Saturday, March 10, 2007

Are we really saving in daylight savings time

On August 8, 2005, President George Bush signed the Energy Policy Act of 2005. Part of this act changed the dates for daylight saving time (DST) in the United States. Starting this year, DST will begin on the second Sunday of March (March 11), and end on the first Sunday of November (November 4): This change means that in 2007, 245 out of 365 days (or more than two thirds of the year) will be in daylight saving time. But why?

Supporters claim it will save the equivalent of 10,000 barrels of oil per day. But, this figure is based on U.S. Department of Energy statistics from the early 1970s, and many question the accuracy and relevancy of statistics from 30+ years ago.

How do we benefit from daylight saving time?
The idea behind moving the clocks twice a year is to take better advantage of the sun’s natural electricity (or light). Most of us get out of bed after the sun has risen and go to bed after it has set. But what if the sun rose and set later? When we spring forward and fall back, we’re not really “saving” time; we’re just giving up a little sun in the morning and adding it to the evening. So will we better utilize the sun’s illumination during this new-found sunlight?

Later sunsets cause people to get out and do more in the evenings. Some argue that this results in an increase in our gasoline consumption as we drive around more during the lighter evenings. And if it’s darker in the morning, doesn’t that mean more electricity will be needed to get ready for school and work?

Remember when?
In 1973, there was a sudden and unpredicted interruption in the supply of petroleum to the world. The result was alarming, with gas stations out of gas, long lines at the gas pumps, and people unable to use their cars. In response to “The Energy Crisis,” daylight saving time in the US was hastily begun much earlier, in both 1974 and 1975. In 1974, it started on the first Sunday of January (January 6), and in 1975 on the last Sunday of February (February 23).

It sounded like a good idea at first. The rationale was that the normally dark and dreary winter afternoons and evenings would be made a little brighter, the sun would set an hour later, and energy that might otherwise be used to light homes and offices in the late-day hours would be conserved. In addition, some believed that if we had more daylight at the end of the day, we would have fewer traffic accidents.

Nights bright, but mornings dark.
However, having the sun set an hour later also meant that it rose later, a side-effect that apparently did not “dawn” on many folks until after the time change went into effect. The direct result for many was unacceptably dark mornings. In 1974, some cities in the western part of their time zones, like Detroit, Michigan and Boise, Idaho, didn’t see the sun rise until after 9:00 a.m. Mothers found themselves sending children armed with flashlights off to the school bus. The experiment quickly ended and in 1976 the start of DST was returned to April.

Here we go again!
The famed philosopher and novelist George Santayana once wrote: “Those who cannot learn from history are doomed to repeat it.” Apparently, not many lawmakers today remember the lessons of more than three decades ago.

Is safety on our roads being compromised?
One of the chief reasons the extended DST was quickly repealed in the mid-1970s was because there was an increase in school bus accidents in the morning. Additionally, in an independent study of traffic accidents throughout Canada during the early 1990s, Stanley Coren of the University of British Columbia found an eight percent spike in traffic accidents on the Mondays after clocks were moved ahead. Coren attributed the spike to the lost hour of sleep. Others suspect that the changes in light levels when clocks are pushed forward and moved back confuse drivers in their regular commutes. Still others suspect that people hurry because they looked at an incorrect clock and then discovered that they are late.

A significant issue raised by the DST extension is that it will require a reconfiguration of virtually every computer in the U.S. Your home or office computer is programmed to automatically adjust for DST, based on static tables stored directly on the computer itself. In order to change the dates on which the automatic jump to or from DST occurs, the tables must be modified.

Lastly, daylight saving time has always been particularly unpopular among those in the agricultural industry, because animals do not observe it, but follow the sun instead.

Farmers’ Almanac Proposes a BETTER Schedule
It is not very likely that we’ll do away with daylight saving time anytime soon, but we at the Farmers’ Almanac believe we have a better method for scheduling it. If we wish to utilize DST to its fullest, the primary aim should be to capture the maximum amount of daylight without causing more morning darkness.

Civil twilight becomes an important consideration in this regard. Astronomers define civil twilight as: “That interval prior to sunrise or just after sunset in which enough sky illumination still exists (barring dense cloud cover) to carry on normal work out-of-doors.” While the duration of civil twilight varies during the course of a year, at latitude 40º North—which is the median latitude for the contiguous U.S.—it generally starts about a half hour before sunrise and ends about a half hour after sunset. If we assume that most people arise to start their normal work or school days at 6:00 a.m., daylight saving time should be implemented when the start of civil twilight will coincide with that rising time. Sunrise (and full daylight) would then come a half hour later. Civil twilight at 5:00 a.m. standard time, or 6:00 a.m. daylight saving, occurs during the first week of April.

For example: If you look at the table below of sunrise and sunset times for Philadelphia, Pennsylvania (Latitude 39.9º N, Longitude 75.1º W) listed in Eastern Standard and Daylight Time, to take best advantage of Civil Twilight, we should “spring” ahead on April 7th. Under the old rules, DST started from April 1 to April 7.

1 comment:

morningsunshine said...

I believe that somewhere in there was a whole year that they decided to go by DST... and it was an unmitigated disaster. but.....

since lawmakers are more concerned with the NOW than the THEN, we are all doomed to repeat their mistakes.

ps - I like the new look, except for one thing - I have to high light the text in order to read it.

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