Daylight saving time

Daylight saving time (also called DST, or summer time) is the portion of the year in which a region's local time is advanced by (usually) one hour from its official standard time. It is most common in temperate regions.

Rationales for DST

One of the major reasons given for observing DST in the United States is energy conservation. Theoretically, the amount of residential electricity needed in the evening hours is dependent both on when the sun sets and when people go to bed. Because people tend to observe the same bedtime year-round, by artificially moving sunset one hour later, the amount of energy used is theoretically reduced. United States Department of Transportation studies showed that DST reduces the country's electricity usage by one percent during each day DST is in effect.

Related Topics:
United States - United States Department of Transportation

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Part of the reason that it is normally observed in the late spring, summer, and early autumn is because during the winter months the amount of energy saved by moving sunset one hour later is negated by the increased need for morning lighting by moving sunrise by the same amount. During the summer most people would wake up after the sun rises, regardless of whether daylight saving time is in effect or not, so there is no increased need for morning lighting to offset the afternoon energy savings.

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Another perceived benefit of DST is increased opportunities for outdoor activities. Most people plan outdoor activities during the increased hours of sunlight. Other benefits cited include prevention of traffic injuries (by allowing more people to return home from work or school in daylight), and crime reduction (by reducing people's risk of being targets of crimes that are more common in dark areas).

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When the U.S. went on extended DST in 1974 and 1975 in response to the 1973 energy crisis, Department of Transportation studies found that observing DST in March and April saved 10,000 barrels of oil a day, and prevented about 2,000 traffic injuries and 50 fatalities saving about U.S. $28 million in traffic costs. http://www.boulder.nist.gov/timefreq/general/daylightsavingtime.html

Related Topics:
1974 - 1975 - 1973 energy crisis - $

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