Very few of those are real long-haul truck trips by North American standards. The U.S. and Europe have a comparable population, but the U.S. is about 2.5 times larger than Europe. Texas alone is larger than France.
A lot of the really long haul in the US is TOFL or COFL now. (Around here, at least, containers on flat cars seem more popular, as they can be double stacked while the trailers go single high. In the east, I understand that there are a lot of tunnels that can’t take the double stacks.)