I wrote recently about the proposed tolls on the SR 520 floating bridge in Seattle. The bridge is to be replaced, with tolls imposed on the current bridge to help fund the work.
|SR520 in blue will be tolled. I90 beneath it will not be tolled|
Now the Seattle Times reports on the study compiled to prepare construction bonds for the project which claims that traffic will drop from around 100,000 vehicles a day to around 52,000. The reduction is due to some suppressed trips, mode shift to public transport and diversion to Interstate route 90. So the tolling will effectively deal to congestion, with traffic levels not returning to pre-toll levels until 2032. The tolls will pay back a US$1 billion bond (total cost is US$4.65 billion for the bridge) and generate more than enough revenue to support it.
Curiously, the report also states that if equivalent tolls are placed on the I-90, then toll revenues on SR 520 increase by 38% - because the diversionary route is no longer more attractive. State Treasurer Jim McIntire is confident that toll revenue will support the proposed bonds. It's worth also remembering that the proposed tolls in include congestion pricing at peak times, a trend that is appearing more regularly on new toll facilities in the US, and a very welcome one to aid sustainable use of the infrastructure and to maximise revenues.