The drive behind the switch was "to adjust daylight hours to when most people are awake and about," Mosley said.

Daylight saving time decreases the amount of daylight in the morning hours, so that more daylight is available during the evening.

Not everyone benefits from the daylight saving time change, Mosley conceded. Farmers and others who rise before dawn may have to operate in the dark a while longer before daybreak.

And some experts suggest that the extended hours implemented in 2007 to save energy won't actually do the trick. That's because people may use more electricity during the darker mornings, canceling out any savings from not using as much power at night.

Daylight saving time, however, can bring many benefits, Mosley said. Research has shown that more available daylight does decrease the number of traffic accidents, traffic fatalities, and incidences of crime.

Congress noted other advantages while updating legislation in 1986, including "more daylight outdoor playtime for the children and youth of our Nation, greater utilization of parks and recreation areas, expanded economic opportunity through extension of daylight hours to peak shopping hours and through extension of domestic office hours to periods of greater overlap with the European Economic Community."

[National Geographic]