A new study estimates that switching the country to permanent daylight saving time would add about 2 billion dark-morning school commutes every year compared with how clocks work now. The research, led by scientists at the University of Washington, used real school data from 14 states to count school trips occurring before sunrise under a year-round daylight saving system.
The findings, published Thursday in Current Biology, drew on school start-time, enrollment and location data from 16,093 schools. Researchers calculated that across those 14 states alone, permanent daylight saving time would add roughly 356 million additional child-days of pre-sunrise travel to school. Guadalupe Rodríguez Ferrante, the study's lead author and a University of Washington postdoctoral scholar in biology, said the broader national estimate of 2 billion-plus extra dark commutes assumed students leave home around 8 a.m., a detail she said likely undersells the real impact. “Our calculation is likely an underestimation of the real number,” Rodríguez Ferrante said, according to UW News.
Which States Would Feel It Most
The study found the effects would not be spread evenly. Georgia would see the largest increase among the states studied, with about 71 million additional dark-morning trips, while Washington would see nearly 35 million more, per the same UW News account. Mississippi and Alabama would each see dark school trips balloon from about 2 million under the current system to more than 20 million under permanent daylight saving time.
Communities sitting on the western edge of a time zone, and schools with earlier start times, would face some of the biggest swings in dark commutes, the research found, since sunrise there already comes later in the morning. The Spokesman-Review reported that students near the western edge of the Pacific time zone, such as those in Port Angeles, would be more affected than students near its eastern edge, like Walla Walla. For Washington's roughly 1.05 million public school students, the outlet reported the study estimated dark commutes could rise from about 20 million to 55 million a year.
Darkness and Crash Risk
Beyond commute counts, the study team examined U.S. traffic collision data. Fatal crashes involving school-age pedestrians on school-year mornings were roughly twice as likely during darkness. The researchers were careful to note that this finding does not establish how many additional crashes permanent daylight saving time itself would cause, writing that the safety consequences of the proposed change remain unquantified.
Horacio de la Iglesia, senior author of the study and a University of Washington biology professor, framed the tradeoff in blunt terms. “Nobody wants their kids to go to school in the dark,” de la Iglesia said. Morning light helps set the body's circadian clock, which in turn helps regulate sleep, mood and appetite, according to the UW News release.
Where the Policy Stands
Permanent daylight saving time would shift the clock to favor more evening daylight at the expense of winter morning light. Nineteen states, including Washington, have already preapproved the switch contingent on federal action, UW News reported. At the federal level, the Sunshine Protection Act would make daylight saving time permanent and end the twice-yearly clock change; the bill, as described on its Congress.gov page, would establish daylight saving time as the new permanent standard. As FOX 10 Phoenix reported, the U.S. House passed the measure on July 14, 2026, and it remains pending in the Senate.
