Friday, October 11, 2019

Changes coming to the northbound SR 99 tunnel off-ramp to South Lake Union

By Emily Glad

On Monday morning, Oct. 14, drivers who use the northbound SR 99 tunnel exit to Mercer and Dexter in Seattle will notice something different - flexible pylons that will steer exiting traffic to remain in the single lane exit rather than line up on the shoulder.

Why the change?

The northbound off-ramp is designed for a single lane of traffic. However, during busy times, drivers sometimes create a second lane of traffic by driving on the shoulders of the ramps.
Drivers who use the northbound SR 99 tunnel exit at Mercer and Dexter will find
flexible pylons guiding them to a single lane under tolling equipment.

As we tested tolling equipment in advance of the start of tolling the SR 99 tunnel, we noticed inconsistencies with toll readings at the northbound off-ramp that created the potential to charge vehicles incorrectly. This only happened when drivers created two lanes of traffic. The toll equipment functions properly when the exit remains a single lane.

In an effort to make sure no one is overcharged, pylons will now guide drivers into a single lane exit until vehicles pass underneath the toll reader.

Are the pylons permanent?

The pylons are a temporary fix. This is a complex tolling system, and finding the right solution will take time. Until that happens, we must ensure that our equipment is able to work properly. We are working with our partners at the City of Seattle on a long-term solution.

Plan ahead

Tolling in the tunnel starts November 9. During peak periods, tunnel exits see more volumes, so plan accordingly. It’s always a good idea to follow us on Twitter and download the WSDOT app to stay updated.

1 comment:

Unknown said...

Thank you for adjusting the bus lane on N.99. I can't take the bus. However, adjusting the merge 1,000feet north greatly improved my compute time by almost 10 minutes. It likely improved bus travel times as well. Hope you check the data and see for yourselves. Thanks again (don't screw it up, plerase.)

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