A University of Washington research team found that adopting permanent daylight saving time nationwide would create at least 2 billion additional school trips in darkness, according to a study published October 29 in Current Biology.
The researchers examined school enrollment data, start times, and geographic coordinates in 14 of the 19 states that have already approved permanent daylight saving time measures. Permanent DST would push sunrise an hour later during winter months, leaving mornings darker from November through March.
In Washington state alone, the change would produce nearly 35 million additional dark school commutes. Georgia showed the largest increase at approximately 71 million additional dark trips. The team cautioned that the 2 billion figure may be too low, since many children travel to school earlier than the assumed 8 a.m. departure time used in nationwide calculations.
Traffic data revealed a safety concern. Fatal crashes involving school-aged pedestrians were roughly twice as likely to occur during dark mornings compared with after sunrise.
Horacio de la Iglesia, senior author and a professor of biology at the University of Washington, stated: "It's called the 'Sunshine Protection Act' because you get an extra hour of light at the end of the day. But you will take that hour from the morning."
Lead author Guadalupe Rodríguez Ferrante, a postdoctoral researcher in biology at the University of Washington, noted that morning sunlight helps synchronize circadian rhythms affecting sleep, mood, and appetite. Schools near western time zone boundaries and those with early start times would face the largest increases in dark commutes. Mississippi and Alabama schools, which typically begin before 8 a.m., would see dark commute trips rise from approximately 2 million to more than 20 million per state.