(This post is part of a series.)

As Joel Connelly points out in today’s P-I, there’s no guarantee that I-912—the Washington State initiative that would roll back the most recent hike in state gas taxes—will pass.  That said, repeal of the gas tax looks pretty likely, in no small part because of the surprisingly tepid response from the state’s business community, which had previously been outspoken in its support for higher gas taxes and transportation spending.

Come November, if the new gas taxes are repealed, the $2 billion in state money currently slated for Seattle’s Alaskan Way Viaduct will simply evaporate.  And as Mayor Nickels has pointed out, without that money there’s essentially no chance that the Viaduct will be rebuilt:

If Seattle doesn’t get the $2 billion approved by the Washington Legislature to help replace the Alaskan Way Viaduct, the city will tear down the deteriorating elevated highway anyway because it is unsafe, said Mayor Greg Nickels.

So it’s perhaps a good time to point out what just happened in San Francisco:  the city just opened a new 6-lane boulevard that—get this—replaced an elevated urban highway.  This is the second time the city has replaced an elevated freeway with a boulevard.  The first was the waterfront Embarcadero Freeway, which was torn down after it was damaged by the Loma Prieta earthquake in 1989.  The city put up a waterfront boulevard in place of the highway—a move that, according to most observers, revitalized a waterfront formerly depressed by the blight of a freeway.  And city residents liked the results enough that they decided to do the same thing to a stretch of the Central Freeway smack in the middle of downtown.

Obviously, the Alaskan Way Viaduct plays a different role in Seattle’s transportation system than the Embarcadero and Central freeways did in San Francisco’s.  But that city’s highway removals do serve as important reminders that, no, a big-city’s transportation system doesn’t necessarily grind to a halt when you put the budget for downtown highways on a strict diet.