The Where of New York City Traffic Deaths

More New Yorkers die on the streets because of traffic-related trauma than because of homicides.  Recently, these deaths have become a hot-button issue for everyone in the city, from pedestrians to politicians.  PediaCities is tackling the issue, too, using civic data to put together a map that answers a simple question: where do we get hit?

Amanda's MapBox Map

What’s going on

Not too long ago, a spate of pedestrian deaths in the five boroughs of New York City led to an outpouring of public outrage and a flurry of news coverage about traffic fatalities in the city. Public reaction to these deaths has been huge, including tearful public testimony and even a grass-roots move to post 20mph speed limits in Park Slope. News outlets including GothamistAtlantic Cities, and WNYC, as well as more traditionally traffic-focused outlets like Streetsblog and Transportation Alternatives all reported on frequent speeding and lackluster traffic enforcement practices and chronicled police and legal responses to pedestrian and cyclist deaths in the city.  Suddenly, everyone in New York was talking about the uncomfortable, often dangerous way cars interact with pedestrians and cyclists on our city’s streets.

The public mood and media coverage also coincided with increased political momentum to tackle the issue of traffic safety in the city. Mayor Elect Bill De Blasio stated he would aim to reduce traffic deaths to zero. William Bratton, De Blasio’s appointee for police commissioner, similarly stated that it’s time to take on traffic deaths in the city, as WNYC and Streetsblog have recently reported. This rhetorical direction mirrors actions in the New York City Council: City Councilmember David Greenfield introduced a bill to reduce city speed limit to 20mph via changes to the administrative code (since revised to reduce the limit to 25mph, as reported by the New York Times) and the Council unanimously approved a bill put forth by Councilmember Debi Rose that would accelerate the installation of speed humps around schools.

The New York Police Department, perhaps in response to all this public attention, conducted a “week-long pedestrian safety and awareness drive” in which they issued 4,347 moving violations summonses — presumably more than they normally do in a given week (check out the NYPD press release, if you’re so inclined.)

Where the data come in

As WNYC reported two weeks ago, two-thirds of New York City streets are within a quarter mile of a public or private school. That is, the the city council could administratively lower speed limits on those streets without approval from Albany, as suggested in the bill presented by Greenfield. WNYC made a striking pink map to illustrate just how much of the city could potentially be impacted:

WNYC School Zones

WNYC has similarly reported that the biggest threat to NYC’s school-children is cars, stating that around 1,800 schoolchildren are hit by cars each year.

These two WNYC articles got the minds here at PediaCities thinking. Why not look at the overlap between crashes and those zones?  That way, we can see how many of the collisions are in those zones and – most importantly – watch to see if these crash statistics change as New York City’s traffic laws and behaviors change!  To begin exploring this data, I put together the SchoolCrash map you saw up above, using the fine platform provided by MapBox.

Taking a closer look at this data illuminates some interesting points.  First off,  12% of all the vehicular collisions recorded during this period involved injury to pedestrians or cyclists (that’s 31,558 of 257,639 collisions, for those counting).  Of those 31,558 collisions, over 80% occurred in the school zones.  Strikingly, all of the instances of pedestrian or cyclist death recorded during these two years also took place within one of these zones.

 

Location of collisions

The NYPD data recorded contributing factors in only 66% of those crashes which involved injury or death.  Interestingly, “unsafe speed” was cited as a contributing factor in exactly zero of these crashes; instead, the most popularly cited individual factors were, in order of frequency, “Driver inexperience” (cited in 23% of crashes), “Failure to yield-right-of-way” (12%), and “Unsafe lane changing” or ‘Turning improperly” (at 4% each).  All of this points to new questions about how the NYPD attributes cause to collisions, and returns us to the question of what impact, if any, lower speed limits might have.

Causes of Collisions

A bit about the traffic crash data we used

Despite the passage of New York city’s open data laws, the New York Police Department has been reluctant to adopt an open-data ethos and has actively argued against releasing crash statistics.  To date, the department continues to release crash data once a month in the form of hack-unfriendly pdfs.  This doesn’t mean that resourceful folks haven’t managed to work with that data, though.  One resourceful folk in particular, John Krauss (whom you should follow on twitter @recessionporn) made a NYPD Crash Data Band-Aid.  This awesome tool scrapes data from the NYPD’s monthly pdf and gets it ready for use. We owe John mega-thanks for letting us (and everyone else) use this scraped data free of charge.  Thanks, John!

If you’re interested in more visualizations of NYC traffic crashes, check out Crashmapper, also by John Krauss, and/or Crashstat, by the transportation advocacy group Transportation Alternatives.  Just keep in mind that the two maps have different data behind them: Crashmapper uses data from 2011 to the present; Crashstat uses data from 1996 – 2009.

NYC’s traffic safety future

PediaCities is looking forward to tracking crash patterns and generally beefing up our transportation section.  What other traffic data would you like to see mapped?  Window tint violation summonses? Speeding violation summonses? Tickets for jaywalking (yeah, right…)?  Let us know!  We promise we’ll get back to you.

 

Amanda

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