Either or both, depending on what the evidence shows. Truck drivers can be held liable if they acted negligently by, for example, driving while distracted. On the other hand, trucking companies must ensure their employees are adequately trained and drive safely, so the company can be held liable for an accident if they failed in these duties. Also, companies are typically held vicariously liable for their employee’s negligence. This means the trucking company would be responsible even if it didn’t do anything wrong.