Work of mischief-makers near the Route 520 Bridge   (via QFox13)

At the start of the year I wrote about how the re-imposition of tolls on the Route 520 Bridge, one of the two spans going east from Seattle across Lake Washington to the suburbs of Bellevue and Microsoft-land, is a terrific laboratory for behavioral economists. Those are the folks who study how psychology affects personal spending decisions, or, to put it a little less kindly, why people make so many stupid mistakes when it comes to their money.

In the case of Seattle, the issue concerning the bridge is how many  motorists would decide to avoid what is now a minimum one-way peak-hour toll of $3.59 (which sounds more like a gas gallon price) by driving miles out of their way to take the free Interstate 90 bridge or go around one end of the narrow 22-mile-long lake. Including the extra gas, vehicle depreciation and especially the value of one’s additional travel time, the “free” routes cost several times more.

Nevertheless, from what I, New To Seattle, can tell, a large number of drivers have fled the Route 520 bridge, which is formally named the Governor Albert D. Rosellini Bridge-Evergreen Point. These motorists seem to focus solely on the tolls, ignoring all the other costs, although some may be deriving pleasure from simply sticking it to the state no matter what the personal expense (that’s the psychology part of behavioral economics). The extra driving has helped make things on the roads even worse in Seattle. A new study just ranked the city the country’s fourth most traffic congested big city–up from 12th last year, before the tolls.

But hey, behavioral economists, don’t leave town yet! The state is whipping up yet another petri dish for your professional scrutiny.

Route of the Route 99 tunnel

Along the downtown Seattle waterfront, work has begun on taking down the free Alaskan Way Viaduct, the elevated roadway that carries a portion of north-south Route 99 through town, and replacing it with a $3.2 billion tunnel for which tolls would be charged. (The justification for the rather expensive project is that the 59-year-old Viaduct is vulnerable in an earthquake.) According to The Seattle Times, a new study by the Washington State Department of Transportation figures that with an average one-way toll of $3.00, as many of 42% of the vehicles that would take a free tunnel at peak times will stay on city streets.

My guess is that the diversion could even be more. That’s because unlike the three free east-west options to get from Seattle to the other side of Lake Washington, there are a dozen or more free north-south routes–city streets, essentially but also Interstate 5–that would do the trick, most of which add nil mileage to the trip.

That still leaves the issue of added time, especially since the free streets traverse always congested Downtown (where Amazon.com is building like crazy) plus nearby crowded neighborhoods like Capitol Hill and First Hill and the area around the sports stadiums. But, if the Route 520 Bridge is any judge, passing-through motorists won’t much take that into account. People living in those neighborhoods, however, might have a different view.

State planners are trying to figure out the sweet spot: the toll schedule that will produce the most revenue and provide the least excuse for Route 99 motorists to bail. Among the options under consideration: tolls that vary by time of day and direction of travel. Given all the travel alternatives, low tolls all the time would seem to be an extremely promising strategy. It certainly works for Walmart. But the state says it needs to generate something like $200 million in toll revenue over the years after the tunnel’s expected opening in 2015.

Here’s hoping the behavioral economists keep a close eye on this one. I recommend they also regularly file freedom of information act requests with the state transportation department to get any secret work papers on the great thought processes taking place. If the end result in three years is a perpetual daily traffic gridlock across the narrow center of hourglass-shaped Seattle, my guess is that the documentation identifying exactly who is to blame will have gone the way of the Seattle Post-Intelligencer‘s print edition.

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