So, you might have heard that a couple lanes of northbound
Interstate 5 were closed last week. Hysterical media predictions of
“nightmare” traffic failed to come true. Lists of “survival tips” for
dealing with hellish commutes failed to be necessary. Even an entire
blog (the Seattle Times‘ The Clog) devoted to “the Closure”
couldn’t make the predicted traffic clusterfuck materialize. For nearly
two weeks, half of I-5 has been closed down—and traffic has, as
if by a miracle, actually gotten better.
Collective panic alone can’t explain the startling statistic that
graced front pages last week: Of 120,000 cars that normally use
northbound I-5 daily, half simply went away. Their drivers took
alternate routes, rode transit, worked from home, or didn’t take
unnecessary trips. In other words, they adapted to changed
circumstances.
Well, duh. That’s what people do—in San Francisco (when the
Embarcadero closed in 1989); in Milwaukee (where the Park East Freeway
came down in 2003); and in Portland (where the removal of Harbor Drive
in 1974 made it the first city to actually take out an existing
freeway). And it’s exactly what The Stranger has long said
will happen here if the Alaskan Way Viaduct is closed and replaced with
a modest surface alternative that includes investments in transit and
fixes to the surface street grid downtown.
Traffic models rarely provide accurate predictions of human
behavior—in large part, because they assume humans can’t adapt to
changed circumstances. In the case of I-5, planners’ models predicted
that the freeway would be gridlocked well into Seattle’s southern
suburbs; that every I-5 detour would be similarly congested; and that
nightmare traffic would last all day, eliminating the usual midday
lull. State transportation planners also predicted that if half of
northbound I-5 commuters altered their commute patterns, the congestion
would be the equivalent of a regular weekday rush hour. None of those
predictions—none of them—came true. Traffic got a
little worse on the second day of the closure, as some commuters tried
to take advantage of the open highway, but by the second week, traffic
had leveled out to its previous level.
The I-5 experience blows a hole in the gospel of endless road
expansion. You can’t argue that closing the viaduct would lead to
disaster and then ignore the fact that eliminating half the lanes on a
major freeway through Seattle actually made traffic better.
And that’s without any additional transit service from Metro, the main
transit provider in the region. (Sound Transit stepped up service a
bit, and still found itself with over-capacity Sounder trains.) Imagine
how much smoother the commute on I-5 could have been with expanded
transit to take another 20,000 or 30,000 cars off the road. 