A large or "big truck" is generally classified as one weighing more than 10,000 pounds and they can weigh as much as 80,000 pounds. By contrast, a passenger car weighs a little more than half that amount. That means that cars involved in big truck crashes are generally the big losers. The most common cause of big truck crashes is driver fatigue. The law requires a driver to have at least 10 hours of rest for every 14 hours they drive. Most trucks are also equipped with black boxes that record the speed, location, and driving times of the vehicle. If the driver is negligent, the black box may reveal those facts. In addition, if the driver works for a trucking company or is under contract to a company that has demanding delivery times, they may be liable for pushing that driver beyond normal bounds. Learning those facts may be difficult without the help of an experienced truck accident attorney.