Why do the PASSENGERS would like to increase the SPEED LIMIT during stretch? I about to DM this and got my doubts on that. Don't know if the SPEED LIMIT on his own would rise a lot with my two players, maybe if the players have some sort of convince to have more SPEED LIMIT
Raising the speed limit makes less stretches between stops, so there is a rare instance that it MIGHT be useful to passengers. But most of the time they will probably opt to lower it.
Remember that the player can choose to raise the speed limit if they would take damage.
Youe main job as the GM is to constantly apply pressure to the passengers, via the environment, NPCs, and the driver!