Snow plows are emergency vehicles, but typically do not exceed the posted speed limit. Snow plows are big, noisy pieces of equipment. It may appear at times that the snow plow operator is driving too fast for road conditions.
Many times the engine sound and noise of the plow scraping the pavement give the perception that the truck is flying down the street, when in actuality, they are only moving at 10 to 15 miles per hour. The plows do move faster on open stretches of road to push the snow farther off of the road to ensure there is sufficient space to stack the snow from the next storm.