Gunner Asch wrote:

"he multi-vehicle collision on Interstate 5 began when an 18-wheeler was
traveling through a tunnel. As the driver traveled at more than 65 mph,
the truck jackknifed, crashing into a wall. Vehicles behind the truck
were able to slow down and avoid hitting the 18-wheeler. Further down
the tunnel, however, other big rigs, pickup trucks, and cars were not as
lucky. Several vehicles crashed into one another and fuel from large
trucks set off a raging fire. Motorists were forced to abandon their
cars and run for safety. The tunnel instantly became an inferno, killing
3 people. One was a 6-year-old boy who managed to survive the crash, but
burned to death. In all, the accident included 33 trucks, 26 of which
were consumed by flames."


This is why licensing is more stringent for big rigs. In a normal car or
pickup there is a limit to the amount of collateral damage you can do,
in an 80,000# semi with 150+ gal of diesel and who knows what cargo on
board the potential casualties are substantially greater.