The driver of the semi-truck said he didn’t notice the car. How could you not notice a vehicle that is hooked to the side of the truck you are driving?

From the video description:

“In California's Cajon Pass, a sedan became wedged under a truck and was dragged for four miles. The car was stuck under a tractor-trailer, while the truck driver continued to drive up the pass. The sedan's driver can be seen waving his hands outside of the vehicle and shouting for help. Other drivers honked to get the trucker's attention, although the trucker didn't notice until another car got in front to stop the truck. Luckily, the sedan's driver was uninjured. According to the California Highway Patrol, this crash is not considered a criminal incident.”