SR 9 & SR 204 Intersection, Lake Stevens, Washington.

Started by ErmineNotyours, February 07, 2019, 10:16:41 PM

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ErmineNotyours

Heard this report on the radio today: Lake Stevens Highway 9 project changes again

QuoteThis intersection at Highway 204 is at one of the busiest areas of Highway 9 because of all the shops at Frontier Village. The plan was to lower Highway 9 under 204 to connect the shops and highway, but Kris Olsen at the Washington State Department of Transportation said they ran into a problem.

"What we discovered when we entered into our technical analysis is that the ground water is about ten feet below the surface,"  she said.  "In order to resist that ground water pressure, we would have had to build some fairly significant walls and footings."

QuoteThe new design involves a series of four roundabouts; two on Highway 9 and two on smaller surface streets, providing access to the shopping areas.

Before I read the article more closely, I thought Western Washington was going to get its first Magic Roundabout.  Oh well.

Official WSDOT design page. It does not have the new roundabout options yet.  Their old interchange plans were overlaid on a satellite image, and you can see a marshy area on the southwest corner of the intersection.  They had to know the water table was high.


Hurricane Rex

I'm not opposed to roundabouts, but does anyone know the traffic levels here? It seems the levels may be a bit high for one.

LG-TP260

ODOT, raise the speed limit and fix our traffic problems.

Road and weather geek for life.

Running till I die.

Bruce

Previous discussions: https://www.aaroads.com/forum/index.php?topic=18003.msg2293483;topicseen#msg2293483

https://www.aaroads.com/forum/index.php?topic=18003.msg2329376;topicseen#msg2329376

I just passed through the intersection today on my way to and from Lake Stevens on the bus...it's a pretty big chokepoint from what I saw. I wonder why the elevated overpass for SR 9 isn't being considered...surely it can't be that bad compared to the current layout.

Bruce

Quote from: Hurricane Rex on February 07, 2019, 10:30:15 PM
I'm not opposed to roundabouts, but does anyone know the traffic levels here? It seems the levels may be a bit high for one.

21,000 vehicles on SR 204 and 32,000 on SR 9. SR 204 funnels a lot of traffic from the Hewitt Avenue Trestle (US 2), while SR 9 suffers from split personality disorder (country road or suburban expressway). SR 9 already has a few multi-lane roundabouts, and Lake Stevens has plenty of roundabouts on its own roads (SR 92 and Lundeen Parkway), so it shouldn't be a difficult adjustment.

compdude787

At the very least, WSDOT needs to put in a flyover for traffic turning left onto SR 9 NB from SR 204 EB. Simply putting in a roundabout isn't going to cut it.

jakeroot

#5
I bet the main roundabout might end up being three lanes. WSDOT has never done this before, but they're obviously desperate for capacity improvements. Hard to believe an intersection with 14 approach lanes could somehow operate worse than a roundabout with 8 approach lanes (two for each approach). A triple left turn EB to NB via a roundabout might work. Depending on the success of the SR-204 roundabout meters in Richland, they ought to consider metered entrances for this roundabout to handle afternoon flow.

As for a flyover, though I'm surprised they haven't at least considered the idea, it might be too tight. Ideally it would be two lanes, and there's just no room between Hwy 9 and Vernon Road for it to come back down to ground level. It would almost have to stay elevated all the way past Davies Road, which wouldn't exactly be a pretty sight!

compdude787

Wow, three lanes is quite insane for a roundabout! And yeah, I guess it would have been a bit difficult to fit in a flyover, sadly.

jakeroot

Quote from: compdude787 on February 10, 2019, 07:57:06 PM
Wow, three lanes is quite insane for a roundabout! And yeah, I guess it would have been a bit difficult to fit in a flyover, sadly.

It would be insane for WSDOT. I know of no other roundabouts in the state that have been proposed as three lanes, much less built.

To be clear, there is no official documents that indicate a triple lane roundabout as a consideration, but it would seem to me like the best idea. Though there would be a lot of crashes, if other triple-lane roundabouts are any indication, and it would not do a good job of facilitating cross-highway pedestrian/bike movements.



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