Speed camera locations deduced from the locations of tickets listed in the NYC Department of Finance dataset of parking violations under violation code 36, "Photo School Zone Speeding Violation." (Photo tickets are, indeed, classified as parking tickets.) Reported locations can be vague, and the mapped locations are our best estimate. In some cases we combined some relatively close locations on the same stretch of road.

We deemed a camera to be "active" if it was operating for more than 10 days in a fixed location in January 2015 up to Jan. 26, 2015 which is the last day of data used. Cameras can be turned off or moved at any time, so all "active" locations are estimates.

By state law, cameras only operate near schools on school days during school hours.

Dollar values were calculated from tickets issued, which are $50 each. That doesn't account for additional fees or tickets that were dismissed or decreased.

Crash statistics calculated from NYPD collision data from September-December in both 2013 and 2014. We counted all collisions within 500 yards of our location estimations for 21 installed cameras.

Information on hand-written speeding tickets calculated from NYPD monthly citywide reports.