California has a number of state highways that are restricted by length, either total length or 'kingpin' length. It's curvature that's the issue, though curves usually go along with grades. In fact the worst grades are on the inside of sharp curves. I'm thinking in particular of Sonora Pass (108). I know of some city street intersections like that in the Seattle area.
Many of those California roads were originally wagon tracks, and due to terrain and usage have not seen much change in route or grade. CA162 (Lone Pine) follows a dry (usually) steam bed, crisscrossing it without bridges or culverts, and minimum of cut and fill.
RV posters often worry about switch backs. But as one who grew up in the mountains, a true switchback is one where a pickup has to execute a 3 point (or more) turn, the equivalent of turning around in the middle of a city street. The only paved route that I've encountered like that is in Yoho Nat Park (BC). One pair of curves is signed, telling vehicles longer than 7 meters (21 ft) to back up the middle leg.