Because I have a one-track mind, my immediate reaction to the Vision Zero list was fear that lower speed limits on MLK would slow down the Link trains there, where traffic signals currently enforce the 35mph limit.
Luckily, that’s not the case. Sound Transit spokesman Bruce Gray says “We have no plans to change our operating speeds along MLK,” and SDOT representative Rick Sheridan says “We do not anticipate any changes to the operating speed for light rail.”
I think this is the right call. Our regional transit spine needs to be fast. Professional drivers operating in an intricately designed signaling system need not have the same safeguards as ordinary people with uneven levels of distraction. Most importantly, fast transit gets people out of cars, and that will save more lives than slowing down trains.
So for clarification, at-grade light rail is not subject to posted speed limits by the FTA? For some reason, I thought it was. These answers would seem to indicate not, even if vague.
Erp…meant: “at-grade light rail is nit subject to street speeds limits, in accordance with FTA regulations.”
Oh, mobile devices! >.<
Do you have a link to an applicable FTA regulation, perchance?
I don’t. Was just searching. Nothing is popping up so maybe it’s a non-issue, but I was pretty sure there was some directive on the matter about it having to match regular posted speeds when at-grade. If not, fantastic! I’ll let the others verify though. :)
I thought that was an ST decision–maybe an SDOT one, but local nonetheless.
Or so I recall hearing. When this was discussed at or around the line’s opening, that question came up. Perhaps for in-street rail that is mandated, but of course Link has its own reservation.
(Should have read below first–discussed at greater length there!)
Link crosses traffic lanes, but does not share them. As such, I wouldn’t expect the speed limit in the general traffic lanes to have anything to do with the speed of Link.
From what Bruce Nourish has told me, it’s not that trains cannot exceed the speed of the local arterial, but rather that the FTA requires four quadrant barriers for any level crossing with a speed of greater than 35 mph. I’ll try to find the FTA chapter and verse when I’m at a computer and not on my phone.
So, could the train go faster in Sodo?
Never mind, those aren’t four quadrant gates (but they could be).
For those who’d like to get into the 125 pages of weeds (unlike me!), here’s a research paper from the TRB on this very topic:
“Operation of Light Rail Transit through Ungated Crossings at Speeds over 35 MPH”
I thought I had heard Link isn’t subject to FTA regulations because it doesn’t share any rail with inter-state rail. This was a very deliberate decision so that the trains could be lighter/cheaper.
I’m not sure about this, but do you mean FRA not FTA?
Oh, derp. That’s probably it.
Between the station and the tight curve towards Beacon Hill, the train probably cannot go any faster through SODO than it is already going. I don’t think Link even hits 35 mph in SODO.
I meant Sodo the neighborhood, not Sodo the station, i.e., between IDS and Sodo stations and the gated crossings at Royal Brogham and Holgate.
No, it doesn’t. The posted speed limit for MAX on Interstate Avenue (and the speed at which it typically operates) is 45 mph, except entering and leaving stations.
MAX does not have four quadrant barriers. It has flashing “TRAIN” lights.
If Link is truly not subject to the same speed limit as cars, that would be great. In Germany, speed limits for trams with dedicated right of way can be much higher than cars. In some cases, up to 15 mph on larger arterials, without the requirement for crossing gates, etc.
SODO speed could be governed by distance between Royal Brougham and Lander. The train will need time to get up to running speed and then get down from it.
35 may be the top comfortable interstation speed between these two stations, so passengers don’t experience any stress from either acceleration or deceleration.
The Norristown High Speed line outside of Philadelphia was designed to run many close-spaced stops swiftly.
But I think that the reason this kind of running isn’t more common is that it puts a lot of strain on components- or requires expensive methods to prevent it.
I suspect also that the controls are as finely tuned as a skyscraper elevator. Passengers probably don’t even experience a thrill (though great to imagine a carload of Philadelphia professional people going “Wheeeeeeee…!”)
But to keep experience grown-up – or to prevent attorneys and executives from whining to make it go faster- same mechanism probably employed as one that keeps elevator passengers from floating weightless ’til they go through the bottom of the car and have to be suctioned out of the pit underneath.
Really, though, those old guys on the fold-down wood stools with Greyhound driver visor hats could throw that big brass wheel over and drop the cage out from under passengers so they really did go “Wheeeee…”
But stop at any chosen floor was smooth and accurate to a fraction of an inch. Personally, really mad computers robbed me of the last good driving job I could’ve ever gotten at this age.
Mark
Fast transit does not get nearly enough people out of cars, and it never will.
[ot]
Expanding Metro buses simply leaves you with buses stuck in congestion. Rapid Ride D is no faster than the 15 it replaced and adding more buses to either the 8 or the 44 will do nothing to speed those lines up from a walking pace.
This is an ideological statement that has no basis in facts and data. The reality is very much the opposite.
Has ST done a test of computer-controlled braking yet?
Automatic train control has very little benefits for a surface running segment like MLK.
ATC is useful when there is a capacity restraint due to limited visibility (tunnel conditions) and/or braking distances.
In tunnel conditions, there are high speeds combined with sight distances much lower than required to safely stop a train upon seeing an obstruction. Signalling systems take care of that by dividing the track into sections (blocks). If a block is occupied by a train, there is typically a buffer (one or more blocks) to the train behind it. That buffer allows the upstream train to stop in time without hitting the train in front of it. Some more advanced systems use continuous-positioning, where instead of blocks, the system knows exactly where the trains are along the tracks and derives braking distances based on that.
ATC is built on top of those signalling systems, with refinements such as acceleration/braking profiles, automatic recovery of delays, etc.
On MLK, there is no capacity constraint due to sight distances. Instead, the capacity constraint is due to level crossings. Theoretically, MLK can offer frequencies much higher than any train control system can give you, because a relatively low speed is combined with very large sight distances, allowing the trains to be operated on sight (visually, without train signalling).
This on-sight system is done in Karlsruhe, Germany with their tram-train system. Outside of the city, they use conventional signalling. Within the city on street-level, they operate on sight, just like any other tram and bus. This results in headways as short as a few seconds and in fact has caused a problem where pedestrians have a hard time crossing the street due to so many trams…
Link would benefit from ATC mostly in the DSTT (once the buses are out) and north. Visibility conditions/demand on MLK don’t really justify ATC control.
Doesn’t every transit vehicle have a hundred percent electronic linkage between controller and motor?
In addition to our Automatic Train Control, only non-virtual thing about braking is the driver on the stretches where he (or she) is in control instead.
But still think it’s a good idea to have a human at the controls of the computer anywhere a human can get hit by a train with no effort on his own part.
Mark Dublin
Regarding electronic links between the controller and motors, I don’t know :) I would think that in this day and age, most likely, especially for EMUs
But to have ATC would require very robust communication between the vehicle and the infrastructure/control center itself. That’s one of the difficult parts because the entire infrastructure would have to be equipped for constant, reliable and instantaneous two-way communication between the train and the infrastructure.
It’s not just a matter of how fast to go, but also where, when, under which circumstances (is the train late or on time?), and whether it’s appropriate (is there a red signal on the track due to an unplanned incident? Or how far is the train ahead of me so I can still stop in time?), etc.
So, not just start-drive-stop, but start-drive-stop based on the conditions of the infrastructure, other vehicles and disturbances.
Being center running, I have always thought that one way to increase safety on MLK would be to have Link run at a higher speed than the outside running general traffic lanes.
Doing this would reinforce the perception in the drivers that “there might just be a big thing about to pass them on the left.” If this perception was generally held, then there would be less temptation to perform illegal left turns in front of Link, or at least less temptation to perform an illegal left turn without looking over their left shoulder first.
Ya, it is human factors, but human factors matter in transportation design..
Or, SDOT could make left turns illegal along most of the MLK segment. Are there some intersections where left turns are allowed with a green signal sign, where making three right turns gets the job done as well (if more slowly for the automobile)?
Have there been many collisions involving Link and left turning vehicles? The 3-rights alternative wouldn’t work well on southbound MLK and, if implemented northbound, the result would be lots of traffic diverted onto neighborhood streets.
Banning left turns might be more successful along Rainier Avenue, however. There aren’t many pocket lanes or dedicated left turn signals along Rainier. Left turning autos slow down buses and create a lot of dangerous lane changes by other cars that are behind the car that’s making the left turn..
I don’t see why northbound vs. southbound makes a difference. What I’m asking is are there any intersections where three rights are feasible, in at least one direction, where left turns are still allowed in that direction.
Southbound there are soem geographic barriers (like Beacon Hill) that would make 3 rights difficult. Northbound, some intersections could be converted to 3 rights, but that traffic would have to divert onto neighborhood streets.
Think of the very busy northbound left turn lane at Othello. If 3 rights were to replace 1 left at that location the traffic would have to do a loop around the Chase Bank and then merge back onto Othello westbound. Delays would be huge.
At Graham the 3 rights would involve going all the way to Orcas and circling back by Aki Kurose MS. Not a good idea.
At Orcas the 3 rights would again divert traffic onto narrow neighborhood streets (some of which don’t even have sidewalks).
At Dawson there is a street that diverges off to the right and traffic makes a left onto Dawson at that point. It’s a unique location that benefits from the diverging street and the lack of traffic on Dawson.
At Alaska the 3 rights would again divert traffic into the Rainier Vista community (and right around the Boys and Girls Club).
At Columbian Way the 3 rights would again divert traffic into the Rainier Vista community.
For turns off MLK southbound it’s pretty much the same story. Rinse/Repeat.
At intersections like Othello, I think switching to “three rights” would involve actually modifying the local street network to support it. Today the local streets are designed to eliminate cut-through traffic and “three rights”-type maneuvers. Changes would be physically possible (i.e. connect 42nd Ave S to Othello for right turns only, remove parking on the blocks of Holly Park Drive and 39th that would be used for the SB-to-EB turn and paint in a centerline), but would be vigorously opposed by people living on those streets. Another obstacle is that the blocks that could be used for these types of maneuvers are bigger than would be ideal.
A couple prototypical “three rights”-type roads are Sunset Boulevard and 19th Ave in San Francisco. The street network there is tighter and more regular than in the area around MLK (we don’t seem to have any interest in doing that), and the side streets are wider. There are parts of Aurora south of Green Lake where I wish you could do “three rights” (say, EB 46th to NB Aurora), but interchanges force you pretty far out of the way, without actually supporting the maneuver themselves. North of Green Lake it would be pretty easy to do this, physically, and it might speed up some intersections that lose a lot of time to left-turn phases. But it would increase right-turn volume in an area where bus lanes are on the right, so I’m not sure it’s a good idea. Also, of course, people living on the side streets that would have to take on extra traffic would oppose it.
It seems like you’re essentially suggesting jughandles (I’m from NJ – home of the jughandle so I’m used to many roads not allowing left turns at all). It works in suburban areas where there’s space to build the jughandle. I don’t know how feasible it would be along MLK
There was a big outcry about eliminating most of the left turns when Link was put in. I’m sure people would not be happy about removing the remaining left turns.
@Larry: Not really like jughandles — again, look at 19th Ave or Sunset Boulevard in SF, and note that direct left turns off those roads are rarely allowed, even at signalized intersections.
As long as people obey the traffic signals, I don’t think removing the remaining left turns is necessary.
Could’t you just ditch the guardrails and put in heavy duty automatic rising bollards? Ain’t no way people driving will get through that…
Maybe we don’t have to install bollards, but merely line the trackway with poles that look like bollards, spaced to not allow Car2Goes to get through, with sensors between each adjoining poll to detect if someone is entering the trackway, and alert oncoming train operators of the fact.
There’s some sort of federal highway rule against doing that on public roads. It comes up every time there is a wrong-way driver collision on a freeway around here.
First there comes a demand that someone install directional tire shredders on freeway ramps so it is harder for those that do this to get going the wrong direction.
Second comes the response from the highway department saying that they are not allowed to put those on public roads due to a federal prohibition against solid obstructions in traffic lanes.
Running twice as many trains would make people more aware of the trains …
Also, automated trainsets would be awesome.
I don’t know about twice as many trains, but trains twice as long look more ominous. Question for the engineers: As the trainsets get larger, will it take longer (time and distance) for trains to come to an emergency stop?
I’m by no means an engineer, but I shouldn’t think so. The increased mass of the train should be compensated for by the increased number of brakes. I can’t conceptualize the difference between one four car train and two two car trains following closely.
A true emergency stop on light rail trains is very rare as it is somewhat dangerous for the passengers. There are large pads on each truck between the wheels. These are large electromagnets. When the emergency brake is turned on these magnets make the train stick to the steel rails. This also tends to throw the passengers about quite a bit.
It’s not like, say, a freight train where the brake system requires a slowly moving air signal to travel the length of the train before all of the brakes are applied. You apply the brake signal and all the cars do the same thing simultaneously.
Brock, I don’t think you will find anyplace in the world where automated trains encounter any grade-level crossings at all. Or run anyplace where intrusions are as possible as on MLK.
Mark
While I’m happy to hear that Link won’t be slowed down, if the lights continue to be timed at 35 mph for the train won’t people just continue to pace the train at 35 mph, making the new lowered speed limit mostly moot?
The train can be given a separate movement (as far as I know, it has its own signal). Theoretically, it’s entirely possible to have the through-traffic lights be “red” for cars, but “proceed” for train.
Yeah, the trains have their own signals. I live on MLK and watch many many trains go by every day. I can’t recall a single instance in which the train received a proceed signal while the MLK through lanes had red. I have seen the opposite in which the train had a stop signal but the through lanes had green.
I’m not saying that it would be impossible to re-time the lights so that the train can go 35 mph while limiting through traffic to less, only that it would be difficult to accomplish. There is already an unfortunate amount of law breaking from people impatient with the light timings (see every single car-Link collision), so I hope that whatever they do engineering-wise isn’t negated by human behavior.
Lowering the speed limit on MLK without making other geometric changes to alter design speed—i.e. the speed drivers feel they should be traveling—is working in the opposite direction of Vision Zero. You get some drivers abiding by the new limit and others who ignore the signs and focus on context (which is probably telling them to drive at more than 35 mph) leading to a wider spread of vehicular travel speeds on MLK, making the speed/position of other cars more difficult to predict for drivers and pedestrians.
+1
Yup. Simply replacing “speed limit 35” white signs with “speed limit 30” signs is unlikely to slow anybody down. Especially if the signals remain timed for 35 mph traffic.
[ot]
[response to ot]
I’m not saying Link must slow down, but the argument for slow speeds is universally applicable. Lower speeds make it is easier to stop when a potential collision is recognized. If/when collisions occur, survivability is improved. Both of those principles would still apply to Link: slower trains are easier to stop and slower trains cause less damage when hitting things.
Vision Zero means no traffic deaths or serious injuries, not just that the only victims are people (and their unfortunate passengers) who “deserved it’ because they messed up. The goal isn’t “zero deaths caused by bad traffic design & engineering,” it is zero, period. Whether this goal is actually attainable, I have my doubts. People do a lot of stupid stuff.
If Seattle is really going to embrace Vision Zero, we have other awkward things to figure out besides Link speed limits. What about bike tires getting stuck in streetcar tracks? Higher-speed cyclists mixing with pedestrians? Drunk pedestrians wandering into the street? Those are all situations that have caused traffic-related deaths or serious injuries, not necessarily in Seattle yet, but the risks are still present.
+1
Seattle can’t even afford to keep the current crosswalks clearly painted/marked.
Corralling the herds of the entitled in their $35K+ race cars is another matter entirely.
Vision Zero is going to be just that, a Vision.
At least 70 years ago, every locomotive and streetcar had what looked like a grated snowplow ahead of the front wheels. It was called a “Cowcatcher.”
Hamburger preventer or first-line motor-filter would have been more accurate, but the Interurbans often had a hundred percent rural clientele. Passenger cars with a large baggage and freight door often carried cans of milk, and other dairy and other agricultural products.
On city streetcars, a mechanism had been invented that slung a metal basket under the leading bumper, so that if a two legged pedestrian ended up at wheel-level, the basket would scoop him up, and his weight would simultaneously trigger a linking to the brakes.
Maybe modern machinery could include a flatcar at the front of every train with a sloped plate dropped by a sensor to scoop up car, bicycle, or person before they get hit, and roll them harmlessly against a cushion on the trailer.
To be deposited at the next stop, or if the people were comfortable where they were, just take them as far as they wanted to go if there was room. If demand exceeded space- line could be shut down ’til LCC hacked into Social Media and got the “Lie on the Tracks Flash Mob” called off.
Zero casualties. And declining sleep deprivation. And awesome way-cool video for YouTube!
MD
Bike tires? Seattle is really lucky! Any cyclist with problem negotiating street rail should just be able to ask Emergency Response for lift to the airport- or maybe a LINK ride with an ORCA card loaded with a pass- and ticket to Europe.
Where European Union Bike Club President will send him out for a month’s intensive training. Considering hospital bills, litigation, and paperwork, transit could afford a first-class ticket. And a bunk at a really good hostel.
Because, really, the world has well-known techniques for bringing tire in the rail incidents to Zero.
MD
And BTW, Alex, in the speed to-damage-calculation for a train-car, or train-pedestrian collision, I don’t think there’s a micrometer or a mortician’s probe that can measure the difference between train casualties from speed 35 to 20.
Also, where cross-traffic is common, motorists get impatient at being held by a train in sight but taking too long to reach them, and cross the tracks against signal. Last violator off the line pays for hesitating.
And in addition, a fast train- or bus- generally gives a smoother ride than a fast one. And a hard brake at 5 mph will throw more standing passengers down than same brake at 30. Physics, “Inertia of Motion”.
To get a stopped vehicle into motion requires much more power than keeping it motion- reason for first gear. But force needed to take 5mph to a dead stop delivers a shock to everybody aboard.
So precisely because full brakes applied at 30 take longer to stop the train, deceleration is smoother and safer aboard the vehicle. But distressing enough LINK rules discourage practice. Causes flat spots in wheels, too.
In front of it? Person or vehicle, weight comparison with train gives same results at any speed. So should probably be a blood-red column on the balance sheet for decision on grade separation or not.
Mark
I know that more than one first-line LINK crewman reads this blog. I believe that the body design of LINK cars greatly limits fatalities in any collision.
On every other light rail system I’ve observed, a coupler sticks out the front and the rear of every train- a battering ram that could likely breech a castle gate.
The bumpers of LINK cars have “visors” that cover couplers, shaped so that as much as possible the train will push anything, or anyone on the track out of the way.
Stats might be good here about vehicle damage and personal injury from LINK collisions. Which, considering operating conditions and remaining public unfamiliarity, seem to be fairly few.
And incidentally, with this country’s number of people imprisoned, and thrown out of school for minor drug law violations, the term Zero out of the mouth of a politician is one no scientist or statistician will apply to the real world.
And for any moving part, the closer to zero-tolerance-which itself is impossible-the more likely something running at high speed will break with considerable damage.
Mark Dublin
I believe this was designed at Houston Metro as a response to the casualties from car vs. LRV collisions where much of the damage was attributed to the coupler.
Bumper covers on our Kinkyshario LRVs hide a stowed coupler folded in half and locked in nearly a ‘V’ shape behind the cover.
Regardless of what Link CAN do, here is what it does from someone who drives next to it, lives next to it, and rides it regularly: It goes 35MPH, the posted limit. When I match speed with the train going down MLK, we’re both doing 35, the posted limit. Generally, the flow of traffic is slightly FASTER than the train, but that’s mostly because drivers expect to speed wherever they go in the city.
Post 30MPH, cars do 35. Post 35, we do 40. Post 60, we do 65-70. We speed. It’s what we do, reliably, everywhere. The train speeding is the LAST thing we should be worrying about. But it’s a nice distraction from focusing on the hard truth that the most dangerous thing on our roads is us in our cars, which is an unpleasant thing to think about.
If you have ever used a speedometer app on your phone you’d see that link never goes faster than about 30 M.P.H.
Speedometer apps on phones aren’t particularly precise.
Link takes a scheduled 38 minutes to travel its length of 15.6 miles. That’s an average of 24.6 MPH. There is no way it averages nearly 25 MPH yet never exceeds 30 MPH between stations.
It goes a full 55 between Tukwila and Rainier Beach, hits 35 at least once between every Rainier Valley station, and briefly hits 35 between Stadium and Sodo. The 25mph average is faster than any non-express Metro bus, but slower than many ST Express routes.
That includes being stopped at stations. You don’t say a car is “going 25” when it stops at stoplights but in between it’s doing 35, you say it’s “going 35”. Why should trains and buses be different? I’ve heard people say the average speed of trolleybuses is 12 mph, and that makes them sound unbelievably slow and much worse than cars, and is probably part of the reason why so many people drive. But when they’re moving, they’re moving at the same speed as cars.
Elevate link south of Mount Baker.
If we never LINK is never going to get an express route to Sea-Tac Airport, like Airport Way past Boeing Field elevating MLK tracks to join structure at Boeing Access should be done.
At the very least, all existing street-level car crossings should be eliminated- except at major arterials line Othello, where intersections should be “undercut”, which may require platforms be dropped to new track level.
The lids carrying the cross-streets can contain U-turn lanes.
If we’re going to build a separate express line, present MKL trackway is fairly common world-wide for local and mid-range service.
But as soon as possible, no one should have to sweat missing a flight on an airport line.
Also- complete elimination of any rubber tires across tracks should bring collision numbers much closer to zero than they are now.
Mark Dublin
In the abstract, I support this.
In the current world of limited resources, I oppose investing more resources in this line until other neighborhoods in the subareas under consideration have at least MLK-level service. (The one exception is if it allows Link to go to automated operation; I don’t foresee that in the near future.)
Mark, that’s the case already. The major arterials have signals, no other streets go through. Which grade crossings would you eliminate? And how would you justify further erosion of the local street network?
It’s not possible to do. The supports required are wider than the separation between the tracks and there’s no room for it alongside the street. Link on MLK will either be in a tunnel or surface, forever.
“for them alongside the street”. Apologies for the bad grammar.
Late apologies to Alex: In the hands of a good driver, a fast ride is generally smoother than a SLOW one. Any other kind of ride at any speed is generally re-instructable.
Of course, if you’ve got a plane to catch, banging your head against the wall gives same sensation as a rough ride.
MD
Al, I’m thinking of the ones at Columbia City, Othello, and Rainier Beach. Where instead of blocking the cross-streets, I’d put them on lids above the undercuts for the tracks. Which should definitely make these arterials faster and safer, and also provide U-turn space.
For pre-LINK MLK, for most of the day, traffic itself made it just about impossible to take any unsignalled side street all the way across the arterial.
Better example, incidentally, for the “erosion” analogy. My undercut plan would definitely improve the three large intersections that were the only usable all-day crossings before.
Given former situation, I’d compare system I’m proposing to classic erosion control: control the traffic flow and channel it, to keep it from eating away any amount of the neighborhood.
Mark
Right, you mentioned grade-separating the “major” crossings near stations (which encompass 5 intersections — Alaska, Edmonds, Myrtle, Othello, and Henderson), but then you also talked about “eliminating” the others. There are a few more ways across along MLK than that — and it’s a good thing! Would you eliminate crosswalks at Hudson, Raymond, Morgan, Willow, Holden, Elmgrove, Thistle, and Trenton? Signalized intersections at Dawson, Brandon, Orcas, Graham, Holly, Webster, Kenyon, Cloverdale, Merton, and Norfolk?
Seriously, three ways across MLK all the way from Colombia City to Rainier Beach? That’s about as many as there are ways across I-5 over a similar distance (say, Lucille to Ryan Way). Now, the I-5 crossings are bleaker to walk and more badly spaced, but this would put MLK in I-5’s league as a barrier to east-west travel in south Seattle. As if we needed another one of those.
The freeway is about twice as wide, and the nearest homes and businesses are set further back on either side, and the exit ramps are dead space. So freeways are much larger barriers than MLK is, it takes longer to cross them, and the space is completely desolate and depressing. See I-5 between 90th and 120th for instance. MLK is practically a pedestrian urban neighborhood compared to that.
Someone suggested that earlier: put the entire track in a ditch and the cross streets over it. A poor man’s tunnel. We should do it. Although I wonder about the visual impact of a ditch along the middle of the street.
If it is tunneled, either by cut-and-cover as you suggest (no “ditch” would be allowed) or boring, MLK could then be six lanes, removing the resistance to a Rainier “complete street” treatment.
The ditch is called retained cut-fill, and part of East Link will have it. Why is it not allowed in MLK? (By which I assume you mean not just neighborhood opposition but illegal.)
It will slow down Metro Route 8.