[Talk-us] US highway classification

Nathan Mills nathan at nwacg.net
Sat May 28 03:41:34 BST 2011


 On Fri, 27 May 2011 21:26:53 -0500, John F. Eldredge wrote:

> I have driven on quite a few highways here in the USA that vary, mile
> by mile, in the number of lanes, how well they are graded, whether or
> not driveways connect directly to the highway, etc.  This usually
> reflects their having been upgraded one piece at a time.  Sections
> that pass through difficult terrain are often the last to be 
> upgraded.
> Of course, whether or not a local politician has friends or relatives
> in the road-construction business makes a difference as well.
>
> If you classify these highways according to their importance to the
> transportation grid, then long sections, with variable physical
> characteristics, will be classified the same.

 Obviously some element of judgment is required no matter what. As you 
 correctly point out, there is substantial variability in how roads are 
 built in the US. If the substandard section is small, one could perhaps 
 overlook it. If the upgraded section is small relative to the rest of 
 the highway, perhaps it should not be used in determining the 
 classification of the road. The intent here is not to classify solely on 
 physical characteristics, but there is clearly a difference in the 
 suitability of a road for long distance travel depending on whether it 
 is 2 lane or 4 lane divided, and that should be reflected on the map, 
 not just in tags.

 I wouldn't downgrade a rural Interstate from motorway just because 
 there are two driveways in three hundred miles that might see use three 
 or four times a year. Nor would I upgrade a hundred miles of US highway 
 from primary merely because of a mile of divided highway and one grade 
 separated interchange.

 Besides, if importance to the route network is the only consideration, 
 we ought not be using trunk at all or all US highways ought to be 
 classed as trunk. It seems obvious to me that neither can possibly be 
 the sole consideration.



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