We've all heard about the car accident horror stories where a driver falls asleep at the wheel, thus causing an unfortunate wreck. These wrecks can be terrible ordeals that deal people serious injuries. However, add in a large truck, like a semi, and you have a recipe for disaster.
Trucks carry such momentum and power that when they strike another vehicle, it is usually more surprising when no one is seriously injured rather than multiple people dealing with extensive harm. That's why the trucking industry is so regulated; why truck drivers go through such extensive training and evaluation; and why rest rules exist. Truck drivers need to get enough sleep to be able to perform their job safely and effectively.
Clearly that was not a top priority for a 46-year-old truck driver and his company. Recently, the 46-year-old was working a shift that saw him work 36 hours straight. At the end of the shift (which ran from a Sunday morning to Monday night), he crashed into a state trooper and another truck. The accident killed the other truck driver (a 39-year-old) and left the state trooper with a bevy of serious (and likely life-changing) injuries.
Apparently the truck and the state trooper vehicle both had their emergency flashers on, but the 46-year-old truck driver did not see them. It is possible that he was asleep at the wheel, or that he was so fatigued that he simply wasn't paying attention to the road at the time of the crash.
Source: Chicago Tribune, "Prosecutors: Semi driver in fatal crash worked 36 hours with 3 1/2 hours sleep," Clifford Ward, Jan. 29, 2014