Map Monday: All US Trunk Highways ADT

Here’s an ambitious online mapping project that combines OpenStreetMap with something called the “latest Highway Performance Monitoring System (HPMS) national highway dataset provided by the Federal Highway Administration.” Basically, it’s all the US highways in the country, shaded by AADT (average daily traffic). Kind of cool to see, and you get a real sense of where all the cars are driving:


Here’s some more info from

Take a look at the map comparing HPMS (yellow) with OpenStreetMap (blue). You can see that the geographical alignment between the two datasets is on par. The coverage of OpenStreetMap is better, but full road coverage is not the goal of HPMS. We’ve visualized the traffic density attribute in HPMS as line thickness to highlight the regional and national significance of different roads. Thicker yellow lines are more traffic and thinner yellow lines are less traffic. Zoom in to see the numbers for average vehicles per day.

Check out the entire project here. is a non-profit and is volunteer run. We rely on your support to keep the servers running. If you value what you read, please consider becoming a member.

3 Responses to Map Monday: All US Trunk Highways ADT

  1. Alex Cecchini
    Alex Cecchini February 2, 2015 at 1:42 pm #

    Unless you believe that a significant portion of freight originates and terminates within each major/minor metro area (I don’t *), this is the best way to visually see that most travel within Minnesota is discretionary mode choice. In other words, there’s a lot of driving simply because people like to and because we’ve built transportation systems that encourage it.

    *I base this off 3 stats:
    1) FHWA data says for all “urban areas” freight (single unit and comb. trucks) VMT accounts for only 6.6% of VMT for all road functional classifications.
    2) MnDOT data shows “Heavy Commercial” + “5 axle” VMT on trunk highways is 13.8% of all trunk highway VMT across the state
    3) Freight travel data from FHWA shows that only 28% of freight VMT in MN is “within” (not to another state or originating somewhere else with a destination in MN). I would assume this ratio is similar within a metro area.

    • Adam Froehlig
      Adam Froehlig February 2, 2015 at 7:10 pm #

      Point of clarification: the HPMS database covers all streets and roads functionally classified as collector or above. It includes far more than just “US highways” (which itself isn’t really accurate as you also have state highways and the Interstates). In terms of Minnesota, this would include most of the CSAH and MSAS system as well.

      Regarding Alex’s comment….in the Twin Cities case a significant portion of freight *DOES* originate or terminate in the Metro, which has a huge number of freight, trucking, and shipping companies (a number I saw years ago was on the order of 150).

      • Alex Cecchini
        Alex Cecchini February 2, 2015 at 9:01 pm #

        My point wasn’t that we don’t have a lot of freight miles, more that VMT from household (and yes, other professional but light duty vehicle) vastly outweighs it. And while we may have a lot of freight enter/leave the metro, we shouldn’t expect intra-metro freight travel (ex Plymouth to Eagan) to be any more/less than other urban areas where the VMT share is below 10%.

        I believe MN as a state is 13th in total freight ton-miles, so certainly packing above our weight compared to GDP (17th) and population (21).

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