Make Sound Transit Demonstrate I-90 Bridge Capacity

(I wrote this in response to Bellevue City Council 4/14/17 email, *New look for I-90: Striping work to add HOV lanes across Lake  Washington begins April 21*)

Make Sound Transit Demonstrate I-90 Bridge Capacity

With two-and-a-half years work complete the WSDOT and Sound Transit are planning to spend three “dry” weekends restriping the I-90 Bridge outer roadways to add an HOV lane in each direction.  However, they don’t plan to open the HOV lanes until June 3 to coincide with their permanent closure of the bridge center roadway to begin construction of their East Link light rail extension.

This latest delay in allowing commuters to use the outer roadway HOV lanes typifies Sound Transit’s planning for the added lanes.  It’s something they could have done more than ten years ago, benefitting cross-lake commuters from both sides of the lake, but especially reverse commuters.    One “possible” reason was the added outer roadway lanes could have been used for non-transit HOV and inbound and outbound BRT initiated on the center roadway ending any hopes of implementing light rail.   That option ended some time ago.

The recent delay is even more insidious.   They want to avoid any demonstration the added HOV lanes provide the capacity needed to accommodate all the cross-lake vehicles during light rail construction and when East Link begins operation.  The WSDOT/Sound Transit convinced a federal judge in the “Freeman” suit they had documentation showing the added lane configuration (R-8A) could accommodate all cross-lake vehicles.  Yet the Sept 2004 FHWA Record of Decision they cited required maintaining both center roadway lanes for vehicles.

It’s not clear whether the FHWA has “reconsidered” their position on outer roadway capacity.  Even if the have, common sense demands Sound Transit delay “permanently closing” the center roadway until they demonstrate outer roadways can accommodate both current vehicle traffic but future traffic as well.   Especially since East Link operation will likely increase not decrease cross-lake vehicle traffic. 

The problem being the Downtown Seattle Transit Tunnel (DSTT) limits East Link to one 4-car train every 8 minutes.  It doesn’t have the capacity to accommodate the 63 buses currently using I-90 during the peak hour in the peak direction as well as those getting on light rail at earlier stations and Mercer Island commuters.   The hassle of trying to transfer to overcrowded light rail cars will persuade many to “drive” rather than “ride” more than offsetting any reduction in bridge bus traffic.  Even worse, those former transit riders will add to the far worse congestion on bridge GP lanes.

It’s also "unlikely" East Link capacity will ever increase.  Sound Transit will spend $3.6 billion disrupting those who live or commute along the route into Bellevue during light rail construction to create light rail the vast majority of I-90 commuters will never have access to.   The least they could do is demonstrate they and future commuters won’t face gridlock on outer roadways.  

The WSDOT refusal to require the demonstration "suggests" they’re more interested in the increased revenue from SR 520 tolls and lucrative HOT fees needed to maintain 45 mph on HOV lanes because of the I-90 congestion than in easing the congestion.  Thus it’s up to the Seattle Times to urge the demonstration, the east side city councils to sue for the demonstration, or the House and Senate Transportation Committee to require the demonstration. 

Failure  to do so will likely result this summer in congestion that is only a precursor to that when East Link begins operation and any future growth in cross lake commuting.