Spring ahead, fall back. Daylight saving time begins Sunday, March 14, which means it’s time to turn clocks ahead an hour and gain an extra hour of daylight at the end of each day.

The new time begins officially at 2 a.m. Sunday, March 14. But many will probably turn their clocks ahead an hour when they go to bed Saturday night.

Time zones are regulated by the U.S. Department of Transportation. According to the Institute for Dynamic Educational Advancement, daylight saving time has been used in the United States and Europe since World War I.

“At that time, in an effort to conserve fuel needed to produce electric power, Germany and Austria took time by the forelock, and began saving daylight at 11 p.m. on April 30, 1916, by advancing the hands of the clock one hour until the following October.

“Other countries immediately adopted this 1916 action: Belgium, Denmark, France, Italy, Luxembourg, Netherlands, Norway, Portugal, Sweden, Turkey and Tasmania. Nova Scotia and Manitoba adopted it as well, with Britain following suit three weeks later, on May 21, 1916. In 1917, Australia and Newfoundland began saving daylight.”

In the United States, time zones were first created for the railroads by the Interstate Commerce Commission on Nov. 18, 1883, to expeditiously transport goods and travelers across the country. In 1967, time zone duties were transferred from the commission to the U.S. Department of Transportation.

During what the U.S. Naval Observatory called the “energy crisis years” in the 1970s, Congress enacted an early starting date, calling for daylight saving time to begin on Jan. 6 in 1974 and Feb. 23 in 1975. The following year, daylight saving time went back to a late-April start date. Beginning in 1986 and continuing through 2006, the start and end dates of daylight saving time remained consistent. Now those dates have changed, however, thanks to the Energy Policy Act of 2005.

In August 2005, the Energy Policy Act changed daylight saving time, effective last year, expanding daylight saving time by four or five weeks and keeping the country on that schedule for 65 percent of the year.

To synchronize clocks, the National Institute of Standards and Technology broadcasts the time from radio station WWVB. Its Web site also provides the exact time.

The NIST and the U.S. Naval Observatory are the country’s official time sources and both agencies contribute to the Coordinated Universal Time Scale maintained by the International Bureau of Weights and Measures. The NIST is responsible for providing the ultimate measurement reference for all physical quantities in the United States while the naval observatory provides time for navigation and military purposes.

Way before the federal government got involved in time, the Egyptians were establishing day and night parameters. According to the NIST, a sundial from 1300 BCE indicates that Egyptians determined a daily cycle of 10 hours of daylight, two hours of twilight and 12 hours of night. They also established a 365-day year, and their clock was similar to Oriental clocks. Minutes come from the Babylonians, circa 300 BCE, and their astronomical calculations.