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Transportation Stats

Surprising Result of NYC Bike Lanes: Faster Traffic for Cars 213

A report at vox.com says that the implementation of bike lanes in traffic-heavy New York City has one possibly non-intuitive result: car traffic was sped up as a result. The bike lanes have caused the lanes for cars to be narrowed, but as a result of the street redesign to accomodate bikes, one big change has especially helped to keep cars moving forward more steadily: Although narrower streets can slow traffic, that doesn't seem to have happened here — perhaps because traffic in this area was crawling at around 11 miles per hour to begin with. Instead, the narrower lanes were capable of handling just as much traffic, and one major improvement to intersection design helped them handle more, while also letting bikes travel more safely. This improvement was something called a pocket lane for left-hand turns: a devoted turning lane at most intersections that takes the place of the parking lane, which gets cars out of the way of moving traffic when they're making a left.
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Surprising Result of NYC Bike Lanes: Faster Traffic for Cars

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  • by PhrostyMcByte ( 589271 ) <phrosty@gmail.com> on Tuesday September 09, 2014 @01:59PM (#47864055) Homepage
    But it sounds like optimizing left turns is what actually improved traffic.
    • by aardvarkjoe ( 156801 ) on Tuesday September 09, 2014 @02:07PM (#47864133)

      Exactly. It looks like the change that actually helped was that, near to intersections, they replaced a lane used for parking with a left turn lane. I don't know why anyone would be surprised that adding a traffic lane would help improve traffic flow.

      The only thing that the bike lanes apparently have to do with it is that adding bike lanes was the reason why they decided to change the lane layout.

      • Dedicated left turn lanes are incredibly important to traffic flow. The lack of left turn lanes was the most frustrating thing as a driver when I moved to Vancouver for a job. Most of the larger roads there were only two lanes wide and very few intersections had left turn lanes. So the road basically lost half its capacity any time someone had to make a left turn. I swear Vancouver's rush hour traffic would improve if they followed UPS and prohibited left turns, forcing drivers to instead make three rig
        • In Grand Rapids MI (I think it's Grand Rapids anyway) there are several intersections where left turns are not allowed. Instead, they provide dedicated turn-around spots in the middle of the block, with the intention that you drive past your turn, turn around, and then turn right.

      • by Layzej ( 1976930 )
        This same designated left turn lane came with bike lanes in Toronto and had the same effect. Prior to the bike lanes there was no dedicated parking. People would just park in the right lane - so effectively you only had one lane for cars and no room for a left turn lane. The bike lanes necessitated the designated parking which allowed for the designated turn lane. Traffic crawled before the bike lanes were implemented. It still crawls, but it crawls really fast now.
    • by amiga3D ( 567632 )

      I'm betting the bike lanes helped a lot also. Not having to follow some guy dribbling down the road at half the speed limit is nice.

      • Re: (Score:3, Informative)

        Average speed was 11mph to begin with. The bikes, able to weave between traffic at 30mph for a biker in shape, were not the limiting factor.

        I thought it was going to be more like what other cities that have implemented bike lanes and routes have seen- fewer people in cars on the road.

        • by Anonymous Coward on Tuesday September 09, 2014 @02:40PM (#47864405)

          Why are so many people delusional about cycling speeds? Nobody does 30mph on a bicycle in a city, most certainly not weaving between anything. That would be suicidal and require fantastically exceptional fitness, not just "being in shape". Most people never do more than 25mph, don't do more than 20mph on a regular basis and do less than 15mph on average - and they're still faster than a car in a crowded city.

          • Why are so many people delusional about cycling speeds?

            He's going downhill, both ways

          • All of which is greater than 11mph.....the speed of the automobile traffic in New York City.

            Having said that, I used to drive a Honda Spree. I've *clocked* bicycles doing 30 in 25mph zones.

          • by mjwx ( 966435 )

            Why are so many people delusional about cycling speeds? Nobody does 30mph on a bicycle in a city, most certainly not weaving between anything.

            30 MPH is near enough to 50 KPH (48.3 from memory). Cyclists never move this fast, not even down hill and especially in traffic. As verified by the GPS based speedometer on my dash cam, getting stuck behind a cyclist tends to peak at 20 KPH (less than 15 KPH). This is why traffic in my city moves faster in the Winter when more people are in cars instead of on their bike

            If you're a cyclist who doesn't hold up traffic we'd love to hear from you, please send a letter to:

            I'm a liar
            Top Gear
            BBC Televisio

            • by u38cg ( 607297 )
              Invariably when a motorist is "stuck" behind a cyclist they are "stuck" for a few seconds and would have to wait at the next red light anyway.
            • by Alioth ( 221270 )

              I reach at least 35 mph every day I cycle according to the Cyclemeter GPS application. It's pretty easy to reach that speed downhill.
              On the level I can sustain pretty much all day long 17-18 mph.

          • by Alioth ( 221270 )

            I'm a utility cyclist, but cyclemeter tells me I sustain about 17 or 18 mph on the flat (I live in a rural area so cars are not impeding me). I commonly hit 20mph for stretches, and there are some downhill parts of my ride where I hit 35 mph. I don't wear any lycra at all either.

    • by Anonymous Coward on Tuesday September 09, 2014 @02:24PM (#47864287)

      The addition of the left turn lane was possible only because the lane width had been reduced due to the bike lane. The thing to take home from this is that current road layouts are not optimal, and rethinking them offers improvement opportunities. That the improvements can be counter-intuitive should encourage more research into alternative layouts: If you reject change too easily, you won't find a great solution. Who would have agreed to narrower lanes if it had not been necessary in order to have a bike lane?

      • by TheCarp ( 96830 )

        This is true but, it also is a case where what works in one place may or may not work the same (or be implemented similarly) elsewhere. I have seen these exact same lanes turn into a nightmare. Not because they put traffic in the way but because they retained the left and right lanes, and just occasionally, turn the left lane into a turn only lane....so everyone who was traveling in that lane suddenly has to move over.....and few things slow drivers down like a lane merge.

      • by cusco ( 717999 )

        In 1980 the two southbound lanes of the Sunshine Skyway were knocked into Tampa Bay by a freighter. Until the new bridge was constructed the two lanes of the remaining half of the bridge every year carried more vehicles in less average time and with fewer accidents than when it was four lanes.

    • Yeah. Duh. They *added a left turn lane*, which means that they *added another lane*.

      News Flash - when you add a lane, traffics moves faster.

      • No, they didn't. The total number of lanes declined. In essence, they went from having four lanes, with no dedicated turn lane, to three lanes for most of the street, expanding to four (with one being a dedicated turn lane) at every other intersection. So, for the bulk of the street, the number of lanes declined.

        • by tlhIngan ( 30335 )

          No, they didn't. The total number of lanes declined. In essence, they went from having four lanes, with no dedicated turn lane, to three lanes for most of the street, expanding to four (with one being a dedicated turn lane) at every other intersection. So, for the bulk of the street, the number of lanes declined.

          Four lanes with no dedicated left turn lane turns into three lanes when someone wants to turn left.

          And add to that the chaos of having to do lane changes because people get stuck behind left turners

          • No, they didn't. The total number of lanes declined. In essence, they went from having four lanes, with no dedicated turn lane, to three lanes for most of the street, expanding to four (with one being a dedicated turn lane) at every other intersection. So, for the bulk of the street, the number of lanes declined.

            Four lanes with no dedicated left turn lane turns into three lanes when someone wants to turn left.

            And add to that the chaos of having to do lane changes because people get stuck behind left turners (and the corresponding people who want to turn left but were in the other lanes to avoid left turners in the previous intersection) means traffic just gets all jumbled up.

            Put in some proper traffic lights to help clear left turn lanes so people don't jam it when it fills up and spills into a straight through lane...

            Basically all that happened was in order to build a bike lane, they had to reconfigure a bunch of intersections and in so doing also happened to improve traffic flow.

            On your traffic lights point, please do remember that these left turn lanes aren't like what you're used to, if you're not a New Yorker. These are left turn lanes coming off a one way street. In Manhattan (at least) most major arteries are one way. They're not there to facilitate turning left across oncoming traffic, but rather because turners often get held up by pedestrian traffic.

    • It sounds like you've been trolled by Slashdot editors.

      Problem: how to increase traffic to the website.

      Solution: Post self-contradictory submissions so people are more likely to reply.
    • Typical click baiting. "Learn how you can turn $1 into $100M!!!"... buy a lottery ticket and pick the right numbers.
    • It sounds like the left turn lanes was part of the bike project as well, eliminating the need for bicycles to sit stationary in impatient straight-through traffic while waiting for a chance to turn left.
  • by TechyImmigrant ( 175943 ) on Tuesday September 09, 2014 @02:01PM (#47864079) Homepage Journal

    TFA implies is has nothing to do with bike lanes. The benefit comes from the improved intersection, which can happen with or without bike lanes.

    • But, which presumably wouldn't have happened without adding the bike lanes, and therefore was a happy side effect which made cyclists safer AND cars go faster.

      Everybody wins.

    • And slashdot is just the latest of hundreds if not thousands (by the time slashdot gets updated with news) of blogs and news agencies which totally reported Bike Lanes as being the cause.

    • by mjwx ( 966435 )

      TFA implies is has nothing to do with bike lanes. The benefit comes from the improved intersection, which can happen with or without bike lanes.

      The TFA not withstanding, the theory is sound.

      I live in Perth, Western Australia and roads with cycle lanes do travel faster than roads without them, even in peak hour. Not only is it faster for both motorist and cyclist, it's safer for both motorist and cyclist. Unfortunately a lot of old roads that are frequented by cyclists dont have cycle lanes. These roads are noticeably faster in the winter than the summer because the cyclists are in their cars. That's right, more cars and the traffic moves faster.

  • by Cardoor ( 3488091 ) on Tuesday September 09, 2014 @02:25PM (#47864301)
    related to citibike but a bit off topic.. if a copy tries to give you a ticket for riding in a 'non-bike-line' in NYC (as happened to me), chances are they will give you a whole song and dance: "gee whiz buddy.. sorry to have to do this, but they're cracking down. here's a ticket for $140".

    this is a police scam.

    there is no law saying a bicyclist must ride in lane in NYC.. it's only recommended but up to rider's discretion.

    I showed up to my hearing and the judge dismissed it without me saying a word (after the cop lied about how far he saw me riding of course).

    they're of course hoping you don't know the law and don't (or can't) get off from work 6 months later (when you get a hearing date) to challenge it.i wonder how many millions theyve stolen from the public this way.

    ok - that's all.
    • by jratcliffe ( 208809 ) on Tuesday September 09, 2014 @02:39PM (#47864401)

      "there is no law saying a bicyclist must ride in lane in NYC.. it's only recommended but up to rider's discretion."

      This isn't actually true. See below. If there's a bike lane, you're required to use it, unless you're making a turn, or are reasonably trying to avoid conditions. Reasonably is the key word here. Reasonably means "what a typical person in that situation would do," the rider doesn't get to define reasonably based on his/her own standards. Clearly, if there's a car parked in the bike lane, it's reasonable to go around it. If you're still not in the bike lane two blocks later, that's going to be hard to claim.

      (p) Bicycles. (1) Bicycle riders to use bicycle lanes. Whenever a usable path or lane for bicycles has been provided, bicycle riders shall use such path or lane only except under any of the following situations:
              (i) When preparing for a turn at an intersection or into a private road or driveway.
              (ii) When reasonably necessary to avoid conditions (including but not limited to, fixed or moving objects, motor vehicles, bicycles, pedestrians, pushcarts, animals, surface hazards) that make it unsafe to continue within such bicycle path or lane.

      http://rules.cityofnewyork.us/... [cityofnewyork.us]

      • well, im sure glad i didn't bring you as my attorney to correct the judge when he ruled in my favor. point is, there IS ambiguity, and cops ARE using it as a means to generate extra revenue. Don't roll over and pay if you get ticketed and can afford to fight.

        decent article on it: http://www.wnyc.org/story/2842... [wnyc.org]
        • You're on a bike, a cop yells 'halt', and you halt? What is wrong with you? God damn law abider.

        • by jratcliffe ( 208809 ) on Tuesday September 09, 2014 @03:08PM (#47864699)

          Hey, it's a defense, don't get me wrong, but your categorical statement that there isn't a law requiring you to ride in the bike line was just wrong, and bad advice for other riders. You can get ticketed for riding outside the bike line, and then it's incumbent on you to make the argument that you had reasonable grounds to be outside the lane. In your case, the judge was very friendly - not all are.

      • NY State law only requires non-motor vehicles to be as far to the right "as practicable" and has explicit provisions preventing smaller jurisdictions from restricting the freedoms of bicyclists. These segregated bike lanes are a recipe for getting plowed over by unobservant turning drivers and it isn't unusual for "practicable" to mean riding on the left side of the lane proper.

        • These segregated bike lanes are a recipe for getting plowed over by unobservant turning drivers

          If you're depending on drivers to notice you when turning, you're already dead, bike lanes or not.

      • Reasonably is the key word here. Reasonably means "what a typical person in that situation would do,"

        No, sorry, that's not what "reasonable" means as a legal term [wikipedia.org].

        It's NOT what a "typical person" or an "average person" would do. As Wikipedia explains:

        The reasonable person standard is by no means democratic in its scope; it is, contrary to popular conception, intentionally distinct from that of the "average person," who is not necessarily guaranteed to always be reasonable. The reasonable person will weigh all of the following factors before acting:

        -- the foreseeable risk of harm his actions create versus the utility of his actions;
        -- the extent of the risk so created;
        -- the likelihood such risk will actually cause harm to others;
        -- any alternatives of lesser risk, and the costs of those alternatives.

        All of those components aren't part of the strict definition, but the idea is that, legally, "reasonable" activities are those made using good judgment by a sort of "ideal" person. A "typical" or "average" person may be a jerk, for example, and act in selfish ways that could actually endanger others. (Observe traffic behavior in highly congested areas som

      • Don't be surprised that the guy you replied to doesn't know this. He's a cyclist, so as far as he's concerned he *always* has the right of way even when the law explicitly says otherwise.
  • by Anonymous Coward

    If you decrease the cross-section area while maintaining volume flow, the velocity has to increase.

    This has been another installment of Physics Applied Badly.

    • Not fluid flow. Semiconductors. Bikes are dopents. They leave openings in traffic behind them.

      • So Miller Coupling Capacitance delay implies that bikes cycling side by side go 2X slower.

      • by mjwx ( 966435 )

        Not fluid flow. Semiconductors. Bikes are dopents. They leave openings in traffic behind them.

        Not quite. To continue the electrical analogy, bikes are resistors. They slow it down, limit current.

        In traffic, there is never an opening behind a cyclist, there's normally a large line of cars trying to get around them.

  • by Ravaldy ( 2621787 ) on Tuesday September 09, 2014 @02:37PM (#47864377)

    Have roundabout been trialed in big cities? I know it doesn't apply to one way streets unless 2 of them meet.

    The small town I grew up in doubled in size since I left and they replaced 2 major intersections with roundabouts. The congestion has been reduced significantly and the police posted numbers showing a 75% reduction in accidents at those intersections in the first 5 years of implementation.

    • Roundabouts completely fail if there's lots of traffic. If one entrance has lots of traffic entering then it's likely that the entrance after it will be unable to flow into the circle at all. I've seen this in action, or should I say inaction.

      • by mjwx ( 966435 )

        Roundabouts completely fail if there's lots of traffic. If one entrance has lots of traffic entering then it's likely that the entrance after it will be unable to flow into the circle at all. I've seen this in action, or should I say inaction.

        Operative words: heavy traffic.

        Traffic lights will also cause huge tailbacks if there is enough traffic to stall a roundabout. Here you need to have a limited access road with no traffic obstructions (so basically a highway). Often, roundabouts are faster than traffic lights because they allow all four entrances and exits to be used at once. Sure you may have to slow down a little, but you dont normally need to stop compared to a traffic light where you have a 50% chance of a red light.

    • by neo-mkrey ( 948389 ) on Tuesday September 09, 2014 @03:16PM (#47864801)
      Roundabouts work. A recent Mythbusters proved it: http://www.wimp.com/testrounda... [wimp.com]
      • by u38cg ( 607297 )
        How does blowing up a roundabout prove anything? (I haven't watched Mythbusters, but I gather this is how they test everything)
    • by Layzej ( 1976930 )
      They are great for cars, but really bad for foot traffic. At a roundabout, pedestrians must wait until there is a gap in traffic to cross. There is no designated time for pedestrians to cross, like a walk signal, which means at a busy intersection you had better be quick if you want to make it through. You wouldn't want to place this anywhere people want to spend time. Only at busy intersections away from shops and destinations.
      • Huh? Roundabouts and standard crossings are equivalent when it comes to pedestrians. In both cases, you add crosswalks "circling" the roundabout or intersection, and cars must yield for pedestrians when entering and leaving the roundabout/intersection. (Example of small roundabout [findvej.dk] with pedestrian crossings and bike path.)

        If there's a lot of traffic, you add traffic lights; this, too, can be done for both roundabouts and intersections. (Example of roundabout with traffic lights [findvej.dk]; though I've personally obse

        • by Layzej ( 1976930 )
          Roundabouts with crosswalks circling them sounds ideal, but it's not how they do it where I live. As far as having traffic lights - what is the point of having a roundabout if you have traffic lights as well? That sounds like the worst of both worlds...

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality. -- Albert Einstein

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