The I-5 express lanes are an underutilized asset. A relic of the days when peak flow into Downtown by car was the primary engineering concern, the express lanes generally flow freely with the exception of single-occupancy vehicles clogging the ramps at Mercer and Stewart. Meanwhile, reverse-peak freeway transit is probably one of the most miserable experiences in the region, as anyone caught on an southbound afternoon Route 41 or 512 can attest. The marginal benefit of ST2 is perhaps greatest for those riders caught outside the traditional commute. Last year, Community Transit used “the last $2m we could find” not for any added service, but just for I-5 congestion padding in their schedules.

It’s remarkable how I-5 is generally ignored in regional planning discussions. It was omitted from the massive transportation package passed last year in favor of new lanes elsewhere. While SR 520 gets HOV3 and I-405 gets dynamic tolling, there has never been any momentum for any type of HOV or transit priority from Northgate to Downtown other than the express lanes. I-5’s needed redecking and seismic rebuild loom silently as the state’s largest unfunded liability. Former WSDOT head Doug MacDonald may be curmudgeonly about light rail or Amtrak Cascades, but he’s absolutely right that I-5 is “a planning orphan.”

Though most (if not all) peak buses are set to be truncated with the completion of ST2 in 2023, that’s still 7 more years of people’s lives to plan for and accommodate.  And of course the physical asset will remain indefinitely. So what should we do with the express lanes?

In the near term, before Lynnwood Link opens, there should be a much greater urgency to think creatively given the historic construction crunch we are facing in 2018-2019, when a torn-up street grid will be asked to shoulder an unprecedented burden of surface transit. The Center City Connector, Madison BRT, 2-way Columbia, Viaduct Demolition, SR 99 tolling diversion, Alaskan Way construction, continuing Denny Substation work, the Center City Bike Network, the probable closure of the Downtown Seattle Transit Tunnel to buses, and the continued boom in private development will all conspire for two or three years of unprecedented pain (as the One Center City effort will attempt to address over the coming year).

One creative option would be to convert the I-5 Express Lanes to two-way operation and take them for transit/HOV3 only. Though various configurations of this idea have occasionally gotten traction over the last couple decades, any efforts have generally fizzled due to a lack of funding and political will. Most ideas have assumed a large capital construction program that would add things like center-access ramps from NE 45th. But if seen as a temporary mitigation measure, is there a low-cost way to make the express lanes bi-directional without pouring any concrete? I think there is.

Imagine a transitway that runs 2-way all day, with the middle lane(s) reversible with a zipper to accommodate extra peak flow. Every ramp to the current express lanes would be ‘unidirectionalized’, operating only in the direction of the outer lane it is nearest. Under such a scenario, all current peak routes that use the express lanes could continue doing so in at least 1 direction, but all routes could make at least partial use of the express lanes around the clock. For example, the inbound 41 would have to access the transitway via Ravenna Boulevard, but would have an unimpeded all-day path outbound from Columbia St to Northgate. And this would be a huge boon to Community Transit and Sound Transit 510/511/512/513, as all Snohomish County routes could use the express lanes in both directions all day.

Here’s a visual I mocked up. Buses could use Mercer, Stewart, or Pike inbound all day, and could use 2nd, 3rd, or 5th (with a new bus lane) to access Columbia Street, which would be transit only and would act as the sole outbound ramp from Downtown. Inbound buses such as the 41 could live-loop through Downtown and head out Columbia, laying over at Northgate. Terminating buses such as the 512 could continue down 5th to Atlantic Base. Peak period trips like the 400s could deadhead to Mercer or Stewart to begin their afternoon, but all routes would run in a counterclockwise service pattern.
Admittedly radical, but also relatively cheap. If this worked, we would guarantee better speed and reliability for a much broader segment of riders, especially for the reverse peak buses that get totally neglected today. Passengers with traditional commutes would balk at having to exit sooner, of course. But transit would never get caught in I-5’s misery again, at least between Northgate and Downtown. Once Lynnwood Link opens, we could revert the lanes back to HOV or even SOV once the need for most peak buses is obviated. In any case, the express lanes are antiquated and nearing the end of their useful transit life. We should think creatively about the best way to use them.

51 Replies to “We Don’t Talk Enough About the Future of the I-5 Express Lanes”

  1. What do you think the effect of this would be on the I-5 mainline and the 520 busses that have to use it? Wouldn’t thousands of cars have to shift to the mainline once the express lanes are cut by 67% for them?

    1. Even if traffic shifts, it’ll only do so in the peak direction, remember. Off-peak will be improved. And if nothing else, 520 riders have the option of exiting at Husky Stadium.

  2. Make the express lanes two-way transit only, and HOV or HOT (even if tolling is just at downtown ramps) on the upper deck at congested times. Build stations at First Hill, Convention Center, SLU, Eastlake, 45th, 65th, Northgate. BOOM: Grade separated bus rapid transit serving dense, congested areas. Stations could be used as pedestrian connections where current crossings are miles apart (SLU – Capitol Hill).

    Treat city streets serving the converted express lanes (Columbia, Pike, and Mercer) as transit-only (Mercer could be half transit and the other half as regular street since it’s wide enough to be two streets, but does a horrendous job of moving people). Then it might be possible to move both North-South and East-West, and actually get around in this city.

  3. In the Golden Gate example, the zipper truck was chosen because the lanes were previously switched manually with little rubber pylons that a crew member would drop into holes as lanes changed throughout the day. The old manual process on the Golden Gate Bridge was much more dangerous and time-consuming than the zipper truck! Because the North Seattle I-5 express lanes are automated, this level of labor to switch directions is currently not required so a zipper truck is harder to justify.

    I would rather see the initial energy go into rethinking the segment north of 85th. It’s next to Northgate Link and Northgate Transit Center. HOV direct access ramps, an east-west exclusive transitway (maybe even ultimately tying in Lake City and 522 to the east and Aurora and Ballard to the west) and a good drop-off/pick-up flow.

    I do agree with you that the way that these express lanes are used could be different. With Link coming, I’m not convinced that we still need all those Downtown exits and entrances.

    One other provocative concept would be to simply repurpose and reconstruct the express lane part into a lower-speed, two-way street (not a freeway/interstate but more of an arterial/expressway) with at-grade intersections instead of overpasses (overpass and road construction would be needed), along with occasional ramps to and from the I-5 freeway lanes. WSDOT could then close off several local ramps that are on I-5 today. That would eliminate the need for the daily lane reversals entirely as well as ease some of the weaving problems and on-ramp queuing problems that occur on the roadway today. Of course, it would take years of study and sophisticated analyses to device how best to design this.

    1. Al, expanding on your idea, I have always thought that the express lanes would be a great extension of Mercer Street – that is, if you’re going east on Mercer and don’t turn anywhere, you’d curve onto the express lanes, and cross the ship canal. You could then design it the lanes next curve onto Lake City Way. So, Lake City Way and Mercer essentially become a single continuous roadway.

      1. Adding to your idea: Building a off-ramp/on-ramp T intersection with a signal to get to and from 522, and then restriping the mainline to restrict a Mercer/522 weave would then eliminate the Mercer weaving problem.

        I’m not sure how things south of Mercer or north of Lake City way would work. It might be possible to drop in separate one-lane, two-direction HOV lanes north of Lake City Way. Maybe a second arterial would then run from Lake City Way to Northgate. There’s plenty of right-of-way north of 85th.

        South of Mercer, it could be another north-south street with a few connections westward to South Lake Union or Downtown as is feasible — or it could just be a long off-ramp/on-ramp from the beginning of the express lanes all the way to Mercer.

        Here’s an even more provocative additional idea: Use the express lane areas south of Mercer as a pre-dug alignment for the green line LRT so that the second expensive and disruptive Downtown tunnel wouldn’t have to be built. It would save billions and get transit to SLU years faster. It would require moving the transfer point from Westlake to Convention Place, and/or rethinking how IDS is laid out. Still, it would be much easier to do than the current deep tunnel mess we’ll have to have through Downtown. It would all need to be studied..

      2. I like express lanes to rail conversion. Makes for a better Madison station. But can you give up the combined station at Westlake? Maybe, if you had a station at Pike/pine before heading towards the proposed Denny station. Can use convention center, that ship has sailed.
        This would certainly be way cheaper than a new tunnel.

      3. The Westlake transfer challenge would certainly be a big one. Still, addressing that, perhaps by reengineering a short section of track under Boren to add a new center platform station, would seem much less costly than the Downtown tunnel would. Think of the savings in cost and time! It would save so much that connecting the two lines near Westlake would seem to be much cheaper!

        A scenario using the I-5 Express lanes:
        – A Harborview station, located at or south of James with an elevator tower to Harborview Park
        – A Madison/Seneca station
        – A Pine/Olive station, either tied to Westlake for transfers with moving sidewalks, or to a new center platform station near Boren, or a Denny station tied to Capitol Hill with a set of underground escalators and/or moving sidewalks or two funicular subways

        Along Harrison:
        – A South Lake Union station between Westlake and Fairview
        – A Seattle/Gates Foundation station between Fifth and 99
        – A Lower Queen Anne Station

        Frankly, Westlake is an awkward place for a transfer because it has side platforms as well as an apparent need to go pretty deep for the green line platform according the sketches. A different configuration could be to build a Y with tracks going into Capitol Hill around Harrison or John (possibly extendable eastward as the elusive Metro 8 line) and aligning just below the center platform at Capitol Hill station. A scenario of lines:
        – Tacoma/SeaTac/Rainier Valley/IDS/Ballard
        – SeaTac/Rainier Valley/IDS/South Lake Union/Capitol Hill or CD
        – Capitol Hill or CD/South Lake Union/ Ballard
        Maybe the Downtown tunnel cost savings would even allow for a subway bore further to a Central District (Madison/19th? Union/23rd?) station or as the end station
        The advantage to this option is that it would off-load the Capitol Hill to Westlake crowding, which is projected to be the most crowded segment, as well as lessen the need for the Ballard-UW connection.

        Of course, all this would need study.

    1. This has been discussed before and really works with the terrain if space could be made. Probably West of traffic entrance around Roanoke and 42.

  4. Some thoughts…

    Putting the only on-ramp on Columbia would require a radical redesign of downtown service, even more radical than you’re envisioning. Routes like the 41 could lay over at Northgate or Lake City, sure, but what about the 512 and 522? They’ll come south from Stewart, lay over in Sodo, head back north to Columbia… and then what? Will they go straight onto I-5, and leave Westlake unserved?

    (Plus, if you let any cars onto the Columbia on-ramp, it’ll instantly be clogged, and probably a lot of the downtown street grid too.)

    Also, I’m not convinced all off-peak service could use this; at a minimum, you’d need to give up the 45th St freeway station. I’m not sure how many people board there, but I’d guess it’s an important connection point for the off-peak 512.

    But… if this does happen, I think you could allow a few reversible ramps. In the AM peak, with the orange lane southbound, buses could enter at Northgate and merge into the orange lane with just a little restriping of the gore point. You might be able to allow an exit on Columbia, too, though I’m not sure there. Also, in the PM peak, you could turn Pike into entrance-only to avoid the Columbia problem. (The 522 would be the only bus using it southbound, and that can just go to Stewart.)

    1. The entrance-only versus exit-only lanes above are not in any way a choice. They are predetermined based on what side of the express lanes the ramp is on. Not following this scheme either means entering into oncoming traffic or spending huge amounts of money to move ramps around. Both are no-gos.

      1. My scheme wouldn’t require changing any of that. I’m pointing out that with the orange lane reversible, we could make Northgate two-way in AM peak and reverse Pike in the PM peak without intersecting oncoming traffic at all.

      2. Agree, Donde. Especially Mercer, which I think could just be a mistake. Because the northbound Mercer entry ramp already serves both regular and express lanes. Transit lanes through the Mercer area are still a favorite of mine, especially after CPS closes.

        But good Lynnwood and Everett service are very important for seeing to it that our north end terminal has best possible service until they get their trains. Best measure for getting accustomed to transit, and resisting temptation to sprawl in the meantime.

        From some long-time experience through Ash Way Park and Ride, it’s glaringly ridiculous that ramp system from both I-5 and I-405 are still unfinished. Must lose us more than enough in service hours to finish the job.

        Mark Dublin

    2. Yeah I think it actually makes the most sense to keep both pike and Columbia bi-directional like today. There is no logistical reason not to and that allows you to basically keep the existing service patterns for Metro and Community transit with greatly improved reliability. It also reduces the complaints from existing express lane users who use those entrances/exits.

  5. They would need to add some ramps to make it really usable, but one interesting thing is that they could hook up SR-520 HOV lanes to the express lanes this way.

  6. A few tidbits.

    1) There are separate on ramps off ramps for Mercer Street it is not a combined ramp unlike Pine Columbia and Stewart.
    2) 303 is listed twice, I am assuming 303 would get off at Northgate.
    3) 355 likely runs mainline anyways given its entrance/exit at 85th.
    4) While 522 would likely have some significant gains in the off-peak hour heading SB, you would lose that time heading NB in the PM. I would almost consider sacrificing the 85th St. stop given it previously wasn’t a part of it to get 522 to Northgate and start it at 125th. Those extra minutes could then be reinvested into frequency potentially.

    I do agree that the 5 express lanes if 5 gets rebuilt should be a 4x2x2x4 configuration with center being HOV 3+ during peak hour direction. That would help alleviate congestion heading NB making it easier for buses from the south to get onto the SODO busway. That would help utilization between the peaks where SB 5 jams to Ship Canal regularly.

    I am not sure if you could politically sell this but I have heard from Bruce that it regularly takes 15 minutes to get off I-5 at Stewart on the Snohomish County buses, my thinking would be is to have a dedicated bus ramp during pm peak.

    1. So Mercer could be bidirectional all-day under this plan? That’s great! That also means some northbound buses, instead of taking Columbia, could go up new bus lanes on Virginia and Fairview to Mercer!

      (I still sort of like the idea of reversing Pine for the PM peak, as I pointed out above, but bidirectional Mercer means it’s nowhere near as important.)

      1. Yes, if you look here

        It shows a right handed entrance. It takes a long time to traverse downtown. Unless one street had TSP out to Virginia and Fairview, you want the buses running on the freeway to get to it ASAP. I would like to get buses off of 5th Avenue given its car sewer nature and being caught in it previously on a 545, I ended up taking the tunnel to avoid the congestion.

        Under this plan you could not reverse Pine in the PM peak without requiring all traffic to get off at Stewart and Mercer. That would end up creating congestion like it normally does to Northgate, eliminating the benefit of two way express lanes.

      2. Yes, TSP would definitely be needed on Virginia and Fairview, at least.

        In the PM peak, under this plan, wouldn’t southbound traffic already be exiting at Mercer, Stewart, and Pine, though? The orange lane would be northbound, so where else would they be going south of it? Why would taking away the Pine exit be such a change?

      3. Pine would be a left entrance meaning in order to have traffic come on from Pine during the PM peak you would have to have the entire facility running NB until Stewart. Otherwise you would have one lane going south in the middle and two lanes going NB on both sides.

      4. Would the orange lane really be southbound in the PM peak, though? Zach’s post said it’d be peak-directional, so it seems to me it’d be northbound.

  7. A few thoughts: First of all, this is a brilliant idea. Well done. But i can’t sweep aside some thoughts about an otherwise wonderful presentation:

    The marginal benefit of ST2 is perhaps greatest for those riders caught outside the traditional commute.

    marginal? MARGINAL? Are you serious? ST2 has marginal benefits? You are joking right? ST2 is the greatest transit improvement to hit Seattle since the bus tunnel (which was a while ago). It is, arguably, greater. Holy cow, you have mass transit to the U-District (not just the hospital) and you also have Roosevelt, Northgate and (oh wait) Lynnwood. Basically you have provided the north end corridor with everything they could ever want (assuming obvious stations like NE 130th) and you call it marginal? Jeesh. Tough crowd. Wasn’t there something else in ST2? Hold on, it will come to me. Oh yeah — a light rail line to Bellevue! Or are you saying buses are good enough? ST2 basically solves the biggest transit problem from the north and the east, and now it is marginal. If ST2 is marginal, I wonder what you would call ST3 (negligible?).

    Second, your graphic doesn’t include the bus transit tunnel. This is kinda important. For the period in which we are dealing with (post ST1, pre-ST2) it is essential. If I ride the 41, I would like to know if it just leaves the (grade separated) tunnel and enters the (HOV only) express lanes or not.

    Other than that, a brilliant presentation. You seem to understand the fundamental problems that exist while we wait for rail, and have a very creative way to solve it. My guess is it won’t matter. As nice as this could be (Good God, it would be nice to get from Northgate to downtown in a reasonable amount of time in the afternoon) I have a feeling no one will mess with anything, because this is a timid city. Better to just live with it. Tell folks that eventually it will get better, and change the subject. Just look at the tunnel. It is a mess — not good for trains or buses. There are ways of solving it (off board payment for buses, payment gates, etc.) but no one wants to address the issue, so we just live with it. Metro does what it can (officials with off board ORCA readers along with back door boarding) but no one has the guts to do something as bold as this.

    1. Presumably his graphic doesn’t include the transit tunnel because one of the major causes of the coming traffic crunch is the closure tunnel to bus traffic. I’ve seen speculation on this blog that the ramp to the express lanes might remain open, but my guess is the limited utility of that plan is not going to be enough to delay the tunnel handoff to Link.

      1. Chris, and anybody else, do we have any solid idea when joint-ops are going to end? Would be good if Transit has anything to say about it. Or publicly demand it if it doesn’t. DSTT was here before expansion plans were a twinkle in anybody’s financially unaccountable eye.

        And ’til our demands are met, fill up the Convention Center with jovial exploding cigar-distributing, indecently- harassing, handshake buzzer-packing businessmen in 1933 suits, wearing turkish hats, with Laurel and Hardy’s “Sons of the Desert” replayed 24-7 on the walls.

        Per usual MO, conversion will be Hhistory’s most courageous indecision, without any warning at all. As Tunnel operations have generally been planned and run.

        So to me there’s nothing lost to get the DSTT organized a tenth of what it should always have been, so Darren McGavin on “The Night Stalker” doesn’t find unsettling results of standing Route 41 loads that hadn’t cleared Convention Place when construction started.

        However, if he works for The Seattle Times, whether he believes the poor little guy stuttering about the dead people walking around down there, his Editor will definitely assign him to the campaign against the next ST.


      2. My understanding was that the buses were going to be kicked out when Link gets to Northgate. At that point, a lot of this becomes moot, or at the very least, there are a lot of other options. The 41 goes away for sure (or at least the part that goes from Northgate to downtown) while other buses will likely be truncated as well.

        I know the convention center work is supposed to mess things up, but I haven’t been following that, and I don’t know the details or the timing.

      3. The convention center stuff is what you need to worry about. That is supposed to start in the summer of 2017.

      1. I thought that maybe I had misinterpreted the sentence, so I read it over and over again, and I still don’t get it. I appreciate your explanation, but it still doesn’t make sense to me. I’ve never heard or read “marginal” used in that way, nor can I find a definition for it that would make sense in that manner. I would assume you’re right (I just misinterpreted what he wrote) but I don’t see how you can take the sentence any other way. If you feel like explaining some more, please do.

      2. Ross–“marginal benefit” is an economics term, meant to only point out the added benefit in comparison to not having ST2. It’s what most people would just refer to as benefit, but more technical in language.

      3. So why he is using an economics term (in a weird way) when simple English would suffice? That is just bizarre. This isn’t an economics blog. It is a transit blog, and Martin stresses the use of plain English, not slang. So why allow economics jargon? I just think it is an editing failure, on an otherwise outstanding paragraph.

        I looked up the word “margin” ( and the only meaning that makes sense in that sentence is the one I mentioned. I can’t help but think that people glossed over that sentence, and just assumed the meaning they wanted. I think your meaning is the right one, Mike — it is the only one that makes sense. There is no definition that matches the word “additional” (and if there was, why not just use “additional”). Put it this way, what if i wrote the following:

        I believe ST3 will have a marginal benefit to those living in Tacoma.

        Now compare that one to this one:

        I believe ST3 will have an additional benefit to those living in Tacoma.

        I guess I am still baffled by the fact that he didn’t write something like “Perhaps the greatest benefit of ST2 is that it helps riders caught outside the traditional commute.” The thing about that sentence (which was probably what he meant) is that I would have excitedly highlighted that sentence, because not only is it true, but its meaning is as well! I would love to quote that, and reference the rest of the paragraph, because it is a very important concept when it comes to transit discussions. Not every trip occurs towards downtown at rush hour. It is one of the strongest arguments for light rail to Northgate and what separates it from plenty of other proposals.

        Anyway, I guess I need to brush up on my economics terms or just stop being pedantic. I really doubted that Zach thought the improvements made by ST2 were “not of central importance”, “limited in extent, significance, or stature ” (i. e. “marginal”) and I hope everyone who reads this post (especially those that don’t usually read this blog) understands that as well.

    2. Ross,

      “Marginal” doesn’t mean “small”. It means “additional”. The meaning is clear to me when I read the sentence.

  8. It would not only be a huge benefit to ST and CT, but also BoltBus, Amtrak Thruway, Belair Airporter, and others.

    1. One favor, Glenn. Since I’ve got a haz-mat suit I can unzip and safely dispose of upon deboarding, in the name of Transit I’m willing to investigate in person if the Department of Agriculture will clear Greyhound’s newer buses for livestock.

      Will also verify drivers’ names to see if they’ve been recently fired by the California Department of Corrections for below-standard passenger handling violations. Won’t look for criminal records, because the two on my last Sacramento-Eugene ride several years ago have rewards out for not turning them in.

      If Greyhound has in fact been bought by a Turkish long distance bus line (they have stewardesses!) and probably incense and spiced tea on board and kebabs at rest stops, then you can let them use the lanes. I’ll text on service quality when I get to Tacoma. Five Yelp stars means Los Angeles.


  9. Is your plan to eliminate the 512’s stop at 45th St? If not, the 512 still won’t be able to use the express lanes. If so, you’ve just added 30-45 minutes to any trip between the U-district and Snohomish County, as well as taken away an express route between the north-west part of the U-district and downtown, which is quite useful in the interim period before the U-district station opens.

    1. Any chance of “Flyer Stop” with elevators and escalators to platforms under NE 45th? For passenger load the 512’s will probably carry, could be worth cost.


      1. Perhaps – but it’ll only be useful until Lynnwood Link opens in 2023. Since ST still hasn’t put in northbound ramps at Ash Way, or a freeway station at the Olive Way ramp…

    2. Thinking outside the box a little here, there is enough room at 41st for a right side platform on the southbound side. The shoulder would have to be widened a bit to give enough room for a bus stopping to get completely out of the southbound lane, but it could be done for a couple of million. A similar one could be built on the northbound side just north of the 42nd off ramp diversion.

      Remember, there would only be buses in the outside lanes which means that the drivers would all be professionals. A driver pulling out from these stops could be confident that the other drivers would be careful and yield when appropriate. Plus there just wouldn’t be all that many vehicles in the lanes.

      And, yes, it’s a bit of a walk down to 40th to the 31/32, but it’s not particularly steep and dozens of people a day have walked that way for decades to avoid the noise and danger of the 45th overpass. \

      I know it doesn’t get you a direct connection from the 522 and 512 to Ballard, but it does get them to Fremont which might be more of a destination. Admittedly, the walk from

  10. We might turn some silent opponents into vocal supporters if we could provide some measures for interstate trucks. Does anybody know whether over the road truck schedules can be adjusted so that trucks get the lanes at night, when buses don’t need them?


    1. OTR truck schedules are mostly dictated by the operating hours of their shippers & receivers, not traffic conditions. Which means they usually end up sleeping at night and driving in the day, even if they’d rather keep the opposite schedule.

      OTR Truckers currently go to great lengths to avoid being caught anywhere near Seattle overnight, due to a severe shortages of places for them to park and take their mandatory 10 hour rest break. There’s only two truck stops anywhere near Seattle – one in North Bend and one on the Puyallup reservation – both with parking that fills up completely every night.

      But daytime truck traffic wouldn’t cause congestion enough to interfere with bus operation anyways, IMO. I’ve long advocated some sort of partnership between trucks & transit in funding/sharing dedicated roadway space. SOV congestion is our common problem.

  11. There has been work done on this question over the years. One concept proposed in the late 1990’s and revisited regularly would carve off the west-most lane to always run southbound. In the afternoon it would be barrier-separated (with a zipper) and in the morning it would be concurrent flow (with zipper out of the way). A slip ramp north of Ravenna would allow HOV’s in the southbound mainline to cross over to the SB lane, and a similar ramp near Mercer would allow movement back to the mainline and the lane would end at the Mercer St. offramp (or the lane could simply serve Mercer St.) It requires some very tight geometrics, but could be possible.

    This concept is not obviated by rail. For at least the next 20 years we do not have sufficient regional transit access to South Lake Union, Denny Triangle and First Hill. (Because of that, the mode share in SLU is far less than the old downtown, despite developing similar density. What a missed opportunity!) Regional express buses could still serve these markets effectively using the express lanes and the new SR99 tunnel if anyone thought to do it. If an intensive bus corridor was developed on 8th St under the convention center to First Hill, express buses serving SLU could also serve Denny Triangle and First Hill to provide the regional access needed until rail arrives 20 years from now.

    1. The use of 8th is a great idea. I tried to get people to think about re-routing the #2 that way to get it out of the Spring mess, but that’s going to be ameliorated by Madison BRT.

      But using it as a transit alternative to Boren is excellent! Hardly any traffic goes that way, so just close the street to everything but buses, commercial traffic and people headed into the garage.

      1. The thing I like is that it connects up a string of destinations that all need better regional access into a route with high demand among them, so high frequency can be provided cost-effectively. I also like (1) that it would be doing something rather than nothing about transit to SLU, and (2) it would connect medical and bio-tech centers that likely have a lot of interchange between them. This is especially true if the SR 520 service exited at Montlake, served the UW hospital, got back on the I-5 express lanes at 42nd to Mercer (at least in the peak direction).

        It seems to me this is one of many urgent regional transportation issues that are simply being ignored because they don’t immediately call for a rail solution.

    2. Yes. When the express lanes are SB today, the NB mainline is rarely congested, from what I’ve noticed. This could even be a permanent barrrier, with the exit to Mercer basically beginning at the Ravenna on ramp. Even with nothing else changing, (SOV/HOV/… designations unchanged, except would be a win over today’s setup. But it would be an opportunity to tweak those things too.

  12. This is a great plan! And absolutely necessary, sans any alternative.

    Sadly, I don’t think the “BRT fans” will push for it, having done their only job of defeating the latest transit ballot initiative, so it will fall to the actual transit and BRT fans, i.e., all of us pushing to pass ST3, Regional Proposition 1.

    I would actually reserve the full capacity of the express lanes, so that we can allow 2 lanes of peak-direction buses, and still be able to deal with breakdowns nimbly. Then, plan for increased capacity, as SOV drivers stuck in the non-express lanes shift to the now-faster buses. The fact of the buses being faster will fund some of that extra service. Buses in free-flow on I-5 should draw a heckuva lot more ridership, self-fund the extra bus service, including more counter-peak service, and give ST a better idea how much capacity to plan for when Northgate, Lynnwood, and Everett Link open.

  13. In the longer term how viable is using the express lanes ROW for a commuter and high speed rail line northwards out of Seattle? Given EMUs and HSR trains ability to generally handle curves and grades well it seems like this is the best route we would have available through the northern suburbs without building a very long tunnel. It also serves major nodes and transfer points to buses/link along the way (e.g. at Northgate people transfer to Link to head to U district).

    My more controversial belief here is that Link to Everette beyond Northgate/Lynwood should actually be build as a commuter/HSR line replacing the coastal route instead. So follow up question with ST3: how will building link along I5 impact the ability to build HSR/commuter rail along that corridor?

    1. Pondering the wheel ruts of Roman chariots along cobblestone roads in Europe, or gazing upon the ruts created by endless wagon trains along the Oregon Trail leaves only one conclusion.
      Where topography and development restrict ROW to narrow corridors, those corridors inevitably get repurposed to the next level of highest and best use.
      With that said, I-5 is the best route (relatively straight, flat and wide) through the middle of the Seattle hourglass. Even though we’re decades behind the rest of the civilized world in HSR and regional rail to move about our Cascadia Corridor of cities – we’ll eventually get there.

  14. Zach, someone may have mentioned this upthread, but the plans for the west end of SR520 include a connection to the reversible lanes. If you make the easternmost lane transit only northbound, 520 buses can only use the HOV/bus lane northbound.

    That may not be a deal killer, but I expect WSDOT would frown on it.

    1. My thought was that we do this until 2021 or 2023. The “Rest of the West” SR 520 project likely won’t be done until then.

  15. The premise of Zach piece is that we are headed toward a tough constricted time. One option would be to question the timing of the projects under way; or, is this the correct time to build the CCC streetcar or prematurely close the transit tunnel to buses? The deep bore and seawell are late; the Denny Way substation project will be disruptive; East Link will be disruptive. The one center city studies today should inform those timing decisions. That buses will be taken from the transit tunnel in 2021 has been a planning artifice for the convention center project. In the ST service implementation plans, they show six-minute headway in 2021, so joint operation could continue. See page 112 here:
    It is very short Link headway that ends joint operation, not the extent of Link. The points RossB, Mark Dublin, and Brent have made about faster fare collection are fair as well.

    1. The convention center expansion, which by nature starts at the foundation, which will be where Convention Place station is now, is supposed to start in the summer of 2017.

      How sure are you of the 2021 end of tunnel bus service?

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