One of the main reasons that a semitruck accident is so devastating for another driver is simply that the truck weighs so much more than that car. Many cars and small SUVs only weigh a few thousand pounds. When they get hit by the semi, it has so much more mass to contribute to the crash that it just tears through the smaller vehicle.
Crash test ratings and safety features can help, but they only do so much. In reality, in an accident like this, the smaller vehicle will always be at a massive disadvantage.
So, just how big is the difference? If your car weighs 3,000 or 4,000 pounds, how much can the 18-wheeler weigh?
Now, trucks are not always at their maximum weight limit. It depends on what they're carrying and if they're even loaded at all. However, that maximum is 80,000 pounds. If your car does weigh 4,000 pounds, that means that the semi weighs 20 times as much. It's no surprise that you are at such a disadvantage when it's the same weight as getting hit by 20 vehicles at the same time.
However, even 80,000 pounds seems small compared to some of the more rural areas of the world. In Australia, when semis have to take goods all the way across the thinly populated continent, they can weigh over 300,000 pounds and have four separate trailers. You can at least feel relieved that you'll never find anything like that in Louisiana.
Even so, accidents with 18-wheelers are very dangerous. If you get injured, make sure you know how to seek out financial compensation.