[Talk-us] United States Roadway Classification Guidelines

McGuire, Matthew Matt.McGuire at metc.state.mn.us
Thu Jul 29 14:40:36 BST 2010


> Can you show me an area of the US that's tagged completely objectively?

For example: Interstate 99 near Altoona, PA is coded (AFAIK appropriately) a motorway. Over the entire length of the Interstate, it looks like it serves a max average daily traffic of 37,000 vehicles per day (http://www.interstate-guide.com/i-099.html), which is equivalent to many "primary" roads.

Given this volume, it is reasonable to imagine Interstate 99 was never built. Instead there is a four lane, at-grade highway. The road would still serve the same interregional travel purpose in the area network. It could have the same traffic volume. But it wouldn't be a motorway.

Interstate 99 doesn't share other qualities of Interstates (traffic volume, Interstate Travel, connecting large cities) Therefore, the current classification of motorway is based on the physical quality of the road.

I've also been on ridiculously under-designed two lane roads in the Philadelphia and other Northeastern suburbs that carry large loads of commuter traffic. They function as primary or secondary roads, but they aren't built like the ones in my area and should not be classified the same way. If they code it as such, it will only serve to alienate visitors.

This is the North Bethlehem Pike north of Philadelphia. http://www.openstreetmap.org/?way=12336821 It is coded as a primary road.

This is Bass Lake Road west of Minneapolis. http://www.openstreetmap.org/?way=41442915 It is coded as secondary.

I'll let you dig up what the roads look like with whatever tools you're comfortable with. But the way it looks to me is that functionally, they are probably both accurate. Physically, the secondary road is a much more robust road.

These differences are reflective of regional differences, and I did not need to spend much time looking for them. If they are all coded by relative local function, we whitewash regional differences - the interesting (useful, if that's a requirement) bits to me.





More information about the Talk-us mailing list