It is the policy of the United States to promote the adoption and observance of uniform time within the standard time zones prescribed by sections 261 to 264 of this title, as modified by section 265 of this title. To this end the Secretary of Transportation is authorized and directed to foster and promote widespread and uniform adoption and observance of the same standard of time within and throughout each such standard time zone.
15 U.S. Code § 260. Congressional declaration of policy; adoption and observance of uniform standard of time; authority of Secretary of Transportation
1983—Pub. L. 97–449 substituted “Secretary of Transportation” for “Interstate Commerce Commission”.
“This Act [enacting this section and sections 260a, 266, and 267 of this title and amending sections 261 to 263 of this title] shall take effect on April 1, 1967; except that if any State, the District of Columbia, the Commonwealth of Puerto Rico, or any possession of the United States, or any political subdivision thereof, observes daylight saving time in the year 1966, such time shall advance the standard time otherwise applicable in such place by one hour and shall commence at 2 o’clock antemeridian on the last Sunday in April of the year 1966 and shall end at 2 o’clock antemeridian on the last Sunday in October of the year 1966.”