E-Mail This Article to a Friend Lighten up Author David Prerau illuminates daylight saving time BY TAMARA WIEDER

IT HAPPENS THE first Sunday each April, and again the last Sunday of every October. When daylight saving time begins, we dutifully set our clocks ahead an hour, then set them back an hour when it ends seven months later — only to do it all again the next year. Other than to lament winter’s lack of daylight, and herald the arrival of more of it every spring, few of us think much about this biannual manipulation of time.

But David Prerau has thought about it, a lot. And all of his thinking has led to his new book, Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time (Avalon). In it, Prerau, a local computer scientist who has co-authored several reports to Congress on the subject of daylight saving time, recounts the history of the movement to regulate daylight hours, starting with Benjamin Franklin’s development of the idea in the 1700s. Though on its surface, the concept of daylight saving time seems simple, its repercussions are felt the world over, from botched time bombs to barroom brawls, voter turnout to traffic safety. Think of that on Sunday, when you’re growling about losing an hour of sleep.

Q: How’d you get interested in this subject in the first place? It’s not exactly a common interest.

A: It’s actually very simple. I was working many years ago as a researcher for the US government, and I participated in what was probably the largest study ever on the effects of daylight saving time, because the government wanted to know whether we should have more of it. While I was doing this technical study, I got curious about the history of daylight saving time, and I asked the people involved and everyone else, and nobody seemed to know anything about it, so being the researcher I was, I started looking into it, and I found it had a long and interesting and contentious history going back to Benjamin Franklin in 1784, with a lot of fights along the way, and I also found a lot of anecdotes. So I started collecting all of this information, with the idea of someday putting it together in a book.

Q: Why did the government feel the need to do the study that you participated in?

A: This was in the 1970s, right after the Arab countries had put an oil embargo on the United States, and that led to the first peace-time energy shortage in the history of the United States. The government was trying to think of ways to save energy as quickly and painlessly as possible. Daylight saving time had been known from its beginning as something that saved energy. So the government put into place, as an emergency measure, extended daylight saving time, for two years. Part of the law to do that was to ask the US Department of Transportation, where I was working, to do a study to see what the impacts of extended daylight saving time were. So we looked into the impacts on things like energy, traffic accidents, commerce, and a lot of other areas, and we found in general, daylight saving time had a positive impact on almost every area.

Q: What surprised you most about the results of the study?

A: I was surprised to find that daylight saving time had an impact on radio stations. The reason is that radio transmissions go a lot further in the evening than in the daytime, in the dark versus the daytime, because the sun affects the ionosphere and changes the way the radio signals transmit. Because of that, you can have more stations in the daytime than in the evening and they won’t interfere with each other. So there’s a series of daytime-only stations, and these daytime-only stations, because of this physical limitation, are licensed to operate only from sunrise to sunset. Well, when you have daylight saving time, what it does is it pushes their hours of operation one hour later. Now, the problem is that most small stations serve a local audience, and their biggest money-making time is morning drive time. In the morning people want to know the local weather, the local traffic, and so on. In the evening they often listen to the network or the bigger stations to hear about the national situation. So by taking away an hour in the morning and adding it to the evening, stations lose their morning drive time, and therefore they lose money. And in addition to money, the FCC was actually more concerned about the fact that a lot of areas were losing their local information, about the traffic, about the farm prices, about all the other things. So that was an impact that I hadn’t thought about, but I thought it was a pretty interesting impact of daylight saving time.

Q: In the book you detail a lot of the unexpected ways that DST has affected and continues to affect the world. What are some of your favorite anecdotes?

A: In the 1950s and ’60s, there was no limitation on daylight saving time. There was no federal law, and each state or city or town could pass its own law about if they wanted daylight saving time — when they wanted it to start and when they wanted it to end. This led to a country-wide hodgepodge of times and confusion. In one year in Iowa, there were 23 different pairs of starting and stopping times used in that one state. So you can imagine that if you’re in one town, you might not even know when your town starts and ends daylight saving time, but you certainly wouldn’t know when the next town and the next town do. So of course that led to lots of confusion.

You also had, in the same era, a famous bus ride you could take from Steubenville, Ohio, to Moundsville, West Virginia, where you would go only 35 miles in the bus, and at each stop, if you wanted to keep your watch current to the time, because of going in and out of daylight saving time, you’d have to change your watch seven times in 35 miles.