Daylight-saving time starts Sunday

It is that time of year again when the clock watchers give way to the clock setters who try to remember which way to go when changing over to daylight saving time. This year the changeover dates are March 14 and Nov. 7.

It started with the railroads, the telegraph and the relatively high-speed, long-distance communications and travel that they facilitated. Before railroads, with their need to schedule stops accurately, each locality basically set its own time.

After 1883, the railroads divided the country into time zones and set the time in each zone, but it was not until 1918, when the Standard Time Act was passed, that it became law. The act also established daylight saving time, however it was repealed in 1919 while the time zones remained in the law.

After the national daylight saving time was repealed, it became a local matter. It was re-established nationally early in World War II, and was continuously observed from Feb. 1942 to Sept. 1945. During this time, it was also known as War Time. After the war, its use varied among states and localities. The Uniform Time Act of 1966 provided standardization in the dates of beginning and ending of daylight saving time in the U.S., but allowed for local exemptions from its observance. The act provided that daylight saving time began on the last Sunday in April and ended on the last Sunday in October, with the changeover to occur at 2 a.m., local time.

The changeover dates have changed through the years and daylight-saving time currently starts on the second Sunday in March and ends on the first Sunday in November. A mnemonic device, "Spring forward, fall back" is said to help people remember to move the time from 2 a.m. to 3 a.m., in the spring and from 2 a.m. to 1 a.m., in the fall.

Fortunately, most new digital devices have the ability to change the time automatically, depending on their operating system. For older digital devices, and analog ones, it is still a manual operation.

The United States Naval Observatory is the official source of time for the U.S. Department of Defense and a time standard for the entire United States. The Web site, http://www.usno.navy.mil/USNO, displays the master time and has links to software that can synchronize computers and other devices with Network Transfer Protocol to maintain precise time on systems all over the country.

The changeover is also a good way to remember to change the batteries in smoke alarms and carbon monoxide detectors while changing the time on their clocks.

"The semi-annual time changes are great reminders to change the batteries in smoke and carbon monoxide detectors," State Fire Marshal Randy Cole said. "Across the country, 80 percent of the children who die in home fires are killed in residences without a working smoke alarm. If people take the words 'change your clocks, change your batteries' to heart, we would reduce the number of home fire deaths in the United States."

Since most fire deaths occur at night, from 11 p.m. to 7 a.m., a working detector can help alert residents to dangers they might never notice before being overcome by them.

"The chance of surviving a fire increases 50 percent with a working smoke alarm," Cole said. "Having smoke detectors and CO detectors with fresh batteries are the best ways to protect your family in the event of a fire."

Cole recommends that Missourians regularly check smoke and CO detectors by pushing the test button, plan two escape routes from their homes and practice those escape routes with the entire family. Only 23 percent of U.S. families have developed and practiced a home fire escape plan.