text: how do trucking companies make there rigs go so slow like 65 mph and thats it?   many of the larger trucking companies will put a governor on the truck to make sure that the truck driver doesn't push the truck too fast. jb hunt is one of those companies. they probably do it to ensure the safety of the truck and the driver and those around them.  however, the other day i was coming back from a road trip when i got behind a truck from marten. they were hauling behind. i was in my car going about 80 behind them.