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March 31, 2006

Surface With A Smile?

I wouldn't call it momentum, exactly, but there seems to have been a bit of movement on the idea of replacing Seattle's Alaskan Way Viaduct with a surface boulevard -- a modestly-priced alternative to an aerial rebuild or tunnel. Now, just to be clear, I'm still not convinced that this is an ideal solution. Transportation is complicated, and while other US cities that have removed downtown highways (San Francisco, Milwaukee, and Portland) have never suffered the gridlock that skeptics predicted, the unique layout of Seattle's traffic corridors, industrial areas, and job centers might mean that losing the Viaduct's capacity would create nightmare rush hours for people working (and living) downtown.

Except there's this:  the current plans for the tunnel and aerial rebuild already assume that the city can make do without the Viaduct for three to four years.  That's how long it will take between the moment the existing structure is closed for demolition, and the new one is open for traffic.

Now, I've heard plenty of people argue that traffic will come to a standstill if the Viaduct is replaced by a surface boulevard.  But I've never heard anyone from the city or state admit that their prefered options will do the exact same thing, for at least three years.

So either: a) transportation officials aren't being up-front about this -- and the replacement options have a hidden downside that nobody's talking about publicly; or b) they don't think it's really all that much of a problem, and that they'll cobble together some combination of transit incentives and surface street improvements that will keep traffic flowing.  And if it's the latter, then, goodness gracious, if it can work for 3 years, then why not 10, or 20, or longer?

More to the point, it seems to me that there's pretty good reason to believe that downtown traffic won't have to come to a halt if the Viaduct is closed. 

The official figures say that the Viaduct carries 105,000 trips per day.  But during much of the day the Viaduct is lightly travelled, and there's usually extra capacity on surface streets and I-5. 

The real problems might come during rush hour, when just about every traffic conduit in downtown is full.  But in reality, not that much traffic actually travels on the Viaduct during rush hour.  With only 2 lanes, the Battery Street Tunnel carries at most 10,000 vehicles into downtown during a typical morning rush hour, and 10,000 northwards at the end of the day.  (This is assuming 2.5 hours of rush hour, and a generous 2,000 cars per lane per hour.)  So that means -- from the North anyway -- that the transportation system needs to deal with about 10,000 round trips that would no longer be able to go on the Viaduct.  (I haven't thought things through, but I bet it's a similar number of round trips from the south.)

That's still a lot of trips, but it seems a lot more manageable than the official figure of 105,000.  And there are lots of options to keep people moving.  A new boulevard could handle some of the car and truck trips. Sound Transit may take some pressure off I-5 and other surface streets once it opens.  Improved bus service -- more buses combined with priority timing for buses at traffic lights -- could carry many of the commuters.  Tweaks to the street grid could help keep traffic flowing a bit better.  Some people will simply opt to take their trips at different times of the day, or even forego them.  (Even during rush hour, only a minority of trips are direct trips from work to home.)

Those are just the conventional options.  One unconventional solution--or unconventional in the US at any rate--would be to try what Stockholm and London have already done:  charged drivers to enter downtown. Both congestion pricing schemes have been more more successful than critics might have predicted:  congestion has gone down enough that many commuters believe the tradeoff is worth it.

But the thing to remember is this: unless the city decides to leave the Viaduct as it is (or to retrofit it as some have suggested) this isn't really an optional exercise. The city is going to have to do some combination of these things, and people are going to have to adjust. 

The only question, then, is whether the residents of greater Seattle should spend a few extra billion dollars to fix a problem they've already solved.

Posted by ClarkWD | Permalink


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Great post. I agree that, in some sense, the 4-year construction period will do the work of "solving" the problem. But don't we have to look further down the road (so to speak) than 3-4 years?

Yes, it's only 105,000 trips per day now, but how many in 2030? Here's WSDOT's official memo on the subject:


According to this doc:
- viaduct traffic will grow to 137K trips/day by 2030
- no viaduct will put an additional 24K-33K cars on I-5
- I-5 demand will grow by 70K trips by 2030 even with the viaduct


That said, it does make a compelling case for rapid transit. The $2B we save in not building the tunnel, plus, oh, say... $1.5B we could hypothetically collect with a citywide MVET, would combine to build one snazzy-looking transit system. :)

That's my dream solution - the whole package:
- green line (monorail, light rail, whatever) from downtown to Ballard
- surface street replacement for the Viaduct
- SODO-West Seattle Light rail spur line

I bet we could do all that for what for what it's going to cost to build the tunnel PLUS what we were about to spend on the Monorail. And you'd mitigate most -- if not all -- the capacity of the viaduct.

Posted by: Frank | Mar 31, 2006 5:13:43 PM

"...three to four years. That's how long it will take between the moment the existing structure is closed for demolition, and the new one is open for traffic."

Are you sure it's only 3 - 4 years?
The entire construction time-frame is given as 7-10 years.(Or even more. I have read up to 12 years for some options. And it seems to vary every time I read a press report.) And as you say, the Viaduct will be closed at the start of construction, we are told. So it may be much longer, in fact. The numbers are confusing.

Posted by: David Sucher | Mar 31, 2006 6:50:39 PM

City of Seattle has a very informative map showing visually where traffic flows are now at

Based on traffic count data.

Posted by: John Niles | Mar 31, 2006 7:04:51 PM

Good question. No, I'm not sure it's only 3-4 years. That's just the most recent, and lowest, figure that I've read. I assume that it's based on the scaled-back "core tunnel" option.

For a much earlier version of the proposal, I remember talk of no closure at all: the new one would be built while the old one was still in service. That got jettisoned for cost reasons. (I hope my memory isn't failing me here -- I don't have time right now to check whether this is accurate.)

Frank -

You're right, we should look at longer-term demand. But the rush hour numbers for Battery Street will still hold true, (unless new technologies let drivers reduce the distance between adjacent cars).


Way cool. Thanks!

Posted by: Clark Williams-Derry | Mar 31, 2006 7:56:12 PM

Hmmm...the monorail would have been complete in 2009. Too bad that went the way of the dodo.

Admittedly, the finances were horrible. But when the state makes you pay for things with essentially a credit card, that's whay you get.

Posted by: Ryan Carson | Mar 31, 2006 8:22:38 PM

Here's reference:


Posted by: David Sucher | Mar 31, 2006 8:23:59 PM

The idea of not rebuilding the viaduct and diverting the money that would be saved into expanding rail and bus service should be seriously explored. While this might require a change in laws on how gas taxes are spent, transportation needs need to be considered as a whole rather than independent parts.

Fuel costs are rising and we need to reduce carbon emission due to the very real problem of green house gas emissions. Discouraging the use of privately owned vehicles should be a priority but as long as we continue to build roads, people are going to drive on them.

To expand the "no-build" concept further, why not tear down the 520 Evergreen Point floating bridge and replace it with mass transit? The bridge is at least as ugly as the Alaskan Way viaduct and is going to be a huge expense to replace.

Posted by: Gary Maxwel | Apr 1, 2006 10:10:12 AM

"... if the Viaduct is replaced by a surface boulevard."

Btw, what is this business of a "surface boulevard?" (The term "boulevard is a nice linguistic sleight-of-hand. It will be a ROAD.)

Has anyone seen a configuraion? I assume that going northwards it climbs up past the Market? From the level of Alaskan Way to the Bell Street Tunnel. With trucks making a steep grade 24 hours a day? And that's an improvement over the Viaduct?

I tell ya, folks. It's a trap. No matter how you turn there is NO good solution and retrofitting the Viaduct will be seen eventually to be the best of a bad lot. We'll moan and groan but that's what we'll end up doing because everything else is even worse.

That's how life works.

Posted by: David Sucher | Apr 2, 2006 8:50:50 AM

As to Gary's point:

You've touched on a fundamental problem with the way our gas tax dollars are used. The state constitution earmarks that gas tax money goes to roads, not into the general fund. Thus, the "this might require a change in laws on how gas taxes are spent" comment means that the state constitution would need to be amended in order to divert any gas tax money to transit. Given that it takes a 2/3 majority in both houses to get that passed, I think we would need to see a statewide campaign focused on decoupling those revenues from those expenditures in order to allow for more flexibility at WSDOT.

However, as we learned with Monorail...this is extremely difficult to do, especially with regional programs. Consequently, transit agencies are always begging for new MVETs or some other scheme, which are now also more difficult to get (thanks Tim Eyman).

Nevertheless, if the time was ever ripe for something like this change, it would seem to be now...or at least soon. I'd like to think that reality has begun to set in, and that legislators might be willing to strike a bargain on this.

Posted by: Ryan Carson | Apr 2, 2006 9:19:59 AM

Here's the reference cite for my last comment:


Artile 2, Section 40 of the State Constitution.

Posted by: Ryan Carson | Apr 2, 2006 9:41:10 AM

I may be mistaken, but I believe the surface boulevard option would essentially take the Bell Street tunnel out of service permananently. The surface boulevard/roadway will essentially be a somewhat enlarged version of Alaska Way, and from the north the Highway 99 expressway will simply end at Denny Way (where it now enters the tunnel).

Posted by: Roy Smith | Apr 2, 2006 8:51:53 PM

The term "boulevard" is not a "linguistic sleight-of-hand" if they actually intend to do a boulevard along the waterfront. A boulevard is a road, of course, but it specifically refers to one that is urban, wide, landscaped, and pedestrian friendly. If that is what we got along the waterfront, that would be awesome.

Posted by: gene | Apr 3, 2006 10:29:11 AM

Hey Everybody,
If you have doubts about what the Transit/Surface alternative would look like, or how well it could work, or how much it will cost, then ask City Council to study it. Remember, the People's Waterfront Coalition and other advocates for this approach have only proposed best estimates based on a blend of some local transportation planners' insights, the experiences of other cities that did this, and the Central City Access Strategy. Before it is ready to be on the ballot, the alternative has to be fleshed out in more detail, and City Council is the body that can and should make this happen. If you want to know more hard facts, tell City Council to study it.

Before we vote, we should all have reasonable answers to these questions for all three choices:
1. How much will it cost each Seattle resident, including a possible 25% cost overrun?
2. What will the waterfront look like when the funded project is complete, from Royal Brougham to Broad Street?
3. What choices will people -- and freight-- have for getting through downtown, and how long is the trip estimated to take?
4. How long is the construction period, and how will the 1200 businesses within a block of the viaduct fare during this period?
5. How does this alternative contribute toward other goals, such as reducing green house gas emissions, making Seattle less car-dependent, making downtown denser and more family friendly, providing access to the Port, and keeping family wage jobs in the city?

Posted by: cary | Apr 3, 2006 12:50:45 PM

1. I know what a boulevard is. I simply don't believe that one is in the offing. But so much of the buzz around is created in fact by sleight-of-hand language and ignoring facts before one, such as that much of Alaskan Way -- certainly north of the aquarium already has many attributes of a boulevard and one of the nice things about Alaskan Way is that for much of the time is fairly quiet, too.

2. The idea of taking the Bell Street tunnel out of existence and distributing that traffic through First through Fifth Avenues is an intriguing one and I am all for studying it, as dubious as I may be that getting rid of the viaduct corridor is wise or politically possible.

In fact If the Mayor and the other people who oppose the PWC plan were really smart they would showering research money on the "tear-down" option -- on the "up-or-out" theory -- because I suspect that a close study of it will reveal its lack of reality. Of course if I am wrong -- so be it.

Posted by: David Sucher | Apr 3, 2006 12:52:51 PM

Re: David's comments.

Are you saying that you think a simple, two-choice ballot (either rebuild, or tear down) would result in a choice not to rebuild?

If so, you might be right. Although, under the current appropriation, the state won't fund that option.

If that's not what you meant, could you explain further?

Posted by: Ryan Carson | Apr 3, 2006 4:25:17 PM

First of all, I see absolutely no purpose for the vote. It strikes me as a useless waste of money. I am against having a vote.

Second, if there is to be a vote, it should include the PWC plan and the Gray/Twelker retrofit plan (or something like the latter.)

Third, I think that tactically, if the powers-that-be refuse to expand the ballot byond the two most expensive options, that might actually work to the benefit of PWC and Gray/Twelker. There are several reasons:
a. The vote is meaningless anyway since it does not authorize indebtedness to pay for improvements;
b. If the PWC & Gray/Twelker plans are missing, such absence will act to deligitimatize the two leading plans; the mayor cannot claimj a clean win because two of the players were absent from the scrimmage;
c. The PWC plan is not ready to go before the public. From what I have heard it is far too vague and with too much "intention"and wishful thinking.

I could go on.

Posted by: David Sucher | Apr 3, 2006 5:41:40 PM