Every commercial truck in California must follow federal and state guidelines that govern virtually every aspect of the business, from qualifications for drivers to how often the trucks must be checked for maintenance. How many hours at a time the driver may be on the road and the legal relationship between the driver and trucking company are all determined by these regulations, which are intended to make the road safer for all motorists. When these rules are breached, there may be a legal presumption that the driver or trucking company is legally responsible for the accident.