DOT Lays Out a Strategy to Make Left Turns Less Dangerous

Left turns accounted for 30 percent of pedestrian and cyclists fatalities in 2015. Image: DOT
Motorists tend to take left turns faster than right turns, leading to a higher rate of injuries and fatalities. Image: DOT

DOT will be ramping up the use of intersection treatments to protect pedestrians and cyclists from left-turning drivers, the agency announced today. The initiative is paired with a DOT study, “Don’t Cut Corners” [PDF], that illustrates the disproportionate danger of left turns. Mayor de Blasio had announced in January that reducing the risk of left turns would be a focus of his administration’s Vision Zero agenda this year.

Drivers turning left account for 19 percent of serious pedestrian and bicyclist injuries in New York City — three times the share caused by right turns, according to the DOT report. Motorists tend to take left turns faster than right turns, a risk that is further compounded by the vehicle’s “A-pillar” (between the windshield and the driver’s door) obscuring the driver’s vision, the pressure of both oncoming traffic and traffic behind the driver, and a greater area of exposure for pedestrians.

Based on crash reports, DOT found that injuries involving left turns typically occur when the driver turns from a minor street (usually one-way) onto a street 60 feet or wider (usually two-way).

hardenedcenterlines
The posts in this “hardened centerline” prevent left-turning drivers, like the person behind the wheel of the Lay’s van, from cutting corners and taking turns too fast. Photo: David Meyer

The study also found that seniors are more likely to be injured or killed by left-turning vehicles: The average age of victims in left-turn crashes was 67, compared to 50 for victims of right-turn crashes.

DOT also studied the effectiveness of measures like leading pedestrian intervals, left turn restrictions, left turn bays, signals that fully separate turning drivers from crossing pedestrians and cyclists, and protected bike lanes. All of these treatments have led to a reduction in injuries involving left turns, according to before-and-after analysis of 478 intersections.

leftturntable
Protected bike lanes and LPIs led to substantial reductions in fatalities and severe injuries involving left turns. Table: DOT

The de Blasio administration has rapidly expanded the use of leading pedestrian intervals (LPIs), which give pedestrians a head start to establish themselves in the crosswalk before turning motorists get a green light. In 2015, the city added 417 LPIs — up from 55 in 2014 and 13 in 2013 — and will install another 500 this year. DOT evaluated 104 intersections that received LPIs between 2003 and 2011 and found a 56 percent decline in pedestrian and bicyclist fatalities and severe injuries caused by left turns.

DOT Commissioner Polly Trottenberg unveiled the study this morning at the intersection of Lafayette Street and Kenmare Street in SoHo. On hand was Lucas Maxwell, a 9-year-old student at nearby P.S. 130 who made a video earlier this year urging DOT to make safety fixes at the location.

Since Maxwell posted the video, the intersection, which is in the top 1 percent of NYC intersections for left turn crashes, has received a number of fixes, including a “hardened centerline” on Kenmare and a 12-second head start for pedestrians crossing Lafayette, part of a “split LPI.”

Split LPIs give pedestrians the signal before motor vehicles and then flash yellow for drivers instead of giving them a steady green — a reminder to take the turn carefully. There are currently a few dozen split LPIs in the city. If they prove effective, DOT will accelerate the use of the treatment.

DOT's new treatments for left turns: "hardened centerlines" (left) and "enhanced daylighting" (left and right). Image: DOT
DOT’s new treatments for left turns: “hardened centerlines” (left) and “enhanced daylighting” (left and right). Image: DOT

Hardened centerlines are another new safety treatment that will be piloted this summer at 100 of the city’s most dangerous intersections for left turns. They consist of plastic posts on the centerline and prevent motorists from cutting corners. Another treatment that will be piloted this year, “enhanced daylighting,” uses parking restrictions and painted curb extensions protected by plastic bollards to compel motorists to take more careful turns.

  • ItsEasyBeingGreen

    Enhanced daylighting looks an awful lot like a protected intersection. https://systemicfailure.wordpress.com/2016/07/21/all-bulb-outs-should-be-designed-this-way/

  • Jeff

    I adore the “Split LPIs” used in conjunction with bike signals on protected bike lanes. 1st Ave and 61st St comes to mind. Not ideal, of course, but a huge step up from the standard “mixing zone” without this treatment.

  • I dont see anything about banning left turns. I remember in Sao paulo (or was it Santiago?) in the downtown area, left turns were banned, period. If you wanted to go that way, you made three right turns.

  • djx

    Whether you agree with DOT or not, they’re trying to be professional. Contrast that with NYPD seat-of-the-pants non-analysis: “We heard some cyclist got killed. He probably ran a light and killed himself. So we’re going to sit in our cars and ticket them cyclists”

  • Joe R.

    I totally agree that NYC should ban left turns except in places where doing so would force drivers to take a much more circuitous route than just making three rights. UPS already routes their trucks so they don’t need to make lefts. There’s no reason to continue to allow left turns in NYC for general motor traffic (we should still allow them for buses, bicycles, emergency vehicles, perhaps delivery trucks during off-peak hours).

    We could also try jug handles like NJ. I know NJ is often the butt of jokes for using jug handles, but it seems to be a better way to handle left turns.

    Traffic circles are a third option on making left turns safer.

  • c2check

    Really just interim bulb-outs.
    I would love to see them everywhereeeeee:
    they not only slow turns and provide better visibility
    but also much more room to wait on busy sidewalks
    and keep people from parking in the crosswalks!

  • Joe R.

    If we let DOT have free reign, we would probably be seeing a lot more innovation solutions. Unfortunately, we let non-experts on community boards overrule DOT, often solely for nonsense reasons like the loss of parking spots. In fact, distrust of experts is an ongoing societal problem which we need to fix if we’re ever to advance as a society: http://thefederalist.com/2014/01/17/the-death-of-expertise/

  • Note: “free rein”.

  • Taylor Sky Collins

    I wish this idea of forcing drivers to be responsible would spread to other cities. New Orleans’ DPW redesigned (ish) Decatur Street and North Peters Street (major through-routes in the French Quarter) a few years back and one of the more laudable changes they made was to narrow the two traffic lanes and stripe a buffer in the center as well as install properly-curbed pedestrian refuges at intersection crosswalks. The problem is that, as bad as you think drivers in your city are, chances are New Orleans drivers beat them hands down. People started running into the pedestrian refuges, which admittedly were simply painted yellow with no bollards or signs. After a few too many Lexuses and Mercedes had had their front suspensions and oil pans obliterated, the City bowed to the pressure and dug up the nice beefy curbs and installed shallow ramped curbs that you could drive over in a sportscar. Consequently, we now get to deal with people doing as the truck pictured:

  • rao

    The split LPI idea sounds great! Giving drivers a flashing yellow sends a clear message that they must be extra careful when turning.

  • walks bikes drives

    There is a flashing yellow on my corner. Honestly, it sends no message. When I cross as a pedestrian, drivers treat the turn as any other. When I go through it as a driver, I treat it as any other. But then again, the latter is still me behind the wheel, so I am hyper vigilant about doing it safely. The former, though, is why I stick with the statement. Adding the yellow really just gives a legal difference. It is a turn arrow, so of it were a green turn arrow, legally that means the driver has the right of way. Yellow means the pedestrian still has the right of way. But this is NYC, how many drivers here think pedestrians EVER have the right of way?

  • walks bikes drives

    But this mayor seems to be the first to overrule community boards. Finally.

  • walks bikes drives

    Jug handles take space.

  • walks bikes drives

    They exist already in a number of intersections- the pedestrian islands built into protected bike lanes.

    But is it me, or does the Amsterdam Ave bike lane look like it will not have so many concrete islands?

  • Joe R.

    Obviously there would be a limited number of places where we might use them. For NYC roundabouts probably represent a more practical way to safely allow left turns. And roundabouts will fit in existing arterial-arterial intersections quite nicely for the most part.

  • AnoNYC

    Shouldn’t there be a bollard at the inside of the box area of the crosswalk? A lot of drivers ride the crosswalk when they turn. I don’t see it in the photo.

  • Kevin Love

    Love the essay at the link. I strongly recommend it.

  • Bernard Finucane

    Median strips should extend across the crosswalk to prevent wild turns.

    https://www.google.de/maps/@51.2101272,6.8030823,3a,75y,16.44h,64.91t/data=!3m6!1e1!3m4!1sB1OScOVndbGrqvCDJQtUNA!2e0!7i13312!8i6656!6m1!1e1

    This is especially true at irregularly shaped intersections. American city planner seem to take the attitude that if the intersection is irregular, the lanes should just get wider and swallow the irregularities. In fact, drivers need more guidance at these intersections, not less.

  • Bernard Finucane

    To be fair, I doubt that truck is moving very quickly. Anyway steel postsare often more effective than curbs.

    https://www.google.de/maps/@51.2124704,6.7989432,3a,75y,260.9h,63.82t/data=!3m6!1e1!3m4!1srDvrg7qpLscP8MhX-R6IAA!2e0!7i13312!8i6656!6m1!1e1

  • Bernard Finucane
  • J

    I’d like to see the hardened centerline extend to the other side of the crosswalk as well. This would really cut down the turning radius, making it much more difficult to turn at speed and kill someone. On a 4 lane street, is there anything preventing such a design?

  • J

    Oops, looks like I repeated your idea.

  • Samuelitooooo

    I saw a couple of the enhanced daylighting treatments on specific intersections as they came in in Jamaica, and I definitely think they’re making a difference.

    I wonder why they didn’t paint it as a curb extension though. But that’s okay, I’m happy with this.

    LPIs are amazing, and I say that as a transit-using pedestrian. Now as a bike rider, I await the day I can ride through LPIs.

  • Samuelitooooo

    Its there in the photo, and judging by the two of such treatments I see regularly in my area, it’s on every application as well; the outside edge of the curve for the enhanced daylighting has plastic posts, the same thing used for the hardened centerlines.

  • In the report, DOT did not discuss split phases, the most effective way to fully protect a pedestrian crossing. They claim that the sample size was insufficient but there are studies of 77 intersections, another study was done by DOT ITSELF. And split phases are installed at every major intersections on bike lanes. So one wonders what is their motivation for not publishing the study and not including this tool ? Is it that they just do not want to install those ? And why ?

    Instead of applying this proven medicine to the problem, DOT propose to roll out an experimental medicine to the 100 sickest patients….I do not think any engineer or scientific would approve of this protocol. It will take 2 years to know how it works. I wish it works, but 100’s of live will have been unnecessarily shattered if it does not , while they could be saved.

    This may all be a matter of money .. but Once again pedestrian will not be afforded the same basic human right than drivers have had for the last 100 years : being fully protected by a signal when they cross the street. Split LPIs give you 7 seconds of protection . That is all We get for our taxes? We are and remain second class citizens and accepted road kill .

    And I will continue to look over my shoulder every time I cross the street, afraid that a car will run over me. This is not a walkable city and this is not Vision Zero. This is just faking it.

  • ItsEasyBeingGreen

    It’s not just money, think of all the parking that would have to be removed to make room for turn lanes. Won’t someone think of the parking?

  • True but DOT is already proposing to daylight intersections.. So we are half way there. And moving turning cars to a turn lane frees up more flow for the remaining cars…
    Safety + flow should trump parking..

  • neroden

    NYC has too many one-way streets for this to work sanely. Basically the left turns remaining are all ones where it’s much more complicated than “three rights”, thanks to the one-ways.

    (That’s another problem, of course… why does NYC have so many one-way streets anyway?)

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