The answer is somewhat complicated.
To start with, accidents involving semi-trucks are generally more complicated than your average car accident. The smaller vehicle often suffers more damage than it otherwise would, and injuries are often more serious. Mortality is often more likely, as well.
This is simply about the size. Semi-truck engines are six times heavier than car engines, and with a loaded trailer (without any oversize licensing or multiple trailers involved) can weigh up to 80,000 pounds. That is 40 tons. You can look up the weight of your vehicle via the internet right now, but most vehicles weigh somewhere in the range of 5000 pounds.
Accidents that would be relatively minor if involving another vehicle can be very severe when semi-trucks are involved, just because of this size difference. Truck drivers have to train and get special licensing because of the elevated dangers involved in the size of semi-trucks. As a result, there are many more rules and regulations one must follow as a truck driver.
You may have driven past weigh-in stations on the highway, sometimes. These are not there to make sure that the truck isn't losing goods as it goes along, but to ensure that the load in the trailer is properly balanced. Many thousands of pounds sliding around in the back of the trailer can be a road hazard. If you've ever seen trucks parked in odd places- sometimes they're parked on the shoulder of highway off or on-ramps. This is because they are only allowed to drive for so long without resting. These are just two small examples of the expanded driving rules and regulations that truckers have to follow.
In addition to that, who owns and is responsible for the truck and the load that's being carried can be tricky to find out. Some truck drivers own their rig, and some use rigs that the company owns. Truck drivers who own their rig sometimes lease their trucks from the company that they ship goods for, shipping goods solely or mostly for that company. Other truck drivers own their vehicles outright and are essentially allowed to work as their own company, carrying loads under their own authority.
The insurance policies for truckers is, to put it mildly, complicated. Difficult for the truckers to navigate on their own when they're shopping for a policy, much less for dealing with after an accident has taken place.
This is why there are lawyers specifically for accidents involving semi-trucks. They have the experience with the more complicated legal situation, as well as understand the kinds of rules and regulations truckers, and the companies that employ them must follow. If you have any more questions about why a truck accident attorney may be right for you, consider contacting your local experts.