Over a billion more dark-morning school commutes for K-12 children under the Sunshine Protection Act

The US House's approval of the Sunshine Protection Act has revived the debate between permanent daylight saving time (DST) and standard time (ST). Permanent DST would push school start times before sunrise in many regions. Health, sleep, and scientific organizations favor permanent ST because it keeps solar, biological, and social time better aligned,¹ which matters most for children and adolescents, whose rigid school schedules already conflict with their biological night and are linked to poor sleep and reduced cognitive and academic performance.^2,3,4 The safety consequences of the proposed change remain unquantified, but for children, morning light availability matters most, since most return home in daylight regardless of clock policy. Using real school start times for 14 states that have approved permanent DST⁵ and local sunrise times, we counted pre-sunrise commutes to school under each clock regime. Across the 14 states analyzed, permanent DST would require pre-sunrise departures for most of the winter, adding approximately 356 million days of pre-sunrise travel events among school-aged children (child days) relative to the current system (seasonally alternating between ST and DST). Applying the same approach nationwide, permanent DST would add more than 2 billion dark-morning commutes yearly. Analyzing a decade of national fatal crash records, we found higher odds of pedestrian involvement in dark-morning crashes than light-morning ones (odds ratio [OR] 1.77) and among pedestrians aged 5-18 (OR 2.22). Permanent DST would expose many more children to elevated pedestrian-crash risk, evidence that is relevant to the US' choice of a time standard.