now, when?