The article, “Here’s how a permanent daylight saving time would impact sunset and sunrise times in Baltimore” (March 16), summarized the earliest sunset and latest sunrise that Baltimore would experience under permanent daylight saving time (DST) and the impact of the change on winter holidays. It did a great job of whittling the potential change that the Sunshine Protection Act would bring to our city down to an easy take-away. Do the politicians voting on the Sunshine Protection Act have such a clear picture of the impact of the changes?
I’m an operational fatigue scientist based in Baltimore, and part of my job is to examine risk in relation to time of day using the biomathematical modeling software SAFTE-FAST. Our team used the software to model the one-hour change in sunrise and sunset during the autumn, winter, spring and summer in five U.S. cities in five different time zones (New York, Chicago, El Paso, Los Angeles, and Anchorage). We looked at light exposure across work and commute times for daytime work, high school and shift work schedules. Shift workers are generally left out of the conversation about DST, but constitute about 16% of the working population.
An argument in support of DST is that darkness contributes to the accident risk during evening commutes, so we looked at the commuting data that overlapped with morning and evening rush hours. Our analysis indicated that darkness during morning rush hours may constitute a greater risk due to fatigued shift workers being on the road with daytime workers and student commuters than darkness during evening rush hours when students are already home and shift workers are going to work.
We also graphed out the differences in daylight between three time change arrangements (permanent DST, permanent Standard Time, and the current system) across the five cities by season in relation to rush hours and work/school schedules to provide a picture of the actual change to anyone from any of the five U.S. time zones that use DST to see. A preprint of this scientific analysis can be found at https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4138534.
— Jaime K. Devine, Baltimore
The writer is an associate scientist for operational fatigue and performance at the Institute for Behavior Resources, Inc.
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