Years ago the Australian version of the Department of Motor Vehicles installed a series of signs that read “SLOW VEHICLES USE LEFT LANE”.
Unfortunately nobody wanted to be seen as the slow car so everyone stayed in the right lane, leaving the left lane for only the slowest vehicles. Then some bright spark changed the words.
The signs were replaced with the words “KEEP LEFT UNLESS OVERTAKING” and now everyone uses the left lane.
The right words make such a difference.