Clocks fell back to standard time less than a week ago, but a new study out of the University of Washington warns that a push in Congress to make daylight saving time permanent would send millions of American schoolchildren to class in the dark.
Researchers combined school enrollment figures, individual school start times and geographic coordinates across 14 of the 19 states that have already passed measures favoring permanent daylight saving time, then compared how many "dark" pre-sunrise school commutes students would face under a permanent shift against the current twice-a-year clock change. Nationwide, they estimate the switch would add at least a billion additional dark-morning trips to school each year. Washington state alone would see roughly 35 million more; Georgia, the largest increase among the states studied, about 71 million. In Mississippi and Alabama, where schools tend to start before 8 a.m., dark trips currently number roughly 2 million per state but would rise to more than 20 million each.
A traffic-safety link
The team, writing in the journal Current Biology, also cross-referenced U.S. traffic-collision records involving school-age pedestrians and found that fatal crashes were roughly twice as likely during dark morning hours as after sunrise. The authors are careful to note that comparison measures risk by time of day rather than directly proving how many additional crashes a change in the law would cause.
"You could call it the Sunshine Destruction Act," said Horacio O. de la Iglesia, a UW biology professor and the study's senior author, referring to the Sunshine Protection Act, the bill that would make daylight saving time year-round. The extra hour of evening light the bill promises, he said, comes directly out of the morning. "Nobody wants their kids to go to school in the dark."
"We were asking what's the cost for these children."
Guadalupe Rodríguez Ferrante, UW postdoctoral researcher and the study's lead author
Rodríguez Ferrante's team assumed, conservatively, that students leave for school around 8 a.m. — "that's pretty late," she said — meaning the billion-trip nationwide estimate is likely an undercount, since many children leave considerably earlier. The analysis also covers only the 14 states for which researchers had detailed school-level start-time data; five other states that have passed permanent-daylight-saving measures were not modeled in the same detail.
The House passed permanent-daylight-saving legislation earlier this year, but the bill has stalled in the Senate. Sleep researchers have long argued that morning light keeps the body's circadian clock properly synchronized, and the study's authors say a permanent shift to daylight saving time could undercut the sleep benefits that many districts have pursued by separately pushing high-school start times later. Supporters of the change counter that a single, stable time standard would eliminate the disruption that comes from changing clocks at all — a trade-off likely to keep surfacing as the Senate takes up the bill.
