"Additionally, heavy machinery refers to any type of vehicle that weighs more than 5,000 pounds and requires more than one person to operate. Cars, tractors, trucks, buses, forklifts, and other industrial vehicles that require special training or licensing to operate are included." (source)
why do you think so many medications n shit are like "do not operate heavy machinery after using" or whatever!!! I hadn't considered that cars would fall under heavy machinery until someone pointed it out to me, but it does make sense