Objective:

To estimate how permanent daylight-saving time (DST) would affect children’s pre-sunrise school commutes and examine the association between morning darkness and pedestrian involvement in fatal crashes.

Approach:

• School commute modeling: Researchers used school start times, enrollment, location, sunrise times, and an assumed 20-minute commute for 16,093 public schools serving about 8.6 million children in 14 states. They compared permanent DST, permanent standard time (ST), and the current sea…
• Crash analysis: Fatal crashes recorded in the Fatality Analysis Reporting System from 2015 to 2024 were analyzed for school-year weekday mornings from 7:00 to 8:30 AM, including associations between pre-sunrise conditions and pedestrian involvement.

Key Findings:

• In the 14-state analysis, estimated annual pre-sunrise school-commute exposure was about 554 million child-days under permanent DST, 198 million under the current system, and 97 million under permanent ST.
• A nationwide projection estimated that permanent DST would add about 2.14 billion pre-sunrise commutes annually versus the current system, assuming an 8:00 AM departure. Estimates were 2.63 billion with a 7:45 AM departure and 1.39 billion with an 8:15 AM depa…
• Among 10,305 fatal crashes on school-year weekday mornings, 1,754 involved pedestrians. After adjustment for clock hour and weather, pre-sunrise crashes had 1.77 times the odds of involving a pedestrian compared with post-sunrise crashes.
• For pedestrians aged 5 to 18 years, pre-sunrise crashes had 2.22 times the adjusted odds of involving a pedestrian; this subgroup analysis included 141 pedestrian-involved fatal crashes.

Interpretation:

The authors concluded that permanent DST would increase children’s exposure to dark-morning commutes and wrote that it would negatively affect youth sleep, health, performance, and safety.

Limitations:

• Commute estimates relied on assumed departure times rather than individual travel patterns; the nationwide projection used a fixed departure time because national school-specific schedules were unavailable.
• The crash analysis included fatal crashes only and did not capture nonfatal pedestrian incidents.
• The modeling and observational analyses cannot establish that permanent DST would directly increase pedestrian injuries or fatalities.

Conclusion:

The study found that permanent DST was projected to increase pre-sunrise school commutes, while fatal crashes before sunrise were more likely to involve pedestrians.

Sources:

• Current Biology (article context)