Seat belt laws in the United States
Most seat belt laws in the United States are left to state law. The first seat belt law was a federal law, Title 49 of the United States Code, Chapter 301, Motor Safety Standard, which took effect on January 1, 1968, that required all vehicles (except buses) to be fitted with seat belts in all designated seating positions.
Source: Wikipedia — Seat belt laws in the United States (CC BY-SA 4.0)