You can make a self driving truck/electric vehicle lane where the speed limit is 80km/h. Paint a green line in the middle of the ev-lane and it should make self driving more easy to implement. Reason for slower speed wind resistance is far less at 80km/h. Energy use is quadratic concerning speed. So make a movie streaming ev-lane.
Also one could fit cars with rail gear and run them on rail tracks on the highway which would lessen the tire friction roll resistance losses. Technology for allowing cars to run on rail tracks already exists for railway maintenance cars. Self driving on rail track is also much easier to implement.
Also one could fit cars with rail gear and run them on rail tracks on the highway which would lessen the tire friction roll resistance losses. Technology for allowing cars to run on rail tracks already exists for railway maintenance cars. Self driving on rail track is also much easier to implement.
https://en.m.wikipedia.org/wiki/Road–rail_vehicle
Safety from car crashes would also be far safer at 80km/h than higher speeds.