This video was made by a man named Samuel Orr. Here's how he did it:
I shot this film over 4 trips to NYC 2011-2012. The time-lapse sequences you see here were made (mostly) from hundreds of thousands of still images. A Canon 7D and T3i were the main cameras, with backup from a couple of older Nikon Coolpix 5000 point and shooters. A few clips are sped-up video.
The man who made this also has a Kickstarter campaign for a film that would be a year-long time-lapse.