Features – 24/7: A Resource Guide to the Law of Time Standards

Stephen Young is a reference librarian at The Catholic University of America, Kathryn J. DuFour Law Library. Stephen has written extensively in the area of United Kingdom law, and has previously contributed a number of articles to LLRX.com.

“Everyone appreciates the long, light evenings. Everyone laments their shortage as Autumn approaches; and everyone has given utterance to regret that the clear, bright light of an early morning during Spring and Summer months is so seldom seen or used.”

William Willet, “The Waste of Daylight,” 1907.

Twice a year the majority of United States residents participate in a ritual governed by federal law; they turn their clocks forward one hour in the spring, and they turn their clocks backward one hour in the fall. This biennial adherence to the Uniform Time Act of 1966 is undergone with little or no thought to the legislation behind this process. This act is but one example of the many ways in which the main element that governs our day is itself governed by a variety of statutes and regulations. This guide will seek to provide a general overview of the literature and primary materials relating to the law of time standards. It should be noted that the law regarding the computation of time (e.g., for the purposes of contracts, judicial proceedings, limitation of actions, etc.) is outside of the scope of this article.

Historical Background

During its history the United States has seen a transformation from a country where time was determined locally according to astronomical projections, to a country that now adopts nine separate time zones. The impetus for standardizing the telling of time is credited to the railroads, an industry which needed a standard system for coordinating its schedules. Following the example of railroads in Britain, the railroads in the US implemented a system of standard time divided into four distinct time zones (Eastern, Central, Mountain, and Pacific). Although the system, commonly known as “railroad time,” was initially adopted in many parts of the country in 1883 it was many years before it was accepted nationwide. Congress did not pass legislation standardizing the time zones until the passage of the Calder Act on March 19, 1918. International or Universal standard time, a method of telling time worldwide, was originally devised by Sir Sanford Fleming in 1878 and approved at the International Prime Meridian Conference in Washington, DC in 1884 (implemented January 1, 1885). This conference was also responsible for choosing Greenwich Meridian as the Prime Meridian of the world.

Time in the United States Today

Time in the United States is currently split into 9 time zones; Atlantic Standard Time, Eastern Standard Time, Central Standard Time, Mountain Standard Time, Pacific Standard Time, Alaska Standard Time, Hawaii-Aleutian Standard Time, Samoa Standard Time, and Chamorro Standard Time. Each of the time zones is based on the existence of United States territory relative to its degree of longitude west of Greenwich. For every 15 degrees of longitude west of Greenwich the clock is turned back one hour (e.g., Eastern Standard Time is based on the mean solar time of the seventy-fifth degree of longitude west from Greenwich, and therefore the time in that time zone is five hours behind GMT). The most recent change to the list of U.S. time zones was on December 23, 2000 with the addition of the ninth time zone, Chamorro Standard Time (ChST), which covers Guam and the Commonwealth of the Northern Mariana Islands (PL 106-564). Chamorro Standard Time is 14 hours ahead of Eastern Standard Time, and is the only US time zone located west of the International Date Line. It is named after the indigenous people of the region.

Daylight Saving Time

William Willet, the author of the quote at the beginning of this article, is often credited with spearheading the modern movement to introduce Daylight Saving Time (DST) or “Advance Time” in Great Britain. Willet’s efforts resulted in the introduction of “British Summer Time” (BST) through the passage of the Summer Time Act (6 & 7 Geo. 5 c.14) in 1916. However, credit must also be given to Benjamin Franklin who proposed this idea in 1784 in his essay “An Economical Project.” The first introduction in the US of DST was two seventh month periods in 1918 and 1919 for the purposes of conserving resources during World War I (see the original Calder Act at 40 Stat. 450 which also established the time zones).

Following World War I DST was abolished on a national level and thus became a matter of local option. The beginning of the Second World War saw the need to reintroduce DST on a national basis. On February 9, 1942 the Roosevelt administration instituted year-round DST (56 Stat. 9), known at the time as “War Time,” until the end of the war in September 1945 (59 Stat. 537). Once again the end of a war led to an end to the nationwide adoption of DST, however states and local authorities were free to choose whether or not to adopt DST. The resulting chaotic picture led to the Interstate Commerce Commission, and later the Department of Transportation (the transfer of power from the ICC to the DOT was formalized by the Uniform Time Act of 1966), to push for a nationwide standard on DST. While opposition to a nationwide standard was voiced by the agricultural industry, far louder cries in favor of standardization were made by a variety of industries including the transportation and broadcasting industries.

The resulting push for standardization culminated in the adoption of the Uniform Time Act of 1966. The act provided for a standard time within each of the established time zones. In addition it provided for DST: clocks were to be advanced one hour at 2:00 a.m. on the last Sunday in April and turned back one hour at 2:00 a.m. on the last Sunday in October. Individual states could exempt themselves from DST providing they did so entirely. The first state to take advantage of the opt-out clause was Arizona in 1968. An amendment to the act in 1972 (PL 93-182, 86 Stat. 116) addressed the confusion caused by states that straddled two or more time zones. Further amendments to the act were made in 1973 as a result of the OPEC oil embargo (PL 93-182, 87 Stat. 707), and 1974 as a result of concerns over the safety of children going to school in the dark (PL 93-434, 88 Stat. 1209). The first of these amendments, The Emergency Daylight Saving Time Energy Conservation Act 1973, saw the introduction of a trial period of year-round DST starting on January 6, 1974. The latter amendment, The Emergency Daylight Saving Time Energy Conservation Act 1974, restored standard time effective November 1974.

With the ending of the trial period of year-round DST in 1975, the Department of Transportation, the government agency charged with the responsibility for enforcing the law, initiated an investigation into the effects of DST. Their report, The Daylight Saving Time Study: A Report to Congress, concluded that there might be some modest benefits to be gained from extending DST to a longer period than the traditional six-month period. The National Bureau of Standards review of the DOT report was inconclusive although it did acknowledge some of the benefits highlighted in the DOT’s study (see Review and Technical Evaluation of the DOT Daylight Saving Time Study).

The most recent amendment to the laws regarding DST occurred in 1986 with the passage of the Fire Prevention and Control Authorizations Act 1986 (PL 99-359, 100 Stat. 764). This amendment, citing the benefits to energy conservation and leisure time outlined in the DOT and NBS reports, established the changeover dates for DST observed today. DST begins on the first Sunday in April and ends on the last Sunday in October. Currently Arizona (except for the Navajo Indian Reservation), Hawai’i, the part of Indiana in the Eastern Time zone (comprising 77 counties), American Samoa, Puerto Rico, the US Virgin Islands, Guam and the Northern Mariana Islands do not observe DST. It should be noted that Indiana observes three time standards; the majority of the state observes Eastern Standard Time all year (no observance of DST), 10 counties in the northwest of the state observe Central Standard Time (and DST), and 5 counties in the southeast of the state observe Eastern Standard Time (and DST). A state can apply for a change in its time zone or its observance of DST by submitting a request from the governor, state legislature, or other official body to the Department of Transportation. This request should detail the economic and social benefits of such a move (an example of this process can be viewed here).

Federal Legislation

The following federal statutes have governed the law of time standards in the United States. It is important to realize that statutes providing for a standard of time have also been enacted in most of the states.

  • The Federal Standard Time Act (“Calder Act”), March 19, 1918 (40 Stat. 450).
  • Amendment to the Federal Standard Time Act, March 4, 1921 (41 Stat. 1446).
  • War Time Act, January 20, 1942 (56 Stat. 9).
  • Amendment to the War Time Act, September 25, 1945 (59 Stat. 537).
  • District of Columbia Daylight Saving Time Act, March 31, 1949 (63 Stat. 29).
  • The Uniform Time Act of 1966, April 13, 1966 (80 Stat. 107).
  • The Uniform Time Act Amendment, March 30, 1972 (86 Stat. 116).
  • Emergency Daylight Saving Time Energy Conservation Act 1973, December 15, 1973 (87 Stat. 707).
  • Emergency Daylight Saving Time Energy Conservation Act 1974, October 5, 1974 (88 Stat. 1209).
  • Fire Prevention and Control Authorizations Act 1986, October 8, 1986 (100 Stat. 764).
  • Establishment of a Standard Time Zone for Guam and the Commonwealth of the Northern Mariana Islands Act 2000, December 23, 2000 (114 Stat. 2811).

Executive Authorization

Although far from exhaustive, the following regulations and Executive Order serve to highlight the extent to which the administration of time standards in the United States falls under the jurisdiction of the Department of Transportation.

  • Department of Transportation, Standard Time Zone Boundaries (49 CFR 71).
  • Executive Order 11751 December 15, 1973, Authorizing the Secretary of Transportation to Grant Exemptions From Daylight Saving Time and Realignments of Time Zone Limits (38 Fed. Reg. 34725).

Judicial Interpretation and Application

The courts have provided their own interpretation and application of federal, state and local legislation concerning time standards. Even before the federal government formalized a time standard in 1918 the state and federal courts were asked to rule on cases involving disputes over this matter. The following select cases highlight some of the important issues raised in this area of law. For the purposes of convenience they have been divided into three general, and arguably overlapping, categories. The placement of a case in one category does not necessarily preclude its relevance to one or more other categories.

1. Daylight Saving Time & Time Zones

In Michigan Farm Bureau v. Hare (1967) 379 Mich. 387, 151 NW2d 797, the court dismissed a lower court’s ruling in holding that the “state” as a whole, not just the state’s legislative body, could take action to exempt the state from the Uniform Time Act of 1966. Thus the federal statute did not preclude the circulation of a referendum petition on a state act exempting the state from the Uniform Time Act of 1966. Additional DST cases include, Nevada Mining Assn v. Erdoes (2001) 26 P.3d 753, State v. Badolati (1942) 241 Wis. 496, 6 N.W.2d 220, Webb v. Clatsop County School Dist. (1950) 188 Or. 324, 215 P.2d 368, Carroll v. Bayonne (1924) 99 N.J.L. 493, 124 A. 613, Kanagur v. Hare (1968) 284 F. Supp 426, Playboy Club Inc. v. Myers (1968) 431 S.W.2d 228, and MacDonald v. Sheriff (1953) 148 Me. 365, 94 A.2d 555. Case law involving disputes over time zones include Salt Lake City v. Robinson (1911) 39 Utah 260, 116 P. 442, Globe & R.F. Ins. Co. v. David Moffat Co. (1907) 154 F. 13.

2. States’ Rights

The United States Supreme Court weighed in on the issue of time standards in Massachusetts State Grange v. Benton (1926) 272 US 525. In this decision the court affirmed a District Court decision declaring that federal statutes in this area are not exclusive of state action. A Massachusetts act was therefore not unconstitutional or inconsistent even though it sought to advance standard time by one hour. Other cases highlighting states’ rights in this area include State Election Bd. v. McClure (1963) 243 Ind. 658, 189 N.E.2d 711, and State ex rel. Schirado v. Frye (1968), 157 N.W.2d 830.

3. Administrative Enforcement

The courts in Time Life Broadcast Co. v. Boyd (1968) 289 F. Supp 219, held that the Department of Transportation was required to enforce the Uniform Time Act of 1966, and could not encourage citizens of the state of Indiana to disobey the act. Additional cases determining the administrative responsibility of the Department in this area include Allied Theatre Owners, Inc. v. Volpe (1970) 426 F2d 1002, and Whitmer v. House (1967) 198 Kan 629, 426 P2d 100.

Secondary Resources

The following list of secondary sources includes monographs, articles, and government reports on the law of time standards. Congressional hearings have not been included, however Congressional Committee Reports (and one committee print) are listed. It is also worth noting that the two major legal encyclopedic works have relevant entries on the topic (see specifically 74 Am Jur 2d, Time §2-3, and 86 C.J.S., Time §3).

  • Interstate Commerce Commission, Standard Time Zone Investigation No. 10122, (1918).

  • Annotation, Legal Aspects of Daylight Saving, 71 L.Ed. 388 (1926).

  • Seattle Public Library, Daylight Saving: Selected List of References on Daylight Saving (1933).

  • Annotation, Standard or System of Time, 143 ALR 1238 (1943).

  • Edmund Arpin, Daylight Saving Time in the U.S. Wisconsin Legislative Library (1953).

  • U.S. Congress. Uniform Time Legislation. Report of the Senate Committee on Commerce No. 89-268 (1965).

  • U.S. Congress. Uniform Time Act of 1966. Report of the House Committee on Interstate and Foreign Commerce No. 89-1315 (1966).

  • Robert A. Shapiro, Annotation, Construction and Application of Federal Uniform Time Act of 1966, 34 ALR 3d 1148 (1970).

  • U.S. Congress. Uniform Time Act Amendment. Report of the House Committee on Interstate and Foreign Commerce No. 92-915 (1972).

  • Maureen Ayton, Daylight Saving Time: Background and Legislative Analysis. CRS Report to Congress (1974).

  • U.S. Department of Transportation. The Daylight Saving Time Study: A Report to Congress. (1975).

  • U.S. Congress. Daylight Saving Time Act of 1976. Report of the House Committee on Interstate and Foreign Commerce No. 94-1443 (1976).

  • U.S. National Bureau of Standards. Review and Technical Evaluation of the DOT Daylight Saving Time Study (1976).

  • U.S. Congress. House Committee on Interstate and Foreign Commerce, The Uniform Time Act of 1966 and other Related Acts and Background Information for Committee Consideration of HR 13089 and similar bills relating to Daylight Saving Time. Committee Print No. 94-22 (1976)

  • U.S. Congress. Daylight Saving Extension Act of 1985. Report of the House Committee on Energy and Commerce No. 99-185 (1985).

  • Heidi G. Yacker, Daylight Saving Time. CRS Report to Congress (1998).

  • Clark Blaise. Time Lord: Sir Sandford Fleming and the Creation of Standard Time (2002).

A Note on International Scales and Foreign Standards

Although the focus of this article is on the law as it pertains to United States time standards, it is nevertheless important to point out that time standards are also impacted by international scales and laws in other non-US jurisdictions. Since 1972 the internationally accepted scale for determining time has been Coordinated Universal Time (UTC). Based on the accuracy of atomic time (TAI), UTC accounts for changes in the earth’s rotation by allowing for “leap seconds.” The International Bureau of Weights and Measures in France serves as the worldwide clearinghouse for information on measuring time.

Examples of how foreign jurisdictions have treated time standards include New Zealand’s adherence to the Time Act 1974, and the European Union’s standardization of Summer Time in 1996 (see Directive 2000/84/EC of the European Parliament and of the Council on “Summer Time Arrangements” for the most recent EU standard). Another example of a foreign jurisdiction’s laws related to time standards is the United Kingdom’s implementation of the above referenced EU directive through the Summer Time Order 2002 (a more complete description of the legal development of time standards in the UK is available here).

General Internet Resources on Time

The following select sites supply useful, mostly non-legal reference information related to time standards. These represent just a small sample of the many time standards resources available on the Internet.

Daylight Saving Time. This is one of the most thorough and informative sites on the Internet for information concerning DST. The site includes information on the history, laws and worldwide adherence to DST.

The National Institute of Standards and Technology. The NIST has put together an informative and authoritative site on time and time measurement. Included is information on time standards and measuring devices.

The Royal Observatory, Greenwich. The Royal Observatory is the home of the Prime Meridian of the World and the official UK source for information on time and astronomy. Of particular value are their online leaflets on timekeeping.

The Time Zone Converter. As its name suggests, this Internet site enables the user to convert from one time zone to another. There are many similar converters available on the Internet, however this one is up to date, comprehensive, and easy to use.

The Time Service Department, U.S. Naval Observatory. The USNO was established as the Department of Defense’ reference for time by DOD Directive 5160.51 (June 14, 1985) and SECNAV instruction 4120.20 (February 4, 1986). The site includes extensive information on time and time zones.

World Time Zones. This is a useful resource for locating information on time zones throughout the world. The site includes maps and other useful tools for determining the time and time zones on a global basis.


Since Congress enacted the Uniform Time Act in 1966 the United States and its territories have adopted and observed uniform time within nine specified time zones. Although each state is permitted to opt-out of the act, the overall result of this and subsequent legislation has been a more logical and systematic pattern of time standards throughout the country. The formalization of Daylight Saving Time in the act has also benefited the country both economically and environmentally through reductions in energy expenditure. However it would be wrong to assume that the final word on the law of time standards has been written. Inevitably we will continue to see incremental changes to the time zones and possibly even changes to the adoption and application of Daylight Saving Time. It would therefore appear that not only time, but also the laws that govern time standards, wait for no one.

Posted in: Features, Time