May 24, 2001


Mr. Chairman and Members of the Committee:

I am pleased to appear before you today to discuss the energy conservation potential of daylight saving time.

Part of my testimony today concerns U.S. Department of Transportation (DOT) studies of the effect of extending daylight saving time. I want to note that these studies are over 25 years old and were limited in scope. Congress captured many of the benefits identified in our studies in the legislative changes to daylight saving time enacted in 1986. There have been dramatic changes in lifestyle and commerce since we completed our studies that raise serious questions about extrapolating conclusions from our studies into today’s world.

Time observance affects almost every aspect of life and any proposed time change will have many consequences beyond any impacts on energy conservation. Any change needs to be carefully and fully considered at a national level after consultation with all the affected constituencies. Because of the impacts on transportation scheduling and telecommunications, any change needs to be made well in advance with plenty of public notice both in the U.S. and worldwide. Before taking any legislative action, we suggest that further study and consultation with affected groups is needed.

Current Statutory Requirements

The Uniform Time Act, as amended, gives the Secretary of Transportation two different responsibilities concerning time observance. First, the Secretary has authority to change a time zone boundary if he or she finds that such a change would "suit the convenience of commerce." Under DOT procedures, the Department only begins a time zone change rulemaking proceeding upon the request of a State or local jurisdiction. Normally, DOT holds one or more hearings in the area and provides 60 days for the public to comment in writing to the docket.

Second, the Secretary has responsibility to make sure that states that choose to observe daylight saving time begin and end on the Congressionally-mandated dates, which are the first Sunday in April to the last Sunday in October. A State may, however, exempt itself from daylight saving time observance and observe standard time year-round. If a State is in two time zones, it may observe daylight saving time in the portion of the state that is in one time zone and standard time in the other portion of the state. Currently, Arizona, Hawaii, the Eastern Time Zone portion of Indiana, Puerto Rico, the Virgin Islands, American Samoa, and Guam do not observe daylight saving time.

There are nine time zones in the United States, and four in the contiguous 48 States. When a State observes daylight saving time, it is the equivalent of moving one time zone to the east.

History of DST

The United States observed Daylight Saving Time during World War I, and year-round daylight saving time during World War II. In the post war periods, States and local jurisdictions were free to observe, or not observe, daylight saving time, beginning and ending on any dates they chose. During this period, there was a "crazy quilt" system of observance in which you could drive less than 100 miles and change back and forth in time observance many times.

Because of the widespread confusion and detrimental impacts on commerce, Congress adopted the Uniform Time Act of 1966. The Act provided national uniformity for the beginning and ending dates of daylight saving time, an "opt-out" provision for any State that does not want to observe, and an enforcement mechanism whereby DOT may go into Federal District Court to obtain an injunction against any jurisdiction not observing the correct time.

In response to the oil embargo in the early 1970s, Congress enacted the Emergency Daylight Saving Time Energy Conservation Act of 1973. As a result, in 1974, virtually all of the U.S. observed daylight saving time from January 6 to October 27, and in 1975, from February 23 to October 26.

Extended daylight saving time had very different impacts in different parts of the country. Its popularity also varied widely among different age groups and geographic locations. Most people opposed daylight saving time in winter, especially in January and February because it resulted in very late sunrises. Many parents were concerned about their children waiting for morning school buses in the dark as a result of any extension of daylight saving time. Others opposing daylight saving time included parents of young children who found it difficult during the transitional periods to get their children to sleep; members of some religious faiths, whose observances are tied to sunrise and sunset; and farmers.

In response to a Congressional request in the early 1970s, DOT prepared several comprehensive studies of the effect of extending daylight saving time from the last Sunday in April to the first Sunday in March. As I will discuss in a moment, the studies found that extending daylight saving time into March would provide modest energy savings, reduce traffic fatalities, reduce crime and provide afternoon light for recreation and chores.

After a decade of discussions and Congressional hearings, the most recent change to national daylight saving time observance occurred in 1986 when Congress changed the beginning date of daylight saving time from the last Sunday in April to the first Sunday in April.

To put this in an international perspective, most other countries in the world that are not located near the equator observe daylight saving time. Countries that are close to the equator do not have large seasonal variations in daylight and generally have little need for daylight saving time. Most of the Canadian provinces and Mexico begin and end daylight saving time on the same dates as the U.S. The European Union begins daylight saving time a week earlier on the last Sunday in March and ends at the same time as the United States.


Findings of the DOT Studies

Let me now briefly summarize the technical findings regarding daylight saving time benefits. The studies are over twenty-five years old and have not been updated.

Energy Savings

Our 1975 study concluded that daylight saving time might result in electricity savings of 1 percent in March and April, equivalent to roughly 100,000 barrels of oil daily over the two months. These savings were calculated from Federal Power Commission data for only four daylight saving time transitions -- in the winter, spring and fall of the 1974 - 1975 experiment. Due to the limited data sample, the findings were judged "probable", rather than conclusive. Theoretical studies of home heating fuel consumption identified small savings due to daylight saving time. No potential increases in travel demand and gasoline use due to daylight savings time were identified at that time. The lack of actual data precluded an estimation of net daylight saving time energy savings.

Traffic Fatalities

With respect to traffic fatalities, we were able to identify a 0.7 percent reduction due to daylight saving time in March and April 1974 compared to the comparable months in 1973 when we were under standard time. At the time, DOT analysts believed that these estimates were conservative and that their calculations understated the real reduction due to daylight saving time, which they judged to be on the order of 1.5 percent to 2 percent.

School-Age Children Safety

Following the first-year's experiment with year-round daylight saving time in 1974, we recommended that only March and April be included in the second year's experiment because of the public's concern over the safety of children traveling to school in dark mornings. Results of public opinion polls conducted in 1974 showed that 38 percent of respondents expressed concern for school-age children's safety during year-round daylight saving time compared to 7 percent of respondents concerned with the issue during the 1975 March-April experiment.

Our final study contained results of both the Department of Transportation and the National Safety Council studies indicating that for the January-April 1974 period (i.e., under daylight saving time), school-age children were not subject to greater involvement in fatal accidents than the general population at any period of the day. A 1976 study of school age fatalities performed by the National Bureau of Standards (NBS) used the same database as the Department of Transportation, but analyzed only a subset of the data and employed different statistical techniques. The National Bureau of Standards concluded that morning school-age children fatalities increased in January and February 1974 when daylight saving time was being observed, compared to the same period in 1973 when daylight saving time was not observed. No comparable increase in morning fatalities, however, was found for the March and April period. While the increase was statistically significant, the National Bureau of Standards judged it impossible to attribute it to daylight saving time or to some other factor (such as weather) or combination of factors. Because of the Bureau's findings, the Department subsequently took the position that daylight saving time in January or February might possibly increase school age fatalities in the morning.


With respect to the incidence of crime, study of daylight saving time impacts on the incidence of crime revealed reductions in violent crimes of 10 to 13 percent in Washington, D.C. throughout a 3-year period. Due to time constraints, only data for Washington, D.C. and Los Angeles were obtained for analyses. The data for Los Angeles were not sufficiently detailed to reveal a daylight saving time effect.

Changes in School Hours

The Department of Health, Education and Welfare advised that only a small number of schools in two Midwest and Western States adjusted school hours during March and April 1975 as a consequence of daylight saving time.

Other Effects

There were no measurable effects of daylight saving time reported by Federal agencies in the areas of agriculture, labor, and Federal park and recreational activities. Neither were there any reported effects on domestic or international commerce, with the exception of opposition to year-round daylight saving time by the construction industry, which favors an April through October period.

The Federal Communications Commission (FCC) reported that daylight saving time caused audience losses of 2.5 percent of AM daytime radio stations from January through April 1974 and 1.5 percent during March and April 1975. Since the Commission's primary concern was daylight saving time's curtailment of AM morning radio service to listeners in certain areas of the country served by approximately 500 daytime stations operating on U.S., Canadian and Mexican clear channels, it supported the traditional six-month daylight saving time system or the enactment of specific provisions enabling the FCC to take remedial steps as appropriate.

As part of the 1970s studies, the Governors of the twenty-five States bordering or divided by time zone boundaries were asked whether these boundaries should be changed. It is significant that even though these States experience the latest in daylight saving time sunrises, the Governors, with one exception, favored retaining the present time zone boundaries. The exception advocated having only two continental time zones. Based on this survey, the Department did not recommend any change in the existing time zone boundaries.


Potential Impacts of a Change in Observance

There are a number of possible different daylight saving time observances. Another possibility is to move whole time zone boundaries to the west, which, in effect, would give those, changed areas year-round daylight saving time. Each has benefits and drawbacks.

There are a number of potential anomalies to some of the ideas being considered. Arizona currently does not observe daylight saving time. If California, or all of the Pacific Time Zone states, observes "double daylight saving time" while Arizona remained on Mountain Standard Time, those states would be one hour earlier than Arizona. A portion of Idaho is in the Pacific Time Zone, but is not covered by pending legislation that would allow west coast states to make whatever changes to time observance they deem necessary. Finally, a small portion of Oregon is in the Mountain Time Zone.

Based on historic experience, the Department believes that it is critical to have national uniformity for daylight saving time observance to prevent confusion and to facilitate commerce and communications. Under the current system, an area either observes daylight saving time on the federally-mandated dates or stays on standard time year-round. Before the Uniform Time Act of 1966, one could never be sure, especially in advance, what dates a jurisdiction might be observing. Clear and consistent time observance is crucial for maintaining bus, train, and airline schedules. In addition, consistent time schedules and observance are critical in assuring railroad safety because the same tracks often are used for trains heading in both directions. Consistency has become more important over the years with globalization, "just in time" delivery, and the widespread use of computer programs with embedded daylight saving time changeover dates.

Any change requires adequate lead-time and notice to accommodate transportation, telecommunications, and other schedules. Time observance also has important consequences in many contracts and agreements. Finally, we need to be mindful of impacts on international trade and commerce.

Before making changes to daylight saving time, we urge the Congress to consider the costs and benefits of such changes. As I have noted, DOT’s studies are over 25 years old. New studies must consider impacts on uniformity, impacts on coordination of transportation and commerce, impacts on transportation safety, and net energy impacts. The studies must consider the impact of changes on electrical lighting use, heating energy use, air conditioning use, and transportation energy use, including the potential for increased travel demand resulting from more evening daylight and increased gasoline use.

This concludes my prepared remarks. I would be happy to answer any questions that you might have.