Order Code 98-99 C
Updated December 17, 2002
CRS Report for Congress
Received through the CRS Web
Daylight Saving Time
Heidi G. Yacker
Information Research Specialist
Information Research Division
Currently, in most parts of the United States, timepieces are moved forward one
hour in the spring and back one hour in the fall to provide an extended daylight period
during the summer months. This is known as Daylight Saving Time (DST). Much
debate and many changes led to this present practice. Questions regarding DST and
suggestions for changes persist. This report provides a brief history of the issues
surrounding DST, an outline of the legislation that created and modified it, and a list of
references to more discussions. Whenever the law or regulations governing DST change
in the United States, this report will be updated.
Development of Daylight Saving Time
Daylight Saving Time (DST) is
Currently, Daylight Saving Time (DST) is
not a new concept. In 1784, when
observed in the United States from 2:00 a.m. on
Benjamin Franklin was Minister to
the first Sunday in April until 2:00 a.m. on the
France, an idea occurred to him: in
last Sunday in October. The following states
that part of the year when the sun
and territories do not observe DST: Arizona,
rises while most people are still Hawaii, part of Indiana, American Samoa,
asleep, clocks could be reset to allow Puerto Rico, and the Virgin Islands.
an extra hour of daylight during
waking hours. He calculated that
French shopkeepers could save one million francs per year on candles. In 1907, William
Willett, a British builder, Member of Parliament, and fellow of the Royal Astronomical
Society, proposed the adoption of advanced time. The bill he introduced was reported
favorably, asserting that DST would move hours of work and recreation more closely to
daylight hours, reducing expenditures on artificial light. There was much opposition,
however, and the idea was not adopted.
During World War I, in an effort to conserve fuel, Germany began observing DST
on May 1, 1916. As the war progressed, the rest of Europe adopted DST. The plan was
not formally adopted in the United States until 1918. “An Act to preserve daylight and
provide standard time for the United States” was enacted on March 19, 1918 (40 Stat
Congressional Research Service ˜ The Library of Congress
450). It established both standard time zones and set summer DST to begin on March 31,
1918. The idea was unpopular, however, and Congress abolished DST after the war,
overriding President Wilson’s veto. DST became a local option and was observed in
some states until World War II, when President Roosevelt instituted year-round DST,
called “War Time,” on February 9, 1942. It lasted until the last Sunday in September
1945. The next year, many states and localities adopted summer DST.
By 1962, the transportation industry found the lack of nationwide consistency in time
observance confusing enough to push for federal regulation. This drive resulted in the
Uniform Time Act of 1966 (P.L. 89-387). The Act mandated standard time within the
established time zones and provided for advanced time: clocks would be advanced one
hour beginning 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. States were allowed to exempt themselves from DST
as long as the entire state did so. If a state chose to observe DST, the time changes were
required to begin and end on the established dates. In 1968, Arizona became the first state
to exempt itself from DST. In 1972, the Act was amended (P.L. 92-267), allowing those
states split between time zones to exempt either the entire state or that part of the state
lying within a different time zone. The newly created Department of Transportation
(DOT) was given the power to enforce the law. Currently, the following do not observe
DST: Arizona, Hawaii, the part of Indiana in the eastern time zone, American Samoa,
Puerto Rico, and the Virgin Islands.
During the 1973 oil embargo by the Organization of Petroleum Exporting Countries
(OPEC), in an effort to conserve fuel Congress enacted a trial period of year-round DST
(P.L. 93-182), beginning January 6, 1974, and ending April 27, 1975. From the
beginning, the trial was hotly debated. Those in favor pointed to the benefits of increased
daylight hours in the winter evening: more time for recreation, reduced lighting and
heating demands, reduced crime, and reduced automobile accidents. Opposition was
voiced by farmers and others whose hours are set by the sun rather than by the clock.
With later sunrises and sunsets, they were unable to arrive at work on time after morning
activities or participate in evening activities. Another major concern was children leaving
for school in the dark. The Act was amended in October 1974 (P.L. 93-434) to return to
standard time for the period beginning October 27, 1974, and ending February 23, 1975,
when DST resumed. When the trial ended in 1975, the country returned to observing
summer DST (with the aforementioned exceptions).
DOT, charged with evaluating the plan of extending DST into March, reported in
1975 that “modest overall benefits might be realized by a shift from the historic six-month
DST (May through October) in areas of energy conservation, overall traffic safety and
reduced violent crime.” However, DOT also reported that these benefits were minimal
and difficult to distinguish from seasonal variations and fluctuations in energy prices.
Congress then asked the National Bureau of Standards (NBS) to evaluate the DOT
report. NBS found no significant energy savings or differences in traffic fatalities. It did
find, however, statistically significant evidence of increased fatalities among school-age
children in the mornings during the test period, although it was impossible to determine
if this was due to DST.
During the 96th, 97th, and 98th Congresses, several bills to alter DST were
introduced, and the debate continued. Final action came in the 99th Congress with the
enactment of P.L. 99-359, which amended the Uniform Time Act, changing the beginning
of DST to the first Sunday in April and having the end remain the last Sunday in October.
Since then, other legislation has been introduced concerning DST; none of this legislation
has been enacted.
Changing an Area’s Time Zone or Moving an Area On or Off DST
Moving a state or an area within a state from one time zone to another requires either
a public law or a regulation issued by DOT. In the latter case, DOT recommends the
following procedure. The request should be submitted by the highest political authority
in the area in question. For example, the governor or state legislature generally makes the
request for a state or any part of the state; a board (or boards) of county commissioners
may make a request for one or more counties. If the request is made by a legislative body,
it must be accompanied by certification that official action has been taken by that body.
The request should document evidence that the change will serve the convenience
of commerce in the area. The convenience of commerce is defined broadly to consider
such circumstances as the shipment of goods within the community; the origin of
television and radio broadcasts; the areas where most residents work, attend school,
worship, or get health care; the location of airports, railway, and bus stations; and the
major elements of the community’s economy.
The General Counsel of DOT considers the request and, if it is found that a time
zone change might benefit commerce, a proposed regulation is issued inviting public
comment. Usually a hearing is held in the area so that all sides of the issue can be
represented by the affected parties. After analyzing the comments, the General Counsel
decides either to deny the request or forward it to the Secretary of Transportation. If the
Secretary agrees that the convenience of commerce would benefit, the change is instituted,
usually at the next changeover to or from DST.
Under the Uniform Time Act, moving an area on or off DST is accomplished
through legal action at the state level. Some states require legislation while others require
executive action such as a governor’s executive order. Information on procedures
required in a specific state may be obtained from that state’s legislature or governor’s
office. Although it may exempt itself, if a state decides to observe DST, the dates of
observance must comply with federal legislation.
April 13, 1966. Uniform Time Act of 1966. Established uniform standard time to
be observed in established time zones. The standard time would be advanced one hour
within each time zone beginning at 2:00 a.m. on the last Sunday in April and turned back
one hour beginning at 2:00 a.m. on the last Sunday in October. States were allowed to
exempt themselves as long as the entire state was exempted.
March 30, 1972. Uniform Time Act Amendments. Allowed states split by time
zone boundaries to exempt the entire state or that part of the state in a different time zone
from DST. The states affected are: Alaska, Florida, Idaho, Indiana, Kansas, Kentucky,
Oregon, Nebraska, North Dakota, South Dakota, Tennessee, and Texas.
December 15, 1973. Emergency Daylight Saving Time Energy Conservation Act of
1973. Established a trial period for year-round DST beginning January 6, 1974, and
ending April 27, 1975.
October 5, 1974. Emergency Daylight Saving Time Energy Conservation Act
Amended. P.L. 93-182 to restore standard time from November 1974 through
October 8, 1986. Fire Prevention and Control Authorizations Act. Amended the
Uniform Time Act of 1966 to begin DST on the first Sunday in April. The end of DST
would remain at the last Sunday in October.
Bartky, Ian R., and Elizabeth Harrison. “Standard and Daylight-Saving Time.” Scientific
American, vol. 240 (May 1979), pp. 46-53.
California Energy Commission. Effects of Daylight Saving Time on California Electricity
Use. Sacramento: The Commission, 2001. 36 p.
Coren, Stanley. “Daylight Savings Time and Traffic Accidents.” New England Journal
of Medicine, vol. 334 (April 4, 1996), p. 924.
——. “Dr. Coren Replies” [to article by Vincent cited below]. New England Journal of
Medicine, vol. 339 (October 15, 1998), pp. 1167-1168.
Ferguson, Susan A., et al. “Traffic Accidents and Daylight Saving Time.” New England
Journal of Medicine, vol. 335 (August 1, 1996), p. 335.
——. Reduction in Pedestrian and Vehicle Occupant Fatal Crashes with Daylight
Saving Time (Arlington, VA: Insurance Institute for Highway Safety, 1993). 15 p.
U.S. Congress. House. Committee on Energy and Commerce. Daylight Saving
Extension Act of 1985. Report to accompany H.R. 2095, including cost estimate of
the Congressional Budget Office. 99th Congress, 1st session. H.Rept. 99-185.
Washington: GPO, 1985.
—– Committee on Science. Energy Conservation Potential of Extended Daylight Saving
Time. Hearing. 107th Congress, 1st session. May 24, 2001.
U.S. Department of Transportation. The Daylight Saving Time Study. 2 vols. A report
to Congress. Washington: GPO, 1975.
Vol. 1, Final Report of the Operation and Effects of Daylight Saving Time.
Vol. 2, Supporting Studies: Final Report of the Operation and Effects of Daylight
U.S. National Bureau of Standards. Review and Technical Evaluation of the DOT
Daylight Saving Time Study. Prepared for the Chairman, Subcommittee on
Transportation and Commerce, Committee on Interstate and Foreign Commerce,
U.S. House of Representatives. Washington: GPO, 1976. PP. 125-351.
Appendix to hearing on the Daylight Saving Time Act of 1976, 94th Congress,
2nd session. Serial no. 94-109.
Vincent, Alex. “Effects of Daylight Saving Time on Collision Rates.” New England
Journal of Medicine, vol. 339 (October 15, 1998), pp. 1167-1168.
Calls into question results of study by Coren (New England Journal of
Medicine, 1996), cited above.