> What's the point of having it public then? The department of transportation is already using that data for monitoring traffic so there's zero need for anyone else to replicate their work.

Personally I do find it useful to be able to glance at the NYC traffic cams as a supplement to traffic maps, not only because having an actual visual on the traffic can help me decide on a driving route better than red or green map lines or a routing algorithm I know will take me on an inferior path to “avoid” perceived traffic, but also because the cameras pick up other nearby stuff. I like to go on runs over the Brooklyn Bridge, but it’s so swarmed with tourists most of the time that I’ll check the DOT cameras so I can see if the pedestrian path is clear enough to run on without being clotheslined by a selfie stick.

I also spend a lot of time north of the city, and the state highway traffic cams are great for checking the plowing status during/after winter storms before setting off for a trip.