We tend to think of traffic as an immutable — that there’s literally nothing we can do in our day-to-day lives to drive less.

But Seattle’s continued and mostly unexpected free-flowing traffic — in the midst of a major construction project that some feared would trigger a morass of congestion throughout Puget Sound — shows that this is simply false. Far from being rigid and incompressible, traffic and travel patterns are surprisingly fluid. Seattle’s experience demonstrates that, when drivers are given good travel choices and the right kinds of information and incentives, they can get out of their cars. And in Seattle’s case, when lots of people got out of their cars, it made getting to work a relative breeze.

Here’s the deal: earlier this week, two lanes of I-5 — the busiest highway in the state — were closed for major maintenance. Transportation planners expected a quagmire; the media predicted "19 days of pain"; and for weeks, the only water-cooler discussion that mattered was strategies for dealing with "The Big Clog."

But the I-5 closure hype was a bit like the Y2K bug — everyone was worried for months, but the day of the so-called catastrophe was a complete non-event. Commuters found alternate ways to get to work. Some drivers got out of their cars, switching to buses, commuter trains, and water taxis. Others stayed off the roads entirely, by telecommuting from home or from temporary workstations set up by far-sighted employers. The end result: traffic volumes plummeted. So despite the reduced highway capacity, traffic’s been better — freer flowing and way more pleasant — than it’s been in years. And Seattle’s commuters proved that they were wilier and more flexible than anyone gave them credit for.

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Of course, this P-I editorial, by the redoubtable Cary Moon and Kamala Rao, makes the point better than I ever could. So I’ll just shut up now and recommend that you read it.