No, Traffic Congestion Is Not “Self-Correcting”

It’s true that drivers going into congested areas have learned to anticipate that other cars on the road will slow them down. Yet drivers are largely unaware how much their trips will slow down traffic at large.

Photo: Timothy A. Clary/AFP/Getty Images via Wikimedia Commons
Photo: Timothy A. Clary/AFP/Getty Images via Wikimedia Commons

Monday’s City Council transportation committee hearing was notable not just for City Hall’s dismissal of Move NY’s new home-rule congestion-pricing plan but also for the weak tea served up by city transportation officials.

Their testimony was long on slippery promises like creating “a culture of compliance on placards” and “a comprehensive plan to better manage curb space,” and woefully short on action. “Tinkering around the edges” is how Council Member Corey Johnson characterized the administration’s plans.

What stood out for me, though, beyond DOT Commissioner Polly Trottenberg’s rote rejection of the Move NY initiative, was her assertion that “economic theory tells us that congestion is self-correcting.”

Here’s the context:

Council Member Steve Levin: Is congestion getting worse? Does it ever get better?

Commissioner Trottenberg: Taxi data shows CBD travel speeds worsening from 2010 to 2016, from 9.5 mph to 8.0. Congestion is tied to the economy. When I lived in Park Slope in the early eighties, congestion wasn’t as bad, I could find a parking space. [But] economic theory tells us that congestion is self-correcting. People will use other means if it gets bad enough. But we have to provide the other means.

Calling congestion “self-correcting” is a convenient way to steer the subject away from congestion pricing. The argument is that drivers can bail when congestion “gets bad enough.” Problem solved — without collective (governmental) action requiring political leadership.

Let’s unpack that. It’s true that drivers going into congested areas have learned to anticipate that other cars on the road — i.e. “traffic” — will slow them down. Yet drivers are largely unaware how much their trips will slow down traffic at large. Indeed, we don’t find drivers pondering the time their trips take away from others on the road, since they aren’t charged for taking it.

To be sure, when traffic is light, those “time costs” tend to be trivial. My trip hardly slows down traffic, and there are so few other vehicles that any delays due to my driving won’t amount to much. But in the heavy traffic conditions that typify NYC streets — especially in and around the Manhattan Central Business District — those delay costs can be substantial.

W Sachs graphic _ 4 Nov 2015

What economic theory actually says about traffic congestion, then, is that without a congestion charge, the delays my trip causes others are externalized. I impose them but I don’t pay for them. And since I don’t pay for them, I’m more likely to drive in crowded traffic and thus contribute to congestion. The same goes for everyone else using (or considering use of) the roads. Together, we’re incentivized to drive more and, thus, take more time from each other collectively than we stand to gain individually by taking the car.

This simple yet profound insight distills the “problem” of traffic congestion to its essence. I came across it in clarion-clear language 25 years ago in a book chronicling German resistance to motorized transport in the early 1900s, For Love of the Automobile, by the cultural historian Wolfgang Sachs. Fellow activist Steve O’Neill turned it into the above graphic, which I’ve used in my traffic-pricing talks ever since.

Why dwell on this? After all, Trottenberg was probably just toeing City Hall’s line at the council hearing: Congestion pricing is nice in London and Stockholm but we’ll get by without it here in New York.

Here’s why: The congestion antidotes the administration presented to the council are fated to fail, for the most part. Not only are they small bore (ferries) or costly (subsidizing night-time freight delivery; ferries). More fundamentally, unless they’re back-stopped by a congestion price, any space on the road they free up will soon be filled by new trips made by opportunistic drivers.

Traffic does seek its own level, but that level is determined by whether and what we charge to use the roads. No matter what we do with signals and enforcement, and even with transit, we won’t keep the street space we think we’ll gain unless we charge vehicles for occupying it.

  • JK

    Simple answer: No, congestion is not “self correcting” and no, it does not get better. See west bound Canal Street on any late Friday afternoon. Traffic barely moves and it takes more than 90 minutes to travel the six miles from the Brooklyn side of the Manhattan Bridge to NJ via Canal and the Holland Tunnel. I work near Canal, and many times I’ve gone out on an errand and returned to see the same truck sitting in the same place for more than ten minutes. It has been like this for many years. BQE, Major Deegan, you name it, there are always huge peak hour delays on all of the major highways and crossings in NYC — even when traffic is flowing in Midtown.

    BTW, NYC is also failing on small bore traffic control. Double parking is rampant throughout the city because curbside prices are far too low, not enough space is set aside for commercial vehicles and in many areas of the city (see Manhattan North of 116th Street) double parking is essentially legal because of non-enforcement. Basically, it’s a mess, and the City has its street management priorities exactly backwards because of local politics.

  • Have these cats stopped to think that our failing transit system is discouraging ridership and encouraging cab/rideshare/personal car use? Congestion will *not* “self-correct” – MTA’s monthly transit reports showed that, until recently, Bridges and Tunnels traffic *increased* even as subway and bus ridership slipped. It seems cats *are* willing to pay tolls if it means avoiding the constant subway delays and pokey buses.

    Given this, killing Move NY makes even less sense (not that such a move made sense to begin with)!

  • reasonableexplanation

    Regarding each additional vehicle contributing to traffic; not always! (At least, on limited access highways!)

    Check this out:

    If you drive the ‘right’ way in highway traffic, you actually make traffic better behind you. I do this myself whenever I hit slowdowns and you can actually see your lane moving smoother behind you! If this was taught in driver’s ed we might see improvements on the highways.

  • Vooch

    agreed – we should give commercial vehicles priority over private cars.

    However, the 3 MPH pace on Canal is actually a good thing. Hulking death machines can not kill at 3MPH

  • Actually, they can – avg speed 3 MPH = endless idling = pollution = asthma. Just ask anyone living near the Cross-Bronx Parking Lot!

  • Reader

    The analysis offered by our DOT commissioner here seems to boil down to “It’s so crowded, nobody goes there anymore.” It just doesn’t make any sense. Sure, some people might abandon driving in favor of other modes if traffic gets really bad, but it would have to *stay* bad or they’d just start driving again… which would just lead to traffic getting bad again. Rinse, lather, repeat.

    I feel bad for her. She’s clearly very smart and probably wants to do more to solve this problem. But without a strong mayor willing to back her up and willing to make the case for congestion pricing even if it’s an uphill climb in Albany, I suspect she winds up having to say a lot of things she herself does not believe.

  • J

    Trottenberg in a nutshell: “just toeing City Hall’s line”.

    I guess she could resign, which isn’t great option, either. JSK was smarter about things, and got Bloomberg to agree to support her vision before taking the job. Trottenberg appears to have gotten no such assurance, and sadly DeBlasio has no vision, and no guts.

  • djx

    Good point.

  • Vooch


  • JudenChino

    Killed Ray Deter and although this was in 2011, Canal St was slow then

  • Geck

    That congestion is “self-correcting” really means that cars will fill the available space until it gets so bad some people will choose not to drive — that it will reach an equilibrium of congestion. That is actually an argument for taking away driving lanes and giving them to bicycles, buses and pedestrian. If traffic will inevitably fill the available space to a level intolerable to some, we should not hesitate to make the space for motor vehicles smaller.

  • Joe R.

    I think your experience cycling may have something to do with this. The concept described is pretty much the same as the cyclist who maintains a steady speed and hits lights just as they go green while motorists continually pass him/her only to slam on the brakes and wait at the next red light. The conservation of momentum which cycling tends to encourage also seems to carry over if the same person drives. It’s also better for the vehicle and passengers to just drive at the average speed of traffic instead of rushing to fill every gap.

    Another way I’ve thought of to mitigate traffic jams is to have barriers blocking the view of opposing traffic. So many times when I’ve been riding in cars there are miles of traffic caused solely by people gawking at an incident in the other direction. Barriers which shield the view would put an end to that.

  • Exactly. Trottenberg is not an independent actor; she can go only as far as her boss, the mayor, allows her.

    The great thing about Bloomberg was that he empowered Sadik-Khan to do what she did best; and he backed her strongly against vitriolic criticism from all corners —
    including from then-Public Advocate de Blasio, who denounced Sadik-Khan as a “radical”. (Of course, Sadik-Khan was indeed a radical! But de Blasio wasn’t praising her with this term; he was lashing out as a defender of the status quo that Sadik-Khan was endeavouring to upend.)

    De Blasio has no vision on the question of livable streets that approaches that of Bloomberg. And Trottenberg has none of the freedom to act that Sadik-Khan did. So to expect substantive or even meaningful comments from her is almost unfair.

  • reasonableexplanation

    Agree on all points! It’s harder to drive at a steady speed though on account of some motorists filling the gap in front of you. It definitely takes more active concentration and planning than just keeping up with stop and go traffic, but it’s satisfying, like a game.

    The visual barrier thing works, and there are plenty of places where highway barriers are done right, even with little room. The nicest I’ve seen is dual jersey barriers separated by maybe 2 feet, filled with dirt, with local grass/flowers/weeds growing in it. Tall enough to block view of opposing traffic, and looks nice too.

  • Ryan Vitiello

    There biggest problem with NYC is it’s geography. It’s smack dab in the middle of the metro area, and there is no “going around” it. Almost ever other major city in the USA has a beltway road to bypass it. That’s not physical possible with NYC. Choking off traffic in NYC doesn’t drive traffic around, it chokes off the greater metro areas economic growth. Ironically the worst Manhattan chokes off the rest of the metro area, the more it increases property value for itself. Since it’s impossible to travel across it, it makes it more important to be based there. That’s why office space in Brooklyn it’s not leasing. Only people on long island can get to it. Anyone in CT, the rest of NY, or NJ can’t really get to it.

    If they want to fix the traffic problem in NYC they need to deal with all the through traffic that most cities can easily send around. Maybe it’s time for a NYC big dig to bury highways carrying all the through traffic. Connect the Lincoln and queens midtown tunnel with a tunnel under Manhattan. Connect the Holland tunnel, the Brooklyn battery tunnel, the Williamsburg, the Manhattan, and the Brooklyn bridge together with tunnels to get all that traffic of the surface streets. Until that traffic has elsewhere to go, it’s just going to clog up surface streets.

  • opafiets

    I’ve had to sit in that traffic many times, and it is not by choice. My car is my field office, and that is often the most direct route home. My idea for a solution, aside from trans-Hudson and trans-Manhattan commuter rail, is a massive queuing space for all the tunnel-bound traffic in the form of an underground or above-ground parking garage. Vehicles would sit there, engines off, until space opens up in the tunnel and they can proceed at a steady speed through the tunnel. At least it would remove the imposition of stacking space from all the surface streets and cut down on pollution since the cars would not need to be running while they wait for their turn in line. It would also cut down on wear and tear on cars, since they wouldn’t be sitting in stop-and-go traffic for that trip across Manhattan. It should make the streets around the tunnel entrance more amenable to walking and biking, as they wouldn’t be as filled with cars manned by drivers who are losing their sanity!

  • Elizabeth F

    No bypass roads? What about I-90/GWB/NJ Turnpike, and I-287?

    Oh yes… cross-Manhattan expressways were envisioned and planned in the 1960’s. I think most of us are glad they were never built.

  • Elizabeth F

    In Germany, they’ve institutionalized this by progressively lowering the speed limit AHEAD of congestion. The results are a higher average speed and throughput for everyone. Of course, that only works if you’re in a culture that observes speed limits.

  • Ryan Vitiello

    I 90 is a few hundred miles away and has nothing to do with NYC traffic. The only way to get to anywhere on long island is to go THROUGH NYC. There is not a single bridge in or out of long island that doesn’t go through NYC.
    The GWB/ I-95 is one of those cross Manhattan expressways you just complained we were better off not building ( it’s the only one that was built).

    The NJ turnpike dumps all its traffic into Manhattan at various points. That’s the exact opposite of a “bypass”

    The cross Manhattan expressways absolutely all should have all been built. They just shouldn’t demolish half of Manhattan to build them. They should be in tunnels like the Boston big dig. Imagine removing all that car traffic from surface streets so surface streets could be used by pedestrians, cyclists etc…

    Where the tunnels and bridges dump into Manhattan, they cause insane levels of traffic, and are the most dangerous parts of the city for pedestrians and cyclists. Moving that traffic off of surface streets would greatly improve quality of life, safety and transportation in Manhattan.

  • Elizabeth F

    Sorry, I meant I-95/GWB/NJ Turnpike. Yes, it technically goes through a bit of Manhattan. But in reality, it is a bypass around the CBDs, that part of Manhattan is functionally the outer boroughs. Quite a different story from tearing down SOHO to build a freeway.

    I-287 is a “second-ring” bypass route.

  • There’s also the Garden State Parkway. Traffic going north past New York City can, from I-95, get on Route 80 west instead of going to the George Washington Bridge. Then at Exit 62, it can get off for the Garden State Parkway going north. Then take that north for 287 and the Tappan Zee, and across Westchester to rejoin I-95.

    It’s too bad that there is no bridge from Long Island to Westchester or Connecticut; this dooms New York City to carrying all the traffic headed out to the Island.

    The idea of putting trans-Manhattan highways underground is a nice fantasy. But it would be entirely impossible in reality. First of all, there’s just too much stuff under there already; so there isn’t room enough for auto tunnels that stretch the width of Manhattan. Even if there were a way to thread a roadway around the subway tunnels, power lines, water pipes, and everything else down there (which there isn’t), the magnitude of digging that would be necessary simply could not be done, as it would entail closures of a large portion of Manhattan Island.

  • Ryan Vitiello

    I don’t think you understand what a bypass road is.
    You also can’t get from Jersey City to Brooklyn without going through Manhattan. It’s not practically possible. This is a lack of infrastructure. Most cities can simply bar this through traffic by routing traffic around their downtown. That’s simply not possible in NYC metro area. The routing you mentioned is also not legal for commercial traffic. You are only thinking of this from the perspective of passenger cars.

    The more Manhattan cuts off the rest of the metro area, the more it depressed property value and transit everywhere else, and the more it creates density and more traffic in Manhattan as businesses all try to crowd into this small central area.

  • Joe R.

    Just to sure, if we’re talking strictly an underground connection between the Holland and Lincoln Tunnels, such a tunnel could stay at the present level which both tunnels reach before climbing into Manhattan. This is under the river bed, and well under any foundations or other existing structures in Manhattan. Of course, the cost would still be huge, but it’s not really a matter of threading it through existing underground structures. You would break an opening into, say, the Lincoln Tunnel at the midway point to create a junction. One side of the junction would be the existing Lincoln Tunnel into Manhattan. The other side would be the bypass. It would be bored straight through until it hit the Holland Tunnel roughly at its lowest point.

    I know Elon Musk is working on lower cost tunneling technology for his Hyperloop project. Even if the Hyperloop is a failure, connecting the Lincoln and Holland tunnels might be a good use for it. If it’s cheap enough, I’d love for the tunnel to just continue in Queens. Build it under the existing LIE, and once completed shut down the LIE, and restore the street grid. Do the same with the other NYC expressways. While we’re at it, build some bike tunnels as well so cyclists can enjoy the advantages of no-stop travel between boroughs.

  • If it’s true that a connection between the Lincoln Tunnel and the Midtown Tunnel would go under all existing subway tunnels and other underground infrastructure, then that does simplify it quite a bit.

  • Andrew

    But before we expend scarce public resources on a highway tunnel, might they not be better spent on a subway or railroad tunnel? I don’t know the answer, but it makes no sense to spend that sort of money without even asking the question.

  • Andrew

    Trucks can skip the Garden State Parkway and hop directly onto I-287, which is in fact a bypass route of New York City.

  • Joe R.

    Depth chart for area near Manhattan:

    It looks like the rivers are 40+ feet deep where the tunnels are. The tunnels are probably at least 10 feet under the river beds, implying they are at least 60 feet below sea level at their lowest points. Not much in Manhattan is at that depth, for flooding reasons alone. Even the WTC foundations didn’t go that far below sea level. It looks to me like a bypass tunnel would be in the clear. Don’t forget if need be you could go even lower. You could drop from 60 feet below sea level to 100+ feet below to go under Manhattan.

    Of course, as Andrew mentions if we’re going to spend this kind of money, why not spend it on a much more needed railroad or subway tunnel?

  • Ryan Vitiello

    That’s great if you are going to New England. Useless if you are going to long island. Long island traffic MUST go through NYC.

  • Christina

    There’s too many cars because of Uber & Lyft. If people went back to taxis there would be less cars. I use the taxi app E-HAIL ( same convenience but real drivers.

  • Sanjeev Ramchandra

    Have you ever heard of Staten Island? From Jersey City, you can take the Bayonne Bridge to reach I-278 before crossing the Verrazano Bridge into Brooklyn. Outside of Hudson County, you can take either the Goethals Bridge or the Outerbridge Crossing to reach Staten Island before connecting to I-278 to reach Brooklyn.

  • Andrew

    Well, yes, that’s plainly obvious – the only road connections onto Long Island are through New York City. They don’t require driving through the Manhattan CBD, however.

  • Andrew

    Sounds like an incredibly expensive sort of “office.” Are you proposing that only people like yourself who make use of your proposed “office” space pay for it, or do you expect the rest of us to share in the cost? (My employer pays for the office space in which I work but doesn’t ask you to pitch in.)

  • Ryan Vitiello

    They are still overloaded urban roads that send you right through densely populated areas. That’s why most shipping companies charge a NYC/ long island surcharge. It’s significantly worse to deal with then any other city or region in the continental USA. The roads are so bad they are choking off the economy.

    NYC roads have a serious problem, yet there is no will to fix them.

  • Andrew

    It is currently cheaper to drive from Long Island to New Jersey via the Manhattan CBD than via Staten Island, and the return trip, if over one of the East River bridges, is no more expensive.

    Before burning billions and billions of dollars on tunnels under Manhattan, perhaps let’s try simply adjusting the pricing so that it’s cheaper to drive via Staten Island?

  • Ryan Vitiello

    I would total agree the tolls should be adjusted as well. Though I think New York already said they plan to do just that. They want to toll all bridges at a lower rate, and cap the max daily toll per vehicle.

  • opafiets

    I had a conversation with a guy from a company that ships a lot of nursery stock (plants and trees) into Long Island. The NYC bottleneck is a real problem for them. He told me a lot of experienced truckers won’t even do routes through the city because it is so bad and stressful. So you end up with these inexperienced guys, drivers that can’t read English well, and they end up causing accidents and going onto parkways, in turn causing MORE congestion. It is a massive negative-feedback loop. Yet another reason the Cross-harbor Tunnel is necessary, though I’m not expecting to see it in my lifetime.

  • Ryan Vitiello

    Exactly! I can tolerate driving the NYC metro areas since I grew up there and got my CDL there, but it’s an absolute nightmare. Most companies charge a surcharge for having to drive through NYC or long island because it is so bad and slow. This costs the economy billions in list productivity and reduced economic growth.

    Yes a big dig style highway system under NYC would make the Boston big dig look like pocket charge, but the list economic activity for not fixing infrastructure is astronomical. It’s only going to get worse and more expensive the longer we wait to fix it.

  • opafiets

    I really need to explain the concept more fully for it to be understood. I put together a 21 page pdf detailing it, if you’re interested. The off-street tunnel waiting areas would also function as “stations” or “collection nodes” for people looking for a ride out of Manhattan. Car commuters would sell the empty seats in their vehicles. The drivers and riders would find each other with apps like Uber Pool or Lyft line. If commuters know they can go to a point where they can get a ride under the Hudson at any time with a minimal wait, they should be more inclined to leave their cars outside of the city, reducing the traffic volume on Manhattan streets, leading to better conditions for pedestrians and bicyclists. The idea is removing the stacking space function that is imposed on the surface streets in the area of the tunnels and moving it to an underground or above-ground garage. As it is now, the “costs” of all that traffic backing up on surface streets is borne by all, residents and commuters alike. It is a matter of converting it into a less harmful form and reducing overall volume.



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