Does anyone know of a public API for historical traffic data?
Some quick googling pulls up an API from Yahoo which offers real-time data, but I'd be curious if anyone hosts a service for historical data - i.e., what was the "severity" (one of the attributes the Yahoo API returns) for a given location at a given date and time.
(I'm going to guess that such a thing doesn't exist today, or at least no public options, as this would be an immense amount of data to store, but it never hurts to ask...)