2000—Pub. L. 106–564, in first sentence, substituted “nine zones” for “eight zones” and, in second sentence, substituted “; that of the eighth” for “; and that of the eighth” and inserted before period at end “; and that of the ninth zone on the one hundred and fiftieth meridian of longitude east from Greenwich.”

1983—Pub. L. 97–449 substituted “Secretary of Transportation” for “Interstate Commerce Commission”.

1966—Pub. L. 89–387 increased the number of time zones from five for the territory of continental United States to eight for the territory of the United States, inserted the “exception phrase”, substituted “solar” for “astronomical” time, established the first zone on basis of the 60th degree of longitude west from Greenwich, redesignated as the second through the fifth zones based on the 75th, 90th, 105th, and 120th degrees former zones one through four based on such degrees, established the sixth zone based on the 135th degree, redesignated as the seventh zone based on the 150th degree former fifth zone based on such degree, and established the eighth zone based on the 165th degree, substituted “interstate or foreign commerce” for “commerce between the several States and and with foreign nations” and defined “interstate or foreign commerce”.

Act Mar. 19, 1918, ch. 24, 40 Stat. 450, as amended, which is classified to sections 261 to 264 of this title, is popularly known as the “Calder Act”.

Section 5 of act Mar. 19, 1918, repealed all conflicting acts and parts of acts.

Act Mar. 31, 1949, ch. 43, 63 Stat. 29, authorized the Board of Commissioners [now the Council of the District of Columbia] to establish daylight-saving time in the District of Columbia.

Act Sept. 25, 1945, ch. 388, 59 Stat. 537, provided, that, notwithstanding the provisions of act Jan. 20, 1942, ch. 7, 56 Stat. 9, which provided for war time, the standard time for each zone as provided for in sections 261 to 264 of this title should again become effective as of Sept. 30, 1945, at 2:00 A.M.