Determining who is responsible for a truck accident will vary from accident to accident. In some cases, the truck driver might be responsible for violating motor vehicle laws, such as speeding or driving under the influence. Trucking companies can be held accountable for negligence related to dangerous cargo, federal trucking violations, etc., as well as for the actions of their employees. Manufacturers could also be liable if there was a defective part on the truck that contributed to the accident.