The cause of the accident will determine whether you deal with the individual driver, insurance company or trucking company. If the individual driver violated safety regulations resulting in the collision, then he or she may be at fault. However, semi-truck accidents are not always directly caused by poor driving. Trucking companies can be found responsible for things like dangerous cargo, inadequate training, failure to enforce safe driving practices or other safety violations. Product manufacturers may also be liable for defective vehicles or parts.