Starting next year, you will "spring forward" earlier and "fall back" later.

Starting next year, you will "spring forward" earlier and "fall back" later. The change called for by the Energy Policy Act of 2005 is designed to save energy. Beginning in 2007, daylight-saving time (DST) will start on the second Sunday in March and change back to standard time on the first Sunday in November. The U.S. Department of Energy will study the effect of the daylight-saving extension on energy use, and Congress can go back to the current schedule if there are no significant energy savings. Currently, DST begins the first Sunday in April and ends the last Sunday in October.

Daylight-saving time, or what most of the world calls "Summer Time," is thought to reduce energy use by allowing better use of natural lighting, since it gives people an hour more of sunlight in the evening. Also, people are more likely to be involved in outdoor activities, reducing the time they're inside using electricity. Other potential benefits include reduction in traffic accidents and crime.

Congressman Fred Upton (R-Mich.), the co-sponsor of the daylight-saving amendment to the energy bill, said, "Extending daylight-saving time makes sense, especially with skyrocketing energy costs. My daylight-saving amendment is one small piece of the overall energy package, and with oil at $60 a barrel and gas at $2.50 a gallon, every bit of conservation helps."

The United States last went on extended DST to save energy following the 1973 Arab oil embargo. Congress extended DST in 1974 and 1975. In a study of the period, the U.S. Department of Transportation found that observing DST in March and April saved the energy equivalent of 10,000 barrels of oil, or about a one percent per day savings. It also concluded that DST had prevented about 2,000 traffic injuries and 50 fatalities in March and April of 1974 and 1975.

It's difficult to know whether the daylight- saving extension starting next year will have similar results, since energy use patterns have changed. For example, more people have air conditioning now than in the 1970s, and an extra hour of sunlight can mean an extra hour of air conditioning.

Daylight-saving was first put into practice in 1916 by Germany and then the United Kingdom to save fuel during World War I. The United States implemented DST in 1918, but the unpopular law was later repealed. Daylight-saving was brought back in 1942, again to reduce fuel consumption during wartime.

After the war, federal law no longer mandated DST. States, cities and counties could establish their own daylight-saving plans, and most did. Without federal standards, the country was a patchwork of different times. To prevent this confusion, the U.S. Uniform Time Act of 1966 established dates for the beginning and end of DST, but said that states could exempt themselves from DST. Arizona (except for the Navajo Nation) and Hawaii do not observe DST. Until this year, Indiana was the only other holdout, with some parts of the state observing DST and some not.

One thing that's sure about the new DST schedule is that it will make kids happy by giving an hour more of light on Halloween.

For further reading:

Daylight-Saving (WebExhibit online museum) — http://webexhibits.org/daylightsaving/

Seize the Daylight: The Curious and Contentious Story of Daylight-Saving Time  by David Prerau