Building the former in an open (and maybe distributed, if I'm really hitting the pipe dream hard) fashion has always seemed like an interesting project, this di

Building the former in an open (and maybe distributed, if I'm really hitting the pipe dream hard) fashion has always seemed like an interesting project, this discussion may give me the impetus to play around with it a bit more. I never really liked the waze method of manual input, but that's a really braindead way of getting started; it seems however that you could do tricks like anomaly detection of speed of a car through an area when compared to other cars on that street/streets around it with some very hand wavy heuristics. Contributors would install the app and it'd start building a database of avg speed and variance for roads/groups of roads. Anonimization comes to mind as a concern, but since you just need to know "someone drove on that street" at some point recently I imagine there are some things you can do to reduce potential impact/aggregate, since traffic jam data gets less useful in places with less people, although that does require a large starting population, and at this point I'm rambling. The other advantage of a system like this is that it could readily be used for road discovery, frankly as someone who knows nothing about the open mapping community I always figured something like that _had_ to exist to make it more feasible.