New traffic concurrency model ignores congestion; city council caves to staff

By Miki Mullor
Deputy Editor

Sammamish drivers hoped for traffic congestion relief when the City Council adopted an emergency building moratorium last year in order to take time to fix the traffic concurrency model.

What they are going to get is a new model that’s worse than the old one and worse traffic.

The new model suggests that traffic in Sammamish has improved between 2014 and 2016 and it is better on Sahalee Way, which is notoriously backed up during the morning rush hour.

Traffic is better and not congested, says the traffic model

The new model suggests traffic at intersections all over the city is better in 2016 than 2014.

But drivers have a different experience. They’re backed up in congestion on Sahalee Way; on 228th; on East Lake Sammamish Parkway; on Issaquah-Pine Lake Road; on Issaquah-Fall City Road. They drive it every weekday. Just ask them.

But the new modeling says it isn’t so.

Despite at first telling the city council the new model could take into account congestion, now consultants say it can’t.

Fundamentally, the new concurrency model says congestion doesn’t exist.

Concurrency requirements

Concurrency is a legal requirement by state law to prohibit new development if it causes a level of service on roads to drop below a locally set standard.  The law allows new development to continue only if roads improvements to bring the level of service to standard will be completed within six years. A key component of “concurrency” is a traffic monitoring and forecast model that can predict the impact of new development on traffic conditions.  

Last year, City Council enacted a moratorium after it was discovered that the city’s concurrency system was rigged to never fail by ignoring congestion.  City staff was directed to develop a new concurrency system that will measure the driver’s experience. While council members favored a system that is based on time to travel (how long it takes to drive through a road segment), staff suggested it would take too long and be too complex to achieve. (King County and Vancouver, WA both have their concurrency based on time to travel)

Instead, staff suggested tweaks to the current system and measure the delay drivers experience at intersections (“Intersection LOS”).  Over the course of the last few months, staff assured council members that the proposed system will measure delays and congestion (“queue”).

The new model can’t handle congestion

Earlier this month, staff revealed the results of the new concurrency system; some council members were stunned to learn that the new model shows as if traffic improved from 2014 to 2016, especially on notoriously congested Sahalee Way.  

In an interview  with The Comment, Cheryl Paston, the Deputy Director of Public Works, admitted the proposed model doesn’t measure congestion and has an inherent limitation: it cannot handle stand-still traffic.  This is contrary to what council members were told over the course of the last seven months.

During the May 15 council meeting, staff confirmed what The Comment reported: the methodology recommended by staff cannot handle congestion.  

Kendra Breiland

Kendra Breiland, Fehr & Peers

When Mayor Christie Malchow pressed hard on the point, Kendra Breiland of Fehr & Peers, the city’s traffic consultant, admitted Sammamish has serious congestion problems on several of its arterials:

“I often come to Sammamish for 9 am meetings, and I’m coming up from 202, so I have  observed those queues, and so I’m painfully aware of what folks are dealing with everyday. I say thank goodness I’m coming into Sammamish and not leaving,” Breiland told the mayor.

But she failed to address the mayor’s question.

“Standing queues are a huge issue here,” Breiland said. “We need to model them, we need to understand them. Now, is that something that is appropriate to put in place for something that is going to be done routinely for development review? That’s not typically where it’s done,” she says, contradicting her promises to council in the last few months that the new concurrency model will account for congestion and will reflect the driver experience.  

However, according to Sammamish Municipal Code, that’s exactly what Concurrency is:

If any road, street or intersection operates below the level of service standard, development may not be approved anywhere within the City until the level of service is achieved, or transportation improvements or strategies to accommodate the impacts of development will be completed within six years.”  (Sammamish Municipal Code, 14A.10.050 (2))

Breiland met in Bellevue on February 28 with STCA, the developer of the 2,200 apartments Town Center project, for “coordination”, as part of Fehr & Peers’ $934,590 contract with the city.

Congestion is for the long term, not for concurrency

Josh Anderson

Josh Anderson

“You are looking long term, you’re trying to figure out how are we going to build our city out so that our citizens have a reliable origin and destination trip,“ said Josh Anderson, a traffic engineer from David Evans Associates. “Concurrency analysis, that is not necessarily, in my opinion, the place to be looking at that long term origin and destination type of conversation.”

This contradicts the council’s policy decision to base the city’s concurrency policy on the driver’s experience.

Anderson is in charge of developing the traffic model that monitors and forecasts traffic conditions.   

When Malchow continued to press on how will the new model handle measuring congestion, consultant Breiland responded that “[the current model] isn’t really able to address that issue.”

Council caves to staff

Council member Tom Hornish moved to move away from what now looks like a flawed model to what the council originally wanted, a time of travel model that accurately measures the driver’s experience.  No one seconded his motion.

The rest of the council members seemed utterly confused and overwhelmed by the technical details and lengthy, confusing responses from staff to questions.  

In a most telling moment, staff showed a slide that suggested that the “VISUM model is 97% accurate.” But when pressed by Council Member Ritchie on what exactly is being claimed as accurate and whether that accuracy pertains to traffic condition on the ground, staff conceded that the 97% is unrelated to the traffic conditions models, for which they are “continually looking at and making sure that things are feeling right,” avoiding giving a clear answer.

Nevertheless, a confused council voted to continue down the path, even when faced with a disingenuous claim of accuracy.

“I am now convinced that the Intersection LOS [current model] doesn’t measure the driver experience as we wanted from the very beginning,” Hornish told The Comment. ” The model doesn’t work for what we wanted it to do.”

At the end, the council voted 5-2 to move forward with the current model, with Malchow and Hornish opposing on grounds that the concurrency model doesn’t measure the driver’s experience, as originally promised by staff.

The Comment has collected clips from council meeting over the course of the last seven months, showing staff promoting their proposed concurrency model as one that will account for congestion only to admit otherwise this week.  

A confused council, facing pressure from the development community and having spent hundreds of thousands of dollars, has now been boxed by staff to accept a concurrency model that ignored traffic congestion and will allow development in Sammamish to continue unchecked, contrary to campaign promise of all new council members.


9 thoughts on “New traffic concurrency model ignores congestion; city council caves to staff

  1. With the appointment of Mr. Mullor as deputy editor and the publication of articles such as this, the Sammamish Comment has lost any pretense to objectivity. Healthy debate is welcome, but this is a fine example of a diseased argument.
    An analogy used by a critic and political opponent to describe British politician and statesman Winston Churchill’s lapses in good political judgement applies to the Sammamish Comment. “he is like a person who for weeks drives his car safely along this road and that road then suddenly drives up on the sidewalk.” Over the years, the Sammamish comment has offered useful observations with sudden detours onto the sidewalk. Now, with Mr. Mullor behind the wheel, I warn readers to stay off the sidewalk. It is safer to walk in the road.

    • John, if I didn’t want debate, I’d block your comments. I’m not and won’t, as long as you don’t engage in personalized insults.

      At the beginning of the year, Paul Stickney contributed three posts outlining his vision. Jason Ritchie provided a view point in favor of the town center and Debbie Breen provided a counter-point. You’ve provided counter-points. You are welcome to submit a full-post counterpoint that remain within Guest Comment rules (, making your arguments and case for lifting the moratorium and supporting either the old concurrency or the new one.

      Muller is “not behind the wheel” in the sense that you suggest he is in charge of Sammamish Comment. I remind you that I supported exempting the Town Center from the moratorium and I still support the Town Center plan as we created it on the Planning Commission. I oppose reopening the plan.

    • Appears you’re contradicting yourself, as you seem to be an advocate for healthy debate, but then present no substantive points to support your assertion that this is a “fine example example of a diseased argument.”
      So, why is it a “diseased argument?”

  2. Seems like the discussion is firmly on traffic modeling and how to do it. Surely Sammamish is not the first city to have explosive growth feeding primarily onto 1 arterial ! What does the Traffic model say happens?

  3. Let’s not get too carried away with the 97% accuracy statement. It looks like a calibration result, not what would normally be called a validation. The result is about traffic count, not delay. The result shows that if you use everything you know about 2016 and adjust one or more parameters, you can do a good job estimating 2016 traffic counts.

  4. Pingback: Emails reveal secret meetings involving Fehr & Peers, the city’s traffic concurrency consultant – Sammamish Comment

  5. Pingback: BREAKING NEWS: New concurrency passes 4:3; new development now in question – Sammamish Comment

  6. Pingback: How the STCA 419 homes development passed concurrency – after failing it for 9 months – Sammamish Comment

  7. Pingback: Gerend lawsuit: both sides claim victory; development moratorium enacted | Sammamish Comment

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