[mantas]

Once you get away from highly populated and developed areas, there're lots of single-lane roads. Let alone that single-lane roads are used as backups when inevitable accident happens on multilane. Of course, there's not as much traffic in such areas as in those with multi-lane highways.

[kuschku]

Well, the current tests with self-driving trucks are almost exclusively by european carmakers on German roads – where 2 to 3 lanes are common about everywhere, and trucks are limited to 80km/h or 100km/h anyway.