Make WSDOT/Sound Transit Demonstrate I-90 Vehicle Capacity

The Seattle Times June 2^nd B-1 page article “Mercer Island to get $10M in I-90 dispute” provides a glimmer of hope for I-90 commuters.  It’s not in the promises of “additional parking and safety”.   Islanders don’t need additional parking.  They only need Sound Transit to prevent “off-island” commuters from using existing parking by allowing them to pay a nominal fee to reserve a parking stall at their existing P&R.  Yet Sound Transit refuses to do so. 

It’s surely not the pontifications of Redmond Mayor John Marchione, “this was a cooperative, collaborative.”  Sound Transit has been anything but cooperative choosing to countersue instead.  Mercer Island Mayor Bruce Bassett’s comment “the agreement advances the mobility needs of our residents” exemplifies his refusal to recognize that East Link will essentially end Islander’s easy access to Seattle.  Not only will they lose access to center roadway, their access to outer roadway will be severely “throttled” on the last onramps to the congested outer roadway. 

When East Link begins operation its schedule will only provide one 4-car train every 8 minutes.  Again, their last-with-access to East Link means the trains will likely be full before they ever reach the station, at least during peak commute.  Sound Transit plans to transfer hundreds of bus riders to East Link at their station will surely exacerbate the problem.   It’s absurd to think the $10M for parking will “advance the mobility needs of our residents” with Islanders and hundreds of bus transferees waiting for access to light rail at their station

The “glimmer of hope” is the statement “Sound Transit is scheduled to take custody of the center express lanes on June 14th to begin light rail construction”.   “Hopefully” the reason for the delay is to determine whether the HOV lanes added to the outer roadways provide the increased capacity needed to accommodate all the cross-lake vehicles.   Not only must the modified outer roadways accommodate all current vehicles, they must have the capacity to accommodate future cross-lake demand.

Part of that future cross-lake demand will be the fact that East Link operation will increase, not decrease, outer roadway traffic.  The problem being East Link's limited capacity can only replace about 50 buses an hour during peak commute.  Removing 50 buses from the likely 2000 vehicles an hour on the HOV lane will have a minuscule effect on congestion.   

More important, the congestion is on the GP lanes not the HOV lanes.  Even that reduction will be offset because large numbers of former bus riders will chose to “drive” rather than “ride” to avoid the hassle of transferring to and from East Link.  Those numbers will far exceed the 50 buses, adding even more vehicles to the already likely congestion GP lanes.  Added to the former transit riders will be future cross-lake transit demand.  East Link can't accommodate any of what Sound Transit’s East Link EIS said would double in the next 30 years. Thus, any assessment of the I-90 Bridge outer roadway ability to accommodate cross-lake traffic needs to consider future requirements. 

It’s not clear whether the delay was in response to WSDOT concerns or an FHWA requirement.  The WSDOT, in their 2007 commitments to Mercer Island, was already planning to  implement HOT on HOV lanes, presumably in response to the “need” to maintain 45 mph.  They "may" have been anticipating heavy congestion there as well as increased toll revenue on SR520 from those avoiding I-90 congestion.  Thus their requirements may be less “stringent” than the FHWA’s.  Particularly since the FHWA in a 2004 ROD concluded the center roadway lanes were still needed for vehicles even with the outer roadway's added HOV (R-8A) lanes. 

Both the WSDOT and FHWA need to recognize that outer roadway congestion during the 10-day demonstration period is only going to increase.  That East Link capacity is never going to increase.   Any added light rail riders from Bellevue, Bel-Red, or Redmond will simply subtract from I-90 commuters accessing at the two P&R stations; at least during peak commute. 

The “glimmer of hope” for the entire eastside is the result will confirm the FHWA’s 2004 conclusion that the center roadway is still needed for future cross-lake vehicles; effectively ending the East Link debacle.

Addendum: I noticed the Tuesday 7:15 Issaquah to Seattle travel times had increased from 27 to 37 minutes
2nd Addendum:  Wednesday's 7:30 AM Issaquah to Seattle had increased from 31 to  45 minutes
3rd Addendum:  Thursday 8:10 AM Issaquah to Seattle increased from 30 to 46 minutes