The I-405 Debacle Continues,

A Dec 25, 2017 Seattle Times article “I-405 express toll lanes between Renton and Bellevue are on their way” included the following:

In 2019, work crews on Interstate 405 will start building a new lane in each direction between Renton and Bellevue, as part of a series of changes that aim to improve traffic flow on what officials call Washington’s worst corridor for congestion.

Then, five years later, the Washington Department of Transportation (WSDOT) will open the new lanes, and an existing one each way, to traffic as express toll lanes, extending the interstate’s current tolling system between Lynnwood and Bellevue that opened in 2015.

WSDOT will spend $1.22 billion on the upcoming project, funded by the statewide gas-tax increase approved by the Legislature in 2015.

Clearly nearly two years ago money had been allocated to begin implementing the 2 HOT lanes on I-405 between Renton and Bellevue. WSDOT said the upcoming I-405 project would cut driving time in the general-purpose lanes by about 30 percent

Yet nearly 18 months later a May 9^th 2019 Seattle Times editorial proclaimed, “the Legislature wisely addressed Eastside commuters’ daily I-405 logjam through a widening project”.  It’s not clear what the legislature did since funding was already available.

Apparently the WSDOT still didn’t get the message since 6 months later nothing has been done and congestion on “Washington’s worst corridor” continues to increase.  And the “current tolling system between Lynnwood and Bellevue that opened in 2015.” hasn’t reduced travel times.  

The WSDOT Nov 18^th, 7:45 am travel time for the 16.2 miles was 54 minutes on GP lanes and 44 minutes on HOT lanes.  Clearly 2 HOT lanes between Bothell and Bellevue hasn’t reduced GP travel times. Those willing to pay the tolls saved ten minutes.  However their average velocity over the route was only 22 mph, while better than the 18 mph GP velocity, was far short of the 45 mph the WSDOT had promised for HOT velocities for 90% of the peak commute. 

The “standard” premise for HOT is the fees can be raised on an HOV lane to limit traffic to what’s required to meet desired velocity, typically limiting traffic to 2000 vehicles per hour (vph) assures 45 mph.  The WSDOT apparently believes tolling increases that capacity, choosing to do so on two HOT lanes. That limits GP traffic to three lanes, increasing congestion to where more than 2000 vph were willing to pay the tolls on the two lanes.  Yet the GP lane traffic still slowed to 18 mph and HOT lane velocity to 22 mph.

Clearly increasing HOT fees on one HOV lane to limit traffic and allowing GP traffic on the second HOV lane to reduce GP congestion would raise both velocities.   Assuring 45 mph on HOV lane would also make BRT routes more attractive if Sound Transit would ever agree to add the 100 bus routes an hour needed to reduce congestion. 

Instead the WSDOT is more interested in increasing toll revenue than in reducing travel times.  Despite the fact the toll revenue only covers the system operating costs and does nothing to recoup the millions spent to implement it.  Until they limit HOT to one lane future traffic growth is only going to exacerbate the problem between Lynnwood and Bellevue.  

The “widening project” heralded by the May 9^th editorial does nothing to address the Lynnwood to Bellevue congestion, instead extending the two HOT lanes from Bellevue to Renton.    The Nov 18^th, 7:45 am travel times for the 10.9 miles were 47 minutes on GP lane and 19 minutes on HOV lane.  Yet rather than using new lane to reduce GP congestion they add two-person carpoolers to GP traffic.

The resulting congestion will again result in more than 2000 vph willing to pay the tolls on each of the two HOT lanes.  Limiting GP lanes to two of four lanes will likely result in even slower velocities on both GP and HOT lanes between Renton and Bellevue.  Again the obvious solution is to implement HOT on one HOV lane with fees raised to assure 45 mph and allow GP to use additional lane.  Again enabling the expanded BRT routes needed to reduce congestion.

The I-405 debacle will continue until the WSDOT recognizes that reality.