Obligatory XKCD: <a href="http://xkcd.com/1138/" rel="nofollow">http://xkcd.com/1138/</a><p>In Seattle a few intersections have been singled out as the most dangerous for cyclists because of the number of collisions involving cyclists there. Considering they are also the highest-traffic intersections for bicycles, it doesn't actually say anything about how dangerous they are per cyclist-trip.<p>Crashmapper is useless without knowing how many vehicles pass each intersection per day.
I learned that pretty much every corner has crash potential. :)<p>We ran into a similar problem at my last job. I mapped crash locations in our game to the map in which they took place. When viewed in aggregate it ended up turning into more of a map of where people tend to congregate in the game then where problem spots actually exist.
This is a good example where some color would really help.<p>There are points with the same color where their collision count is different by a factor of 10.
Comment on style: The transparency of the orange heat spots should not fall below 30% or so, even at the center. Having the heat spots opaque makes the map difficult to read.
Huh. I worked at a place that had access to data similar to this, but statewide and in a different state. I wanted to put something like this together, but i was told the data was very sensitive and that I couldn't get access to it, since knowing that some intersections are really dangerous opens up government agencies to lawsuits for not fixing them.<p>So its interesting to see this here.
Great start!<p>It would be wonderful if you could enter a time span, rather than seeing one month at a time.<p>Maybe filter by daylight/nighttime hours?
It's worth pointing out this historical context mentioned in the OP's Github:<p>> <i>Council Member Jessica Lappin got into an animated discussion with Petito over traffic crash data. When Lappin asked why NYPD is releasing data in PDF form — and only after the council adopted legislation forcing the department to do so — Petito replied that the department is "concerned with the integrity of the data itself." Petito said NYPD believes data released on a spreadsheet could be manipulated by people who want "to make a point of some sort." An incredulous Lappin assured Petito that the public only wants to analyze the data to improve safety, not use it for "evil."</i><p>This is a persistent problem in public records law: officials who are asked to provide public data in computer parsable formats but instead, deliver it as PDFs or worse, as paper printouts.<p>The reason given by the NYPD is so common a trope that it's hard to say that they're just technically slow. When you consider that the NYPD has taken strong criticism for not investigating fatal accidents seriously, it's reasonable to suspect the NYPD of actively obfuscating when they use the "oh but they'll alter the spreadsheets!"