So, a number of other states have indicated in the wiki that they base the Waze road type (Major/Minor Highway, Primary Street, etc.) on their state DOT functional classification maps. DDOT has one of these, available at http://www.dc.gov/DC/DDOT/About+DDOT/Ma ... cation+Map.

I've tried redesignating some roads in Waze based on the map, but now I'm wondering if others agree with this approach. I notice that DDOT says on http://www.dc.gov/DC/DDOT/About+DDOT/Maps that "The Functional Classification System is used to identify roads, streets, and highways that are eligible for federal funds." It's always a safe bet when dealing with bureaucracies that, when they say information is used for a particular purpose, they are implicitly saying you can't rely on it for any other purpose not specified. DC may, for example, have "upgraded" some roads on paper so that they could get more federal money for them, even though the pavement on the ground doesn't justify it. (I also noticed one glaring anomaly -- Klingle Rd beneath Connecticut Avenue is shown as a collector road, even though it actually hasn't been open to traffic for over 20 years!)

Assuming we did want to rely on this map for guidance, we would have to decide which Waze road types should correspond to each functional classification. Most of them are easy, but I am undecided about "Minor Arterials" --

Interstate -> Freeway
Other Freeway and Expressway -> Freeway if it's an actual freeway, otherwise Major Highway
Principal Arterial -> Minor Highway
Minor Arterial -> Minor Highway or Primary Street?
Collector -> Primary Street
Local -> Street

Any comments, either on whether to rely on the map at all, or on how to treat minor arterials?