Big rigs, tractor-trailers, and semi-trailers - whatever you prefer to call them - cause a whopping 500,000 accidents per year. About 130,000 people are injured in these accidents. One percent of these accidents (about 5,000 of them) kill one or more people. This isn't surprising since these behemoth vehicles can weigh 30,000 lbs when empty and a crushing 80,000 pounds…