Permanent DST would lift Mississippi's dark school trips from 2 million to over 20 million

Making daylight saving time permanent in the United States would add more than a billion school commutes in the dark each year, according to University of Washington researchers writing October 29 in Current Biology. In Mississippi and Alabama, which start school before 8 a.m. on average, dark trips would jump from about 2 million to more than 20 million in each state.

The study puts a number on a cost that rarely comes up in the debate over the Sunshine Protection Act: the bill keeps evenings brighter by taking that hour of light out of winter mornings, when children travel to school.

How the researchers counted dark mornings

The US House passed the bill in July 2026, and it is stalled in the Senate. Nineteen states, including Washington, have already approved the change if federal law allows it. The team took 14 of those states and combined each school's listed start time, its enrollment and its latitude and longitude with local sunrise times, then added up every trip that would begin before sunrise.

Across those 14 states, the count came to about 356 million additional pre-sunrise commutes, according to Cell Press. Georgia saw the largest increase, about 71 million trips, and Washington would see almost 35 million. Extending the method to the whole country produced more than 2 billion extra dark commutes, while the paper's own title states the conclusion more cautiously as over a billion.

The researchers think the figure is low. They assumed children leave home around 8 a.m., and many arrive earlier for breakfast programs. "That's pretty late, so our calculation is likely an underestimation of the real number," said lead author Guadalupe Rodríguez Ferrante, a UW postdoctoral scholar.

Who would feel it most

Towns at the western end of a time zone, Forks in Washington among them, fare worst, along with districts that ring the first bell early. Some districts that never see a dark commute today would see them routinely, Rodríguez Ferrante said.

The team also reviewed a decade of US fatal crash records. Fatal crashes in which the pedestrian was a child of school age were roughly twice as likely on dark mornings as after sunrise, according to the University of Washington. The researchers say children who walk, wait at bus stops or arrive early for school breakfast, which disproportionately serves lower-income families, carry most of that risk.

The country has tried this once

The US switched to year-round daylight time in January 1974 and abandoned it that October, partly over public concern about dark winter mornings and children walking to school, the researchers noted. None of today's students and few of their parents have lived through a winter on permanent DST.

Senior author Horacio de la Iglesia, a UW biology professor, argues that pushing school start times later would not fix the problem, since shifting every schedule an hour later simply recreates standard time. The team's preferred option is permanent standard time, which they say keeps children's biological, solar and social clocks best aligned. Whether the Senate takes up the bill again has not been announced.