This is clearly traceable to TIGER, the US Census data that most map providers use as the bedrock of their map data in the rural US, yet was never meant for automotive navigation.
TIGER classes pretty much any rural "road" uniformly - class A41, if you're interested. That might be a paved two-lane road, it might be a forest track. Just as often, it's a drainage ditch or a non-existent path or other such nonsense. It's wholly unreliable.
You can see this in OpenStreetMap easily. Navigate to the backwoods and look at the road types. It's predominantly highway=residential, the road type that A41 was mapped to in the TIGER import. highway=residential is usually meant for city streets and suburban residential roads. Not this.
So: help! I've genuinely spent weeks on this but it's a massive job. Paved road? Reclassify it as highway=tertiary (wider with centreline) or highway=unclassified (narrower, no centreline). Gravel or dirt graded road? highway=unclassified, surface=gravel (or =dirt). Rough, not recommended for most cars? highway=track. Genuinely a paved residential road? Keep the highway tag as it is, but delete the tiger:reviewed=no tag. Nothing there at all? Just delete it.
(My particular interest in this is bicycle routing. Bike routing usually prefers the smallest paved roads in the grid. It breaks if those "paved roads" are impassable desert tracks in reality. I take a very conservative view for my site, http://cycle.travel/map, precisely because I'm anxious about situations such as that described in the Ars article.)
Oh wow. That seems like a horrible state of affairs. I've worked in bicycle routing before (Germany) and we had a very good, curated mesh of bicycle paths, tagged for suitability for certain bike types. We also used OSM and previously Navteq for roads to also use for routing and at least in Europe the tagging seems to be mostly useful.
But I can see now why navigation breaks so horribly when all you have is an essentially uncategorised road network.
Another issue: In my experience, in north america, navigation is more focused on compass points (take Road XYZ north, southwest, etc) whereas in Europe it is more focused on semantic directions (turn right on highway towards Groningen). The european way allows for easier verification if the road is actually the road you want to take (as in: do I really want to drive to Hobbington? The street sign says I should take the second exit, so I go with that.
As a cyclist I've been looking for a way to get cycle routes that avoid unpaved surfaces (in the UK). Does/can your site do that? Is there an android app that can do that?
cycle.travel prefers paved surfaces but will route via (good) unpaved surfaces if it'd save a long detour or avoid a busy road. It highlights unpaved sections in green so you can easily drag the route away. Alternatively, bikeroutetoaster.com has a paved-only routing option, and maybe gpxeditor.co.uk too, though the sites can be a bit flaky.
> So: help! I've genuinely spent weeks on this but it's a massive job.
I'd love to help, but how? Is the only option for people to go driving all these "roads" in person to see which ones are actually roads, or is there another source of data that can be used to compare against?
TIGER classes pretty much any rural "road" uniformly - class A41, if you're interested. That might be a paved two-lane road, it might be a forest track. Just as often, it's a drainage ditch or a non-existent path or other such nonsense. It's wholly unreliable.
You can see this in OpenStreetMap easily. Navigate to the backwoods and look at the road types. It's predominantly highway=residential, the road type that A41 was mapped to in the TIGER import. highway=residential is usually meant for city streets and suburban residential roads. Not this.
So: help! I've genuinely spent weeks on this but it's a massive job. Paved road? Reclassify it as highway=tertiary (wider with centreline) or highway=unclassified (narrower, no centreline). Gravel or dirt graded road? highway=unclassified, surface=gravel (or =dirt). Rough, not recommended for most cars? highway=track. Genuinely a paved residential road? Keep the highway tag as it is, but delete the tiger:reviewed=no tag. Nothing there at all? Just delete it.
(My particular interest in this is bicycle routing. Bike routing usually prefers the smallest paved roads in the grid. It breaks if those "paved roads" are impassable desert tracks in reality. I take a very conservative view for my site, http://cycle.travel/map, precisely because I'm anxious about situations such as that described in the Ars article.)