The United States Congress passed the "Uniform Time Act of 1966" (April 13,1966;;) to specify where and when daylight saving time was applied in the U.S., and authority was shifted to the United States Department of Transportation (USDOT).
The United States Congress passed the Uniform Time Act of 1966 to specify where and when daylight saving time was applied in the U.S. Previous to this law, each state was permitted to decide where and when daylight saving time took place. However, with the new federal law, authority over time zones was shifted to the United States Department of Transportation (USDOT).