I have had it when i have been in a car or a hgv joining a main road and i have had to slow down and adjust my speed as the car or hgv on the main carrageway haven’t moved out ,there is multiple reasons 1 they can’t due to traffic ,they can’t as if they do they will not be able to take their exit and they can’t be bothered …At the end of the day they have right of way wether we like it or not ,manners should dictate ,but nowdays manners in everyday life are in short supply…How many accidents are they nowdaus as people drive in the outside lane till their turn off then cut across 2 lanes to get their exit …I try to be couteous but if i have right of way on a main carrageway and i can’t move over i do not slow down to 10 mph to let someone in ,dithering causes accident .i do not want rammed from the vehicle behind because i braked hard to let someone out …It is up to those joining to adjust their speed