API for historical traffic data?

Question

Does anyone know of a public API for historical traffic data?

Some quick search queries call the Yahoo API, which offers real-time data, but I would be curious if anyone would serve historical data, i.e. what is “seriousness” (one of the attributes of the Yahoo API returns) for a given location at a given date and time.

(I'm going to guess that such a thing does not exist today, or at least there are no public options, as this will be a huge amount of data to store, but it never hurts to ask ...)

Answer 1

While yahoo has closed its apis traffic, there are a number of companies providing traffic information.

• HERE from Nokia
• Microsoft Transport API
• MapQuest Traffic API
• Predictive Traffic API from INRIX

Answer 2

These guys certainly have data, but I don't know how easy it is to access the API: http://inrix.com/developers