Speed Limits: National Maximum Speed Law (1974) —
High oil prices and supply disruptions during the 1973 oil crisis pushed Congress to pass the National Maximum Speed Law (NMSL), which prohibited speed limits higher than 55 miles per hour throughout the United States. Congress repealed the NMSL in the 1995 National Highway Designation Act, returning speed limit setting authority to the states. Since then, 34 states have raised speed limits to 70 mph or higher on some portion of their roadway systems.