I'm currently working on a small program that evaluates OpenStreetMap data to calculate how twisty or curved roads are in order to generate maps of roads that may be of interest to motorcycle riders or other driving enthusiasts: https://github.com/adamfranco/curvature/wiki

The major limitation I've found is a dearth of road surface data that indicates whether roads are asphalt, concrete, gravel, or at a minimum paved/unpaved. Are there any non-proprietary data sets that contain this information for either the whole US or particular states? The TIGER dataset doesn't seem to contain road-surface information as far as I can tell.


TIGER 2010 has the MTFCC

Which is Classes with a code - S1100 for Primary Road (Highway)

You can investigate the codes S1500 - Vehicular Trail (4WD)

S1820 Bike Path or Trail

S1830 Bridle Path

*this might not be a perfect classification but a starting point

Full comprehensive list in Open Street Map


  • Thanks, @Mapperz, unfortunately the gravel roads in Vermont are mostly unclassified/residential roads that are well maintained rather than 4WD-only. It seems that they mostly fall under the S1400 category with many paved roads. – Adam Franco Dec 21 '12 at 1:11

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