FOLLOWUP: SDOT explains why motorcycles aren’t allowed on West Seattle low-bridge at all times

(WSB file photo)

During Wednesday’s meeting of the West Seattle Bridge Community Task Force (WSB coverage here), a member asked why motorcycles aren’t allowed to use the low bridge at all times. SDOT’s Heather Marx said traffic engineers had recommended against it, calling it a safety issue, and promised to provide the inquiring member with the detailed explanation. We subsequently requested it, since many WSB readers have asked, and received it today:

While a motorcycle is physically smaller than a car, they still require roughly the same amount of room on all sides to travel safely. This is because a large truck or bus needs just as much room to stop safely when they are following a motorcycle as they do for any other kind of vehicle. While two motorcycles could theoretically travel side by side, most motorcycles would likely be travelling on their own and occupy and entire lane.

This means that from a traffic engineering perspective, motorcycles take up essentially the same amount of room as a car. This is especially true at traffic signals or in stop-and-go conditions where congestion is created by the cumulative reaction time of every individual driver waiting to go forward after the vehicle in front of them moves ahead. In this situation, the number of vehicles in a line of traffic is just as important as the size of each individual vehicle, and so motorcycles could be expected to add to congestion at the Chelan 5-way intersection just like cars do.

We also have safety concerns about motorcycles travelling next to large trucks and buses in stop-and-go conditions, especially because congestion would likely increase considerably if more motorcycles took this route.

If you have a question about that – or any other bridge issue – note that SDOT will be part of both community meetings we’ve previewed for tonight, the Town Hall at 6 pm and West Seattle Transportation Coalition at 6:30 pm.

54 Replies to "FOLLOWUP: SDOT explains why motorcycles aren't allowed on West Seattle low-bridge at all times"

  • Wendell July 23, 2020 (2:04 pm)

    Pure, unadulterated horse crap.

  • wendell July 23, 2020 (2:34 pm)

    So going by this crazy logic, I shouldn’t ride my bicycle on a public highway for these safety reasons?

    I’m guessing this lame explanation comes from someone that’s never ridden a motorcycle – making policy decisions for those that responsibly commute by motorized transportation.

    FWIW My commuter motorcycle gets 70mpg, and only weighs about 400lbs fully fueled… and can fit in the back of a midsize pickup.

    • Aerial Observer July 23, 2020 (3:27 pm)

      What do you find “crazy” about a motor vehicle creating the same traffic flow as other motor vehicles in the same traffic lane? The only difference is a motorcycle, as you note, is physically smaller than other motor vehicles. As SDOT notes, it effectively takes up the same amount of space on the roadway, despite smaller physical size.

      A motorcycle accelerates faster than a car or truck, and it can change lanes faster. The former can cause problems in heavy traffic (one vehicle’s motion not synchronized with the other vehicles in the flow) and the latter is absolutely no help at all on the Spokane St. Bridge, which is one lane in each direction.

      So again, what property or properties of motorcycles contradict SDOT’s logic?

      • 22blades July 23, 2020 (4:59 pm)

        SDOT’s view of motorcycle / scooter / moped contradicts established practices in a number of ways; 1. State & Federal Highway planners afford HOV lanes to Motorcycles &Scooters that can meet Federal Highway standards. 2. Many municipalities, especially internationally & even the city of Seattle, have adopted the use of motorcycles as a valid & unique form of Policing & even emergency response. 

      • Michael July 23, 2020 (5:08 pm)

        It only takes up more space if you’re doing it wrong.  SDOT claimed safety but then listed traffic flow concerns.  Motorcyclists already have to deal with vehicles that don’t see them, that’s table stakes.  This is just SDOT once again ignoring a transportation method that would help all of us get around.

      • Lou July 23, 2020 (7:15 pm)

        How dkes a motorcycle occupy the same space than a car? Have you ever ridden one? Why is space on a lane an issue? What does changin lane rate have to do with anything when talking about a single lane scenario? You’re just told something that makes 0 sense and go with it because you’re told to do so? Under this same moronic logic, bicycles shouldn’t be allowed on the bridge or any road either when using the bike lane! On a side note, where are the responsible ones for having taken care of the bridge but didn’t? Anything from city council members to mayors and governors all the 34 years the bridge operated on our taxes! 

    • Talmerian July 23, 2020 (3:33 pm)

      Definitely cutting and pasting this argument for the next time I’m told a road doesn’t need infrastructure for people who ride bicycles “because there’s a shoulder on the road.” It’s safe enough for people to ride next to large trucks and buses moving at high speed – if the alternative is creating space for road users. Weird for a lighter, more agile vehicle to be constrained by parameters for larger more ponderous vehicles.I wish they’d just say, “Both bridges could fall at any point! Stay off them!”

    • West Seattle Mad Sci Guy July 23, 2020 (3:56 pm)

      Would a bicycle occupy a lane on a highway?

    • AMD July 23, 2020 (6:10 pm)

      No, I’m pretty sure you shouldn’t ride your bike on the highway for safety reasons…  Glad we cleared that up?

    • Boyd Ellison July 27, 2020 (9:22 am)

      Talk about discrimination and motorcycle profiling that I’ve ever seen !!!!

  • Spooled July 23, 2020 (3:26 pm)

    “While a motorcycle is physically smaller than a car, they still require
    roughly the same amount of room on all sides to travel safely.”

    Only in the U.S. they do.  These traffic engineers would be horrified if they saw how densely motorcycles integrate with cars and urban traffic in other places.   Let  use them use the bloody bridge.

  • Sick and tired of the bs July 23, 2020 (3:31 pm)

    Sounds like just more government over reach

    • andrew July 24, 2020 (7:08 am)

      how dare they manage a bridge they built.

  • Carr July 23, 2020 (3:35 pm)

    Simple, just let us filter to the front while stopped at a red light, just like they do in the rest of the world    

    • R2 July 23, 2020 (4:00 pm)

      I wholeheartedly agree! 

    • Steve M. July 23, 2020 (8:54 pm)

      This. Every reason they gave for not allowing motorcycles would be solved by allowing legalized lane filtering/splitting.

  • Michael July 23, 2020 (3:55 pm)

    Why are we so brain dead about motorcycles in this country?  We have a massive traffic problem in a modestly sized city because nobody understands how motorcycles work.  Go to Taipei and look around.  Lane filtering is common because it solves the congestion problem at traffic lights.  Just let the bikes all move to the front because they are occupying space your car can’t and that means *everyone* gets where they are going faster.  It allows single travelers to use roads *without* all the above listed problems.  If our traffic laws weren’t so backwards and hostile to motorcyclists it would be better for *everyone* because there would be less cars on the road and less congestion.We can’t use motorcycles and scooters effectively but for some reason it’s totally ok to ride an electric moped on bike paths.  It makes no sense.

  • Jon Wright July 23, 2020 (4:15 pm)

    I have an M3 and SDOT’s decision is perfectly logical to me, nothing “crazy” about it. Riding a motorcycle versus driving a single-occupancy vehicle has many personal and societal benefits. But the problem with the low bridge isn’t that the average MPG of vehicles crossing it is too high, the problem is that the number of vehicles that can drive across is limited. For those purposes, a motorcycle is equivalent to a car. Not sure why you are dragging bicycles into this, the  analogy attempted is completely irrelevant. Bottom line is there are too many people with motor vehicles wanting to use the lower bridge and we have to restrict its use for the Greater Good. Everyone has a sad story (Doctor appointments! Essential worker! On-call! And now motorcycle!) but that doesn’t change that use of the low bridge has to be severely rationed right now.

    • Michael July 23, 2020 (5:01 pm)

      No idea what an M3 has to do with anything.  That’s a regular car last time I checked.The bicycle comparison is pretty clearly spelled out so if you don’t get it that’s because you aren’t trying.SDOT likes to pretend they care about motorcyclist safety but they really don’t.  They prefer we all sit in traffic like a car where we can get obliterated by someone on their cell phone.  Lane filtering and splitting would improve both safety and traffic flow.

  • Wavy David July 23, 2020 (5:20 pm)

    Uhg. Where to begin with SDOT’s facile excuses. Motorcyclists are a vast minority of vehicles and are up against a great deal of bias and misinformation like this. Notice SDOT’s strategic use of the word “roughly” in that motorcycles use “roughly the same amount of room” as cars and trucks. Their statement hinges on a disingenuous use of the ill-defined term “roughly” to misinform the public. Motorcycles are in fact more space and fuel efficient than cars. Ant amelioration of traffic problems must involve the increased use of them.   What they say about motorcycles being able to conceivably ride side-by-side is equally deceptive. Motorcycles ride staggered, on different sides of a lane, the front wheel well back from the rear of the other. Be this as it may, to say that this condensed and efficient method of traveling would have zero effect on traffic because motorcycles are SUCH a minority is ridiculous; if motorcycles could take the lower bridge there would be far more motorcycle density on the bridge, and therefore much more space and load savings for traffic overall. I could go on, but since the majority of folks don’t have the foggiest idea of what motorcycling really entails — let alone how time, fuel, and space efficient motorcycles are — SDOT’s lazy excuse-making to will carry the day. SDOT, the ones who completely blew construction of the West Seattle Bridge: I guess we should all trust them to know what’s what.

  • Brad July 23, 2020 (5:34 pm)

    I’m from Portland, this isn’t really my fight, but there’s a severe logic gap here. If my motorcycle effectively takes the same roadspace as a car, then it doesn’t matter which vehicle I cross the bridge in, I am effectively taking up the same space. If it’s an argument about differential in vehicle acceleration disrupting the movement of the traffic snake, then it’s an argument for lane filtering. Allowing the motorcycle to filter to the front takes their acceleration differential out of the equation, and allows the cars behind them to sit more compactly. When traffic flows, the motorcycles can accelerate through the blockage faster, apparently, and won’t be in the way of the cars.

    • andrew July 24, 2020 (7:22 am)

      If my motorcycle effectively takes the same roadspace as a car, then it doesn’t matter which vehicle I cross the bridge in

      Yep, that’s exactly the case SDOT is making. Right now the bridge is closed to all non-transit, freight and emergency access during most of the day. So SDOT is treating motorcycles just like other cars. As far as traffic flows, blockages, lane splitting: this is a two lane bridge. Passing would need to be done on the right in the shoulder, or while crossing a double yellow line (dealing with oncoming traffic, and oncoming motorcycles).  So lane splitting, by itself, wouldn’t help alleviate traffic congestion. The only situation where congestion could be helped would be if there was a dedicated ‘bike box’ for motorcycles near where the bridge opens.  It could potentially work, but I suspect that drivers would treat that as inconsistently as they do other bike boxes, and it would only be useful for the few moments while the bridge is open.

  • Mj July 23, 2020 (5:37 pm)

    Motorcycles are allowed to use HOV lanes, SDoT staff need to get some real engineers on staff again.  There simply are not that many motoryclists and they should be allowed to use the bridge.  This is really low hanging fruit for any competent engineer to figure out!

  • GAM July 23, 2020 (6:55 pm)

    Is there an appeal process to challenge this decision?     0.6% of commuters commute by motorcycle according to the 2016 Commute Seattle Survey.   Congestion is not going to be an issue with so few riders even if you quadruple the number of riders.    “We also have safety concerns about motorcycles travelling next to large trucks and buses in stop-and-go conditions, especially because congestion would likely increase considerably if more motorcycles took this route.”     Thank you for your concern but motorcycle riders know all about the dangers,  ride in stop and go traffic all the time,  and there is no getting around riding next to big trucks.     This is why riders get special training or take additional tests to get the motorcycle endorsement.  

  • pilsner July 23, 2020 (8:12 pm)

    No sympathy, most of them are a danger to themselves and those they speed around.

    • Live Free July 23, 2020 (8:46 pm)

      Not looking for sympathy from you when riding my m/c. I only ask that you don’t drive distracted and pay attention. 

      • pilsner July 24, 2020 (8:59 am)

        No problem. All I ask is that you guys don’t roll up the right lane at stop lights, blocking right turns, just so you can drag race at the greenlight. Dont weave through heavy traffic. Dont do wheelies up highland park way. All things I’ve seen. Thank you.

        • UnconsTITutitional July 24, 2020 (6:40 pm)

          Ive driven up and down highland park way multiples times a day, every day, for a decade now.I do ride and own motorcycles. I have never seen someone roll a wheelie up or down “boeing hill”. @pilsner I think you’re full of smite! And… Doodoo!

          • wendell July 25, 2020 (5:47 pm)

            The power to weight ratio of a motorcycle over a car allows it to accelerate more quickly from stop lights, it’s not a drag race, bikes move faster off the line to get out of the way – so the other below average road users can get back to texting.

            As for blocking free right turns, more cars than bikes do this.

            Weaving through traffic should be allowed when traffic is at a standstill. This works just fine in California and is safer for the rider and car driver.

            And if all you see are the wheelies up the Highland Park, you may need to look twice for bikes – most of us are avoiding getting killed on that racetrack.

    • Lisa July 24, 2020 (5:01 am)

      @pilsner – “most” is an overstatement. Most riders are safe and want to live through that day’s ride. I hope your lack of sympathy doesn’t translate into poor driving skills when motorcycles are around.

      • pilsner July 24, 2020 (11:37 am)

        I am a truck driver. Driving safe is part of my blood at this point. Im just calling it like I see it.

  • Lisa July 23, 2020 (8:23 pm)

    OMG WTF???

    What does this:

    “…a large truck or bus needs just as much room to stop safely when they
    are following a motorcycle as they do for any other kind of vehicle.”

    …have to do with whether motorcycles should be able to use the low bridge?

    Why not just ban motorcycles completely if we are following this logic.

    I thought the main reason for limiting traffic on the bridge was to allow for emergency vehicles to cross. A motorcycle might take up 1/5 the space of a car and can move over to the side of the road to allow for passing vehicles with absolutely no problem.

    Motorcycles are in stop and go traffic ALL the time in Seattle and will be stuck in even more traffic when forced to take Marginal Way/1st Ave South bridge.

    • Monica Lundberg July 23, 2020 (10:38 pm)

      I agree with Lisa. This contradicts the initial statement about giving emergency vehicles access. Motorcyclists can easily maneuver over, and as Wavy Davy describes, we don’t ride side by side. This feels really disingenuous. In addition, regarding my safety — I actually dont feel safe riding my motorcycle over all those metal grates on the First Ave Bridge! 

      • Mark47n July 24, 2020 (11:41 am)

        When I was a clubber we used to ride side by side all the time in big packs. It preserved our group integrity on the road. It didn’t mean, however, that we couldn’t get off the road and into a single file in a hurry or move off the road as a pack.The no motorcycle rule seems a bit weird but having watch the trucks around this area I get a bet nervous around them since they’re pretty reckless.I also really hate riding on those grates.

  • wetone July 23, 2020 (8:39 pm)

    What it comes down to is city of Seattle and SDOT doesn’t want privately owned fuel powered transportation modes in Seattle. They will continue making things as difficult as possible till they get wanted outcome or people vote in true  leadership.  Be interesting to measure curb to curb (width) tightest spot on bridge deck and see what fits. I am surprised more people aren’t  questioning why Port of Seattle has basically all rights to swing bridge ? their just as capable as anyone else to drive around. Why aren’t they paying a usage/maintenance fee….

    • mark47n July 24, 2020 (11:44 am)

      It’s not the Port’s prerogative to swing or not swing the bridge. The bridge is obligated to open for any and all traffic that require it whether it’s a large ship of a sailboat with a tall mast. It’s the price that’s paid for having a roadway over a navigable waterway. 

  • rpo July 23, 2020 (10:05 pm)

    I went across the low bridge on my bike yesterday at 5:30 PM. Traffic was backed up from the light at Chelan across the low bridge to 1st Avenue. There are SO many entitled people using it who are not supposed to. If there was an emergency, first responders would never get through.

  • Mj July 23, 2020 (10:42 pm)

    rpo – not true I have seen emergency vehicles navigate Montlake Boulevard, a heavily congested corridor, during the PM peak hour successfully numerous times, UW hospital is right there.  This is a red herring item.  .

    • rpo July 24, 2020 (7:06 pm)

      Explain how an emergency vehicle is going to navigate across the bridge in the same direction as stopped traffic where there’s no room for vehicles to pull over.  Montlake is 4 lanes, much shorter, and has room to navigate in the oncoming lanes when needed. The low bridge has none of those.In addition, the current traffic load leaves no room for additional vehicles without exceeding the capacity of the bridge…which is already experiencing cracking due to the loads.

  • Abyk July 23, 2020 (11:18 pm)

    Halfway joking but maybe it’s to dissuade the mass of west Seattleites who would then buy motorcycles just to use the low bridge. Believe me, my husband and I were actually thinking it. Imagine a slew of newbie riders out there!

  • Tammy Bare July 24, 2020 (2:06 am)

    In my view, the issue is volume not size..If every household in WS and Vashon had 2 motorcycles And used them each day, I can see where this could be an issue.  But we know that’s not the case. So let them use the bridge.  And if safety was the concern then I gotta believe that forcing them onto the 1st Ave S bridge which has grates is much worse. #Letmotorcyclesuselowerbridge

  • anonyme July 24, 2020 (6:57 am)

    This decision defies logic.  If the reason given is that motorcycles take up the same space as a car, then single-occupant vehicles should be banned as well.  Motorcycles are more fuel-efficient, but produce more pollutants, including carbon monoxide.  So it’s a wash.

  • Sparky July 24, 2020 (8:12 am)

    The restrictions on the low bridge are ridiculous.  They need to open that baby up and let all of us use it.  Over 90% of the time it is sitting idle except for the scofflaws.  I love how the City’s response to traffic issues always seems to be to close more streets as if that will help.  If they want to be really creative, they should figure out how to run both lanes eastbound in the mornings and westbound in the evenings making it a two-lane reversible crossing. 

  • Paul July 24, 2020 (8:34 am)

    A large motorcycle is about 8′ long. A Toyota Camry is about 16′ long. You do the math. Even with proper following distances that’s a significant savings. And at a stop light, about 4 motorcycles fit in the space of one car because they sit side by side, not end to end.  Car commuters should be all over SDOT to allow motorcycles on the low bridge—less traffic for them everywhere else! 

  • Have the developers won? July 24, 2020 (9:58 am)

    How about motorcycles use the high bridge for now while it may be structually unsafe for heavier vehicles ie; the large trucks and connexs parked on it right now. 

  • dave July 24, 2020 (5:03 pm)

    Safety? Anyone riding on two wheels nexts to cars knows what it means to stay safe and they take that risk. Motorcycles are inherently more risky than a car, but that is the rider’s choice not the city’s. Considering most cars are single occupant, this makes not a lick of sense.

  • Brian July 26, 2020 (2:59 am)

    Leave it to an engineer to f—
    up everyone’s day because it makes sense on paper. Delusional.

  • Dave E July 26, 2020 (8:55 am)

    Part of the argument SDOT uses is the size of the motorcycle compared to trucks and busses. Okay, how many times have they measured the size of a Smart Fortwo? That car looks a lot shorter than quite a few motorcycles I’ve seen and/or ridden. So should they be banned from using the low bridge at times also since they’re so small??? 

  • Motor bike Mike July 26, 2020 (1:15 pm)

    If a motorcycle takes up  the same space as a car, how about ban cars from using the low bridge? Open it to motorcycles only. I bet you would quickly see that motorcycles do not take the same space as a car based on how many more of them would be on the bridge compared to a car. 

  • Brian Zenk July 27, 2020 (12:46 pm)

    I have been riding over the lower bridge on a Honda 1982 Honda C70 scooter for 15 years two times a day. I have no problems riding around the trucks and among the cars in good or bad weather. I have accumulated over 45,000 miles of motorcycle scooter miles traveling from Holden to the Seattle Center where I’m employed. The round trip is 17 miles. Closing the lower bridge to scooter travel is a hardship.  Riding around the large trucks and buses in stop and go conditions has never been a problem. I have found the truckers to be the best drivers on the road. Most of the problems are with cars very early in the morning between five and six in the morning that speed  across the bridge doing 50 – 60 MPH.  Currently there is no way for a low cc scooter to travel into West Seattle safely because of the steep  hills on Olsen PL SW or Highland Park Way SW. These streets do not even have bike lanes of sidewalks to travel on.  I hope the DOT will reconsider the logic behind their decision.  The congestion would not increase considerably allowing motorcycles to use the lower bridge. If was lucky I might see another rider or two every other day.  Motorcyle riders always have this concern. ” We also have safety concerns about motorcycles travelling next to large trucks and buses in stop-and-go conditions, especially because congestion would likely increase considerably if more motorcycles took this route. “

  • Brian R Lange July 28, 2020 (2:06 am)

    SDOT engineers obviously haven’t looked at the studies showing that the more motorcycles are using the road, the lower the congestion levels and the shorter the overall commute times.  The 2011 Leuven study from Belgium is the most famous so I’ll link it here:

  • Derek Sanders July 28, 2020 (2:34 pm)

    Let’s take the common sense portion of our brains and throw it out the window completely…As it makes complete sense (aka “common sense”) to allow motorcycles to use the lower bridge. In fact I would even say it should be encouraged seeing that motorcycles use a significant less amount of fuel than a car or truck and the weight isn’t even a factor as far as any added wear and tear to the bridge. My truck gets 10 mpg and my motorcycle gets 50 mpg. Grant it 10 mpg is terrible fuel economy for a vehicle but even if it were able to get 20-25 mpg the difference is so great that people would be encouraged to get a motorcycle or scooter for commuting if given the opportunity to do so creating a lesser carbon footprint. Lastly, in the event a motorcycle were to break down or become disabled it is very easy to push them to a safe place off the road not causing any sort of road blockage or traffic delays and aid vehicles can easily get around a disabled motorcycle if need be.This all being said the simple fact that this makes complete common sense to allow motorcycles to use the bridge it comes as no surprise to me that the SDOT is deciding against it. I cannot fathom how we pay so much in road taxes in this county only to have the decisions made by complete morons.

  • jonathan vogel August 5, 2020 (3:49 pm)

    SDOT really isn’t thinking very clearly here.  Allow all 2 wheelers on the bridge and stop being morons.

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