In areas that practice Daylight Saving Time, or DST, the fall shift returns the clocks to "standard" timekeeping. In the United States, autumn time is standard in name only; since 2007, DST has occupied seven of the 12 months of the year.
The return to standard time in the fall is intended to set the clocks back to the timekeeping they would have been at without the "lost" hour imposed by DST. By setting the clocks back an hour, areas with limited fall and winter sunlight are (theoretically) able to enjoy an extra hour of daylight in the evening, when most people are home from work and likely to be active. The extra light is believed to reduce energy consumption, though studies have found mixed results from this.
Shifting away from DST has another effect: the 8-percent increase in traffic accidents reported on the Monday morning after the spring shift is exactly balanced by an 8-percent drop in accidents, presumably caused by sleep-deprived drivers, on the Monday following the "addition" of an extra hour in the fall. This difference may be the result, not of which hour the clocks show but of the disruption of changing sleep patterns for millions of people every year.