Commercial vehicles are usually larger than a car and carry commercial goods (semi or tractor trucks) or outfitted with heavy equipment for specific industry work (i.e., carpet cleaning) and utility trucks. Of course, any vehicle used for business activities is a commercial vehicle.
The law states the negligent party should compensate you when you are injured in a traffic accident. Truckers and trucking companies are federally mandated to carry higher limits of insurance on their vehicles due to the large number of traffic accidents causing injuries that are more serious and greater damage upon impact.
Many trucking companies have in-house experienced insurance adjusters who will try to settle the claim as quickly as possible - do not talk to them. You want to be sure to not give a statement, orally or written, to anyone other than your own insurance company and your attorney. This will allow you time to get well while someone is dealing with insurance adjusters on your behalf.
Even with what appears to be a "simple accident" where a commercial vehicle hits your car at a slower rate, does some minor damage to your car, causes minimal injury to you and their insurance company pays all of your medical and other expenses, you should still consult with an experienced attorney to be sure your legal rights are protected.
It is important to determine every person and company that could be liable in case the first person does not carry enough insurance to cover your claim. This can include the owner of the truck, the driver, the owner of the freight, the employer of the driver, the parent company, the manufacturer (if faulty equipment) and even the owner and driver if another vehicle was involved and several others.
As you can see, this type of accident can be very complex and requires an experienced attorney to help you navigate your claims to ensure you are protected.