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“We agree.”

April 11, 2014


FiveThirtyEight takes a look a bike lanes and discovers that they don’t cause traffic jams, using Prospect Park West as one of its key examples:

We can confirm our conclusions about the post-bike lane level of congestion on Prospect Park West with New York City’s Department of Transportation’s final metric. Somebody got in a car and actually drove 19 blocks down Prospect Park West, timing his or her trip during the morning and afternoon rush hours, and also during the middle of the day. The transportation department only attempted each trip once, so there’s not a lot of data for us to use in rigorous analyses. However, the city found that there was no evidence that the travel times of the trips before and after the bike lane installation were any different, and we agree.9

Interesting to note is that after the bike lane was installed “Some of the intersections were just above the level of mild congestion (V/C ratio ≥ 0.5), but not enough to affect the commute a lot.” According to the authors, “Prospect Park West was still well under capacity during rush hour.”

Of course, even if the bike lane had affected “the commute” a little, it would have been worth the trade-off. For in the “war” between bicycles and drivers,” there’s often a forgotten soldier: pedestrians.

The city’s report contains a number of other interesting statistics about the effect of the Prospect Park West bike lane. The number of cyclists using the road went up, and speeding cars, cyclists riding on the sidewalk and injury-causing accidents went down. The road diet isn’t just creating a space for bikers; it’s also making the street safer for other types of users.

A couple of things to consider in reading this story, which has ricocheted around the internet today.

  • The piece is headlined, “Bike Lanes Don’t Cause Traffic Jams If You’re Smart About Where You Build Them.” (Emphasis mine.) To the average NBBLer, that “If” is probably very loaded. As PPW opponent Norman Steisel said in 2011, “We’re not opposed to bike lanes. We’re opposed to this one and the way it was done.”
  • Evidence sways people who are inclined to be swayed by evidence. In an infamous exchange at the height of the PPW madness, DOT’s Ryan Russo offered a thorough explanation to Seniors for Safety member Lois Carswell of why the agency’s numbers on bike lane usage differed from the opponents’ own counts. Carswell’s response: “I disagree with your logic.”

Will FiveThirtyEight’s take sway anyone? Probably not, although it is a good thing that the news organization founded by the guy who correctly called the electoral results in 50 of 50 states in the 2012 presidential election has weighed in on Prospect Park West. It also means that the subject of how we get around is worthy of discussion, debate, and analysis in more than just the advocacy and policy worlds. That’s progress.

  1. April 11, 2014 2:21 pm

    “We can confirm our conclusions … with New York City’s Department of Transportation’s final metric.”

    And thus, the entire story is FLAWED.

    –Lois Carswell

  2. Brandon permalink
    April 12, 2014 8:39 am

    IIRC the largest percentage improvement in safety on PPW has actually been for people in cars, who dont crash into each other as often.

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