The Evolution of Seattle's 520 Bridge

Big changes are under way on the 520 bridge, the longest floating bridge on Earth.

Just when you thought cross-lake commuting couldn’t get any more fun, tolling on the S.R. 520 bridge went into effect. Now, crossing the floating bridge can set you back as much as $5 one way, depending on the time of day and whether you have a prepaid “Good to Go!” pass affixed to your windshield.

Tolls collected will pay for construction of the new six-lane 520 bridge under way right now; currently, 33 enormous concrete pontoons are being built in Aberdeen to be floated here. The bridge should be finished in 2014; tolling is expected to continue at least until the 30- and 40-year bonds are paid off—in 2056. To save money on tolls, ride the bus, share the ride (, or check out a pair of new apps: and


The bridge as it exists today, with four general-purpose lanes



The updated bridge, with four general-purpose lanes, two carpool lanes and a pedestrian and bike path



The new 520 can be retrofitted with additional pontoons to bear the weight of light rail at a future date


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