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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

History of Daylight Savings Time

Friday, March 12, 2021

On the first Sunday in November millions of Americans turn their clocks back 1 hour to mark the end of Daylight Savings Time (DST), an annual practice that has its roots in transportation. Despite DST’s more than 50 years of nearly uniform observance since 1966, 29 states introduced legislation between 2015 and 2019 to abolish the twice-yearly switching of clocks.1 In May 2019, for example, Tennessee and Washington’s governors signed bills to extend DST year round.1 Several states in New England made similar proposals with one additional condition: they will only change to year-round DST if their neighboring states do the same, thereby avoiding the economic and transportation repercussions of neighboring states having different local times.1 The authority to change DST, however, ultimately lies with the Department of Transportation, a power it has held since its foundation in 1966.1,8

Time zones were introduced by the major railroad companies in 1883 to resolve confusion and avoid train crashes caused by different local times.3 As the United States entered World War I in 1918, the government delegated time zone supervision to the federal organization in charge of railroad regulation—the Interstate Commerce Commission (ICC).1,5 The new concept of DST was also overseen by the ICC to assist in the war effort.5 Initially introduced by Germany during the war to conserve fuel and power by extending daylight hours, the United States soon followed suit.1

After World War I, DST was nationally abolished but allowed to continue on a state-by-state basis.1 As a result, confusion and collisions caused by different local times once again became a transportation issue.1 In 1966, the Department of Transportation was founded to serve as a “focal point of responsibility for transportation safety” and given regulatory power over time zones and DST.1,4 DST was implemented uniformly across the Nation, with dates for the twice-yearly transitions set by law.1 This still holds true today. With the exception of Arizona and Hawaii, every state must continue to observe DST between March and November, unless otherwise exempted by State law.1


1. Clark, Corrie E., and Lynn J. Cunningham. 2018. Daylight Saving Time. CRS Reports (Library of Congress. Congressional Research Service). Available at as of October 2019.

2. Gordon, John Steele. Standard Time: We All Live By What Happened on November 18, 1883. American Heritage, Jul./Aug. 2001, pp. 22-23.

3. Phillips, Charles. A Day To Remember: November 18, 1883. American History, Dec. 2004, pp. 16-18.

4. United States. 1966. Creating a Department of Transportation: Hearings before a Subcommittee of the Committee on Government Operations, House of Representatives, 89th Congress, 2nd session, on H.R. 13200 a bill to establish a Department of Transportation and for other purposes. Washington, DC: U.S. GPO.

5. United States. 1966. Department of transportation act: report to accompany H.R. 15963. Washington, DC: U.S. GPO.

6. United States. 1966. Establish a Department of Transportation: Hearings, 89th Congress, 2nd session, on S. 3010, a bill to establish a Department of Transportation, and for other purposes. Washington, DC: U.S. GPO.

7. U.S. Department of Transportation. Daylight Savings Time (3/10/2014). Available at as of October 2019.

8. U.S. Department of Transportation. Uniform Time (2/13/2015). Available at as of October 2019.