From poking around in the source code I found this 282M SQLite database:
wget https://services.arcgis.com/xOi1kZaI0eWDREZv/arcgis/rest/services/NTAD_North_American_Roads/FeatureServer/replicafilescache/NTAD_North_American_Roads_3862439624850511818.geodatabase
I can't figure out how to read it though. I get this error: Connection to NTAD_North_American_Roads_3862439624850511818.geodatabase failed check: no such module: VSRS
As far as I can tell VSRS is a proprietary Esri thing. "This NTAD dataset is a work of the United States government as defined in 17 U.S.C. § 101 and as such are not protected by any U.S. copyrights. This work is available for unrestricted public use."
I based my work on this, maybe the link is out, thx for testing. The dataset has already been consumed and collapsed into a smaller graph representation.
if you follow the link in the github readme, there are a few other download options for the dataset, like CSV or shapefile