One of the limiting factors in the public debate (if you can call it such) is a certain misunderstanding about how traffic works. When people are told that 110,000 cars per day use the current viaduct, they tend to make a very natural assumption: that if the viaduct were removed then 110,000 cars per day would be forced to use city streets to get around, resulting in massive gridlock. The thing is, this just isn’t true.
For starters, not every trip is equal. Some people use the viaduct just because they can, or because it’s a pretty drive, and if the viaduct were removed many of those trips would just disappear or be combined with other trips. Another critical issue is the tolling of SR 99. In order to pay for the tunnel the State is planning on introducing a toll of about $1 per trip. Even the State’s traffic modeling predicts that at that rate, approximately 40,000 trips per day disappear. That means that much of the demand will be removed because of the financing required to pay for the tunnel; which we only “need” in the first place due to the supposedly inflexible demand!
Another natural misconception involves the value of freeways versus city streets for moving traffic. Think of where the worst traffic in town is. Do you have it in your head? Is it 45th at I-5? 5th Avenue Downtown at Cherry or Spring or Union or Stewart? The Mercer Mess? Do you see the pattern? The worst traffic is always at the interface points between the freeway and the street grid. Turns out that freeways are great for going long distances through farmland, but really bad at moving people efficiently through a dense city. City streets are much better at moving cars around town efficiently, but they get overwhelmed by the presence of huge lines of cars trying to enter or exit the freeway, creating problems across the grid.
On that note, imagine the Mercer Mess at rush hour. Did you know that the tunnel’s north portal is right at Mercer and Aurora? Can you imagine what that volume of traffic will do when you pump it directly into the chaos of Mercer? This is the city’s solution to our traffic problem?
Here’s another fun fact: about 60% of the traffic on the viaduct either starts or ends Downtown. Did you also know that there are no Downtown exits to the tunnel? So out of those 110,000 cars per day, 66,000 of them are headed downtown, and these cars will have to use city streets anyway. That leaves about 44,000 through trips for the tunnel. Let’s say 10,000 of them won’t use the tunnel because of the toll, and now you’re down to 30-35,000 trips through the tunnel, plus however many thousand people who otherwise wouldn’t have been driving who decide to make a trip. Is that really worth the investment? When light rail opens, it is expected to carry 43,000 passengers per day. Wouldn’t it be better to spend our money on fixing the I-5 bottleneck, improving the surface streets and building a high-capacity mass transit system for the Ballard to West Seattle corridor?
So here’s the big issue. It isn’t like Seattle would be the first city in the history of creation to remove a freeway. This has been done in dozens of cities around the world, and the effect is always the same: when you remove a freeway, people either figure out how to get where they’re going in some other way, or they just stop making the trips altogether. I know that everyone is an expert on their own commute, and nobody can imagine doing things any other way than the way they’re currently doing them, but consider this: most Seattleites either change jobs or move house once every three years. If something big changes, like the viaduct comes down, then our live/work patterns will start to change. When San Francisco took down the Embarcadero Freeway and the Central Viaduct (with the help of the Loma Prieta earthquake) nearly everyone was expecting major traffic snarls. And they did have bad traffic, for about a month. And then people figured it out. Today, you can’t find anyone who thinks removing those freeways was a bad idea, and it would be political suicide to suggest building them anew.
It’s the same thing in Seattle. If there weren’t already a freeway on the waterfront, no one in his or her right mind would consider building one. Are Seattle’s residents any less intelligent than those of San Francisco, or Portland, or Buffalo, or Milwaukee, or Seoul, or Paris, or any of the other dozens of major cities who have experienced exactly this issue? Do we really believe that we cannot adapt?
Of course we can. We can live without this. We can have a beautiful waterfront without burying a two-mile tailpipe under the city. At a time when we’re laying off teachers and kicking poor people off the state health care rolls, is it really worth $2500 per Seattleite to bury a freeway, just to save yourself five minutes on a trip between West Seattle and Shoreline?