Poor drivers probably has been in the seat the last 24h, living on coffee and burgers from the gas station.
Plow trucks are used on large high ways, but most is cleared with tractors, it's a multitool, lot of farmers do plowing in the winter, and it's a lot easier to get drivers for tractors, taking driver license for large trucks are very, very expensive so few bother to do that just to has it as a sidejob.