Hi mdroads --
I'm not sure whether this is the best place to contact you, but I wanted to let you know that I'm tentatively planning a mapping party for Saturday, July 12, starting in or near Patterson Park, depending on weather and interest from the community.
This was originally going to be a bar crawl, but then I realized that it probably wasn't smart to have a bunch of random people drunkenly stumbling around the less-documented parts of Baltimore. So think of it as more of a picnic. (This is also a good time to mention that this event is in no way affiliated with my employer -- it's just for fun.)
If you're interested, drop me a line, and I'll give you more details as the date approaches.
Please feel free to pass this along to others. I'm at firstname.lastname@example.org.
National Highway System and usage of Trunk classification in the US
One parameter that could be useful in determining trunk status is whether or not the road is included in the National Highway System. The NHS replaced the old Federal Aid Primary and Secondary road classifcations. Interstates are in the NHS by default nationwide, as are most non-Interstate motorways and major highways that are not in close proximity to an Interstate. The route can be US, state, or even an unnumbered city street, if the corridor they serve are deemed of sufficient importance. An NHS route doesn't even have to be dual carriageway, but only serve as the primary route in its corridor, thus likely to be handling above average or even Interstate-level traffic loads.
It seems the closest way to adapt the rigid British classification system and its colors (where the M-A-B(T) classifications decide it) to the less rigid US road hierarchy (I-US-State can all be a motorway; the only firm rule is that Interstates must be one), and show the relationships between the Interstates and these major routes. In my experience, a lot of the routes where it's a toss-up between motorway-trunk (my local example would be MD 90), are in the NHS. --Mdroads 3:30, 22 July 2010 (UTC)