Many, not all, truck refueling stations will have one of the lanes labeled for RV's. If this is the case use this lane. This lane will have a smaller diesel nozzle and a slower fill rate. Truck islands will have large size nozzles and pump up to 60 GPM. These stations do not want you filling up at 60GPM because no matter how fast you rig will take the fuel it is going to foam and you will have fuel coming out at your feet. If no lane labeled for RV's you still may have to fuel at less then the max rate to keep fuel foam from pilling out before the pump shuts off.