Except for New Hampshire, all states and the District of Columbia require adult front-seat occupants of motor vehicles to use seat belts. Adult rear-seat passengers are also covered by the laws in 31 states and the District of Columbia. Children are covered by separate laws.

State seat belt laws are divided into two categories: primary and secondary. Primary seat belt laws allow law enforcement officers to stop a motor vehicle and to issue a ticket or citation to a driver or passenger for not wearing a seat belt without any other traffic offense having occurred. Secondary seat belt laws only allow law enforcement officers to issue a ticket or citation for not wearing a seat belt when there has been another traffic offense by an occupant of the vehicle for which the occupant may be issued a ticket or citation.

In Delaware, seat belt use is mandatory for all occupants of a motor vehicle, and the state enforces primary seat belt laws. This means that law enforcement officers in Delaware have the authority to stop a vehicle and issue a citation to the driver or passengers solely for not wearing a seat belt, without needing to observe any other traffic violation. The law applies to adult front-seat occupants, and Delaware also requires adult rear-seat passengers to wear seat belts. Additionally, Delaware has specific laws in place to protect children while traveling in a motor vehicle, which include requirements for child safety seats and booster seats, depending on the child's age, weight, and height. Non-compliance with these seat belt and child restraint laws can result in fines and points on the driver's license.