520 HOV Lanes Will Soon Get Better…For a While
Rest of the West project scope and timeline
About a year from now, transit riders and carpoolers traveling between Seattle and the Eastside will notice a big improvement: for the first time in history, State Route 520's HOV lanes will extend all the way from Bellevue to Montlake. If your bus or carpool happens to traverse this segment of road, you'll have a speedier, more reliable commute. It will be glorious.
Unfortunately, about a year later, it will disappear again, and the HOV lanes will be back to where they are today, ending part way across the lake.
Chalk it up to a matter of timing and funding.
The 520 bridge project was designed to be completed in phases, since WSDOT wasn't sure if or when the legislature would kick in the necessary funds. And so, in mid-2017, the West Approach Bridge North (WABN) project will complete, and Westbound traffic will be diverted to the new bridge while the old approach bridge is re-striped for Eastbound traffic. Each approach bridge will carry two general purpose (GP) lanes and one high-occupancy vehicle (HOV) lane.
If more funds hadn't materialized, the project would be wrapping up at that point. But the legislature ponied up, and the $1.6B "Rest of the West," which replaces the old approach bridge as well as the rest of the connection to I-5, including lids at Montlake and Roanoke, will begin construction in 2018. At that time, the old approach bridge will be demolished, and traffic will be diverted onto the WABN in both directions. The WABN will be re-striped to carry two GPs in each direction, thereby ending HOV access all the way to Montlake. That will be the situation for about five years until the Montlake lid and surrounding elements are built.
Curious, I asked WSDOT if they had studied the idea of keeping HOV access all the way to Montlake. Larry Kyle, lead engineer for the project, explained that the northern approach bridge is a bit wider than its southern complement but still too narrow for more than 4 lanes. According to WSDOT's models, traffic delays would be too severe in the Westbound direction if there were only a single GP lane. Bicyclists, fortunately, will have access to the full length of the bridge during virtually the entire construction period.
One other interesting tidbit: some folks were dismayed to learn that the 2nd bascule bridge at Montlake was slated for the very end of the project. Kyle told me that the phasing was based on funds from the legislature, not engineering. Therefore, if the city or another entity were interested in advancing the funds for the second bridge sooner, it could possibly be moved up by a few years.