The civil courts in the United States have a standard for proving whether or not a driver was negligent. You need to establish that the truck driver:
1. Owed a duty of care
2. Breached that duty of care, and was therefore negligent
3. That breach of duty caused your injuries
4. You suffered harms and losses as a result
Commercial truck negligence can be difficult to prove because multiple parties could all play a role in the accident. Even though the truck driver was the one behind the wheel, others could potentially be at fault for your injuries, including the trucking company they work for.