WA-18 possible I-605?

[dvferyance]

According to Wikipedia WA-18 was been thrown around as a possible I-605. While the WA-18 freeway doesn't quite connect to I-90 if it ever did would make a nice alternative to get between I-5 to I-90 than the much more crowded I-405.

[corco]

It's functionally already used by everybody heading from I-90 to Tacoma instead of I-405. I don't know that it really needs to be a full interstate - the part that is still two lanes has very few turns, so traffic moves pretty well. Maybe one day.

[Bruce]

The north half will not be built in my lifetime, for sure.

Designating WA-18 as I-605 would be pointless unless we can get federal assistance in making some improvements to it (the ongoing widening around Tiger Mountain and, more critically, rebuilding the WA-167 interchange to have full directional functionality).

[jakeroot]

...and, more critically, rebuilding the WA-167 interchange to have full directional functionality

Are there any actual plans? I haven't heard jack about a fully directional interchange since it was originally built.

[sparker]

IIRC, there were "pipedream" plans tossed around in the late '90's/early '00's that used the western portion of WA 18 as the south end of a projected I-605; the plans were to veer north somewhere around Hobart and cross I-90.  It would then have generally followed WA 203 to around Monroe, then NW along US 2 to return to I-5.  To say the least, that plan found little favor with either WSDOT, regional planners, or even the Seattle press.  It probably exists today as a line on a map on a shelf somewhere; the odds against anything like this being done in the foreseeable future are slim & none -- today, no one in any official capacity in the region would think of undertaking anything that might attract development to the outlying valleys on the western Cascade slopes.

[Henry]

Yes, I remember that proposal. FWIW, it's a pipe dream that will never be realized, at least not in my lifetime.

[kkt]

In particular, heading north from Hobart would put it through Tiger Mountain or Squak Mountain.  They are both very popular day hike destinations for picnickers and hikers of all ability levels and are legally protected, as well as being steep terrain prone to landslides that would be difficult to build on.

WA 18 is also short of interstate standards in length of merge lanes, how closely exits are spaced, etc.  It very much shows its origins as a cheap upgrade to a 2-lane country road.  In addition, as already pointed out, the junction with 167 is a couple of ramps short of a full interchange.

I don't think even the southern half of proposed I-605 has any chance of becoming an interstate.  I do hope they build the missing 167 interchange connections, though.

[The Ghostbuster]

While it might be nice to make WA-18 Interstate 605, it likely isn't practical. Maybe some other corridor would be better.

[TEG24601]

While it might be nice to make WA-18 Interstate 605, it likely isn't practical. Maybe some other corridor would be better.

I always thought that starting around 512, then utilizing parts of 167 or 169 to travel North, connecting to I-90 near the current terminus of SR 18, then Northward along the 202/203 corridor to Monroe, connecting with the already planned US 2 bypass of Monroe, then NW toward I-5 at either Conway or Burlington; or supplant US 2 westward, then utilize the pipe dream connection directly to SR-526 in South Everett, then both 525 and 526 would continue as x05s.  Of course, I-605 is certainly a pipe dream, there are some major structural and traffic issues along the I-5 corridor that cannot be solved through mass transit, and only making trains more viable to local deliveries can even hope to address, which makes additional lanes or roadways the only viable alternative.

[sp_redelectric]

1.  Wouldn't SR 18, if designated an Interstate, need an spur number since it would not reconnect back to 5?  (105, 305, 505, or 905)

2.  Any talk of designating SR 512 and SR 167 either as an Interstate, or as an extension of I-405?  (Especially since SR 167 does not connect to its parent route, SR 16)  I would imagine that the simple step of designating that freeway as a contiguous route would alleviate some congestion from the interstate travellers (read: people from Portland) who would suddenly realize there is another route north rather than I-5.

[kkt]

1.  Wouldn't SR 18, if designated an Interstate, need an spur number since it would not reconnect back to 5?  (105, 305, 505, or 905)

Originally 605 was proposed when advocates wanted a northern connection from I-90 north to Everett or Marysville or thereabouts. 

However, the rule is pretty fuzzy.  Many times roads have been interpreted as loops if they connect from one interstate to another around the edge of the urban area, like 18.  Spurs would be from an interstate to a non-interstate.  And many times the rule has been ignored due to lack of available numbers or changes in the scope of the freeway after the number was assigned.

2.  Any talk of designating SR 512 and SR 167 either as an Interstate, or as an extension of I-405?  (Especially since SR 167 does not connect to its parent route, SR 16)  I would imagine that the simple step of designating that freeway as a contiguous route would alleviate some congestion from the interstate travellers (read: people from Portland) who would suddenly realize there is another route north rather than I-5.

[Bruce]

WA-167 is often more congested than I-5 is, so there's no real incentive to encourage through-trips to use it. If anything we should be telling them to stay put on I-5.

[sparker]

Bruce is essentially correct -- 167, even in freeway form, was always intended to be a local server for the Kent-Auburn area, allowing commercial traffic to the industrial areas of the Green River valley to more directly access their destinations without having to use the east-west local roads from I-5.  The 167 extension back to I-5 in Tacoma will more or less complete that concept; 512, while practically an extension of 167 around Tacoma, will likely resume functioning as a localized bypass once that extension is completed.

WashDOT never intended 167 as a detour route for I-5 -- but over time, despite those intents, the increased housing development in & around the Green valley caused it to be used as such; hence the deployment of HOT lanes along the northern portion of 167 in an attempt to address the congestion issue. 

The last time I heard any other developmental rumblings coming from this area, they concerned an extension of the WA 509 freeway section south and east back to 5 -- or at least WA 99/Pacific Highway.  Is this still an active proposal, or has it been shelved/back-burnered?   

[jakeroot]

The last time I heard any other developmental rumblings coming from this area, they concerned an extension of the WA 509 freeway section south and east back to 5 -- or at least WA 99/Pacific Highway.  Is this still an active proposal, or has it been shelved/back-burnered?   

Still very much in development. There is funding for phase 1 of the project (tied together with phase 1 of the 167 extension): http://goo.gl/8gYI82

Development has taken a long time due to several ecologically-sensitive areas in the way, as well as local opposition. Additionally, SeaTac Airport has, on several occasions, forced redesigns of the freeway for several reasons, none of which I fully understand.

Here are some new-ish design visualizations:

[sparker]

Nice pix!  Another question:  If 509 is indeed "repurposed" as essentially a south airport access route -- as well as a way to get to Burien (or even up to W. Seattle) without using 518, what will happen to the disconnected portion of 509 east of Tacoma?  Will it be redesignated as another number (hey, 514's available) or simply relinquished to Tacoma, the county, or even the Port? 

[froggie]

Theoretically, the freeway segment of the disconnected 509 near the Port of Tacoma could become part of a 167 extension once the remaining 167 freeway segment from Puyallup to Tacoma is built...the project includes a connection to the freeway near the port.

[compdude787]

I have a feeling that they might decommission it, but I'm not 100% sure. I always thought that it would end up being concurrent to I-5 between the south and north freeway segments of SR 509.

[Quillz]

1.  Wouldn't SR 18, if designated an Interstate, need an spur number since it would not reconnect back to 5?  (105, 305, 505, or 905)

Originally 605 was proposed when advocates wanted a northern connection from I-90 north to Everett or Marysville or thereabouts. 

However, the rule is pretty fuzzy.  Many times roads have been interpreted as loops if they connect from one interstate to another around the edge of the urban area, like 18.  Spurs would be from an interstate to a non-interstate.  And many times the rule has been ignored due to lack of available numbers or changes in the scope of the freeway after the number was assigned.

2.  Any talk of designating SR 512 and SR 167 either as an Interstate, or as an extension of I-405?  (Especially since SR 167 does not connect to its parent route, SR 16)  I would imagine that the simple step of designating that freeway as a contiguous route would alleviate some congestion from the interstate travellers (read: people from Portland) who would suddenly realize there is another route north rather than I-5.

Yeah, what exactly makes a "spur" or a "loop" is pretty difficult to define. Frankly, I think *if* WA-18 ever did become I-605, it would qualify as a loop since it would connect two interstates. To me, that has largely been the definition I tend to work with.

That said, I just came back from vacationing in Washington and drove on WA-18. It's a nice highway, but a long, long way away from ever being an interstate. It still needs a lot of work.

[jakeroot]

Frankly, I think *if* WA-18 ever did become I-680,...