Since August 2012 the US requires all states to annually report highways eligible for federal aid. The US Department of Transportation has begun to collect this data in a national highway dataset - called HPMS (the attributes) and ARNOLD (the spatial road network). This data is improving by the year and you can download it here.

We've downloaded it and reviewed it. While the alignment overall seems on par with OpenStreetMap, what's most interesting for OpenStreetMap is road attribute data like:

  • THROUGH_LA for lane count
  • HOV_LANES_ for carpool lanes
  • TOLL_CHARG for tolls

Eric Fischer rendered out a first map, take a look here:

DOT ARNOLD (yellow) in compared to OpenStreetMap (blue). Numbers are vehicles per day. Map courtesy Eric Fischer.

There's an opportunity to improve OpenStreetMap with ARNOLD data, but also for DOT and ARNOLD to listen to OpenStreetMap changes and detect quality issues in ARNOLD. Check out the data to get started. If you'd like to learn more about ARNOLD, get in touch with:

Thomas Roff
Office of Highway Policy Information

Update: clarify relationship between HPMS and ARNOLD.

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