Douglas Bader, an Illinois State Trooper, sat in his squad car with the lights flashing when his car was struck by a tractor-trailer, causing his vehicle to burst into flames. Balder had stopped to deal with a big-rig that had stalled in the right traffic lane. Both a bright yellow tollway assistance vehicle and a tow truck also were stopped, making the scene obvious to approaching vehicles. The patrol car flashers were activated, and flares were positioned behind the vehicles. The tollway truck also was positioned behind the vehicles while flashing a large blinking arrow and amber hazard lights. Despite this obvious traffic obstacle on the side of the road, the driver of a flatbed big rig slammed into the patrol car at 63 miles per hour. The investigation conducted by the National Transportation Safety Board (NTSB) subsequently revealed that the truck driver was falling asleep. The gas truck of the patrol car exploded, and Bader suffered severe burns over a third of his body.