If DST changes cause accidents and harm health, let’s stop. But should we also go from 4 time zones to 2? Good problem to give to a commission or the National Academies.

If the claims that the twice-annual change from Standard to Daylight Saving causes bursts of auto and workplace accidents and sleep-related heath problems are true, it seems to me the argument for getting rid of the changes is strong. I’d appreciate expert reader opinions on the state of the evidence. (Jennifer Doleac at U.Va. warns it might be bad for crime.) Since I’m a “late” person, I’d rather go to permanent DST, but that’s not based on any analysis of which would be better socially. The more radical proposal – to adopt year-round time and also collapse the continental U.S. from four time zones to two, an hour apart – would greatly improve my life,  both by shifting sunlight later in my day and by shrinking the time gap with the East Coast, making phone calls easier to schedule and reducing jet lag from a burdensome three hours to a trivial single hour. But again, I haven’t seen anything that looks like a benefit-cost study. This seems to me the sort of question that ought to be handed to a commission, or alternatively to the National Academies, for a study and some recommendations. It’s important enough to be worth getting right, and ought to have roughly zero ideological loading. Update As noted in comments, the right way to deal with the problem of kids going to school in the dark is to start the school day later, which would also better fit the circadian rhythm of teenagers and reduce after-school crime and other mischief.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: Markarkleiman-at-gmail.com

20 thoughts on “Timekeeping”

  1. According to the link, energy savings from DST are negligible, but the study is for California and maybe things are better further north. Anyone know how much energy this was projected to save when it was adopted? I’m quite open to the thought that in energy/environmental terms the scheme is basically a feelgoodery, a ritual.

  2. I’m against daylight savings time because that extra hour of daylight accelerates fading of fabrics.

  3. maybe not ideological, but I recall a lot of complaints about “meddling with God’s Time” the last time DST was extended. The main objection to running DST all year is so kids wouldn’t be going to school in the dark, but of course school starting times are much too early for children’s diurnal rhythms anyway. Farmers hate being in the “wrong”time zone, like most of Indiana, and the semiannual switch back and forth, because their work schedules are mainly solar. There’s an interesting history of Indiana’s time wars here http://en.wikipedia.org/wiki/Time_in_Indiana .

    1. Pffff, here in Michigan there are lots of kids who go to the school in the dark whether it’s DST or not. It’s just part of being on the western edge of the time zone and pretty far north. I agree with your point about diurnal rhythms. I’d love to know which genius in my district decided high school should get the early shift (on the bus around 630-700). I suppose it’s a combination of wanting to allow plenty of daylight for athletic practices after the school day plus parents of elementary school kids insisting they need lots of time to get the little darlings ready to go.

      1. Yes, this. Try getting involved in school system improvements and you pretty quickly learn that the entire system revolves around, first and foremost, the football practice schedule, which drives the options for busses which drives (limits) the options for evidence based practices in start and stop times and in community involvement completely. The only hopeful thing about all this concussion research is the chance of driving football out of the public schools (and their insurance costs) and turning into a club sport, privately financed and insured.

  4. I was stunned when a Shanghainese friend of mine told me China is on one zone. Wikipedia says it is still true: http://en.wikipedia.org/wiki/Time_in_China

    Result is that civil servants on the Western Frontier have a work day which is all out of joint with all around them, and rest of the people do things at appropriate times but the clock says it’s all wrong. And things like railroad timetables are simpler. When I was a kid in Berkeley the dads who worked in stocks got up and to work terribly early and then got off in the early afternoon. Bad for family life on the breakfast, great for Little League.

    1. Unofficially in western China they keep using their own times. It is ‘official’ time which is fixed.

  5. Run everything on GMT everywhere. So what if that means getting up at 10am and staying up until the wee hours of the morning, at least everyone will agree on what time it is.

    1. I agree with this wholeheartedly, except it should be called UTC. Most computing systems do this already, and have done for decades. There’s entirely too much politics (and chauvinism) involved in time standards. Back in (I think) the early 1990s, Portugal, which had for ages been on the same time as London, switched for presumably political reasons to continental Europe time (i.e., one hour later than London), even though Lisbon is west not only of London but of Dublin. On top of that, they went on daylight time with continental Europe, with the result that during the summer it was broad daylight at 10:30 pm, and during the winter it was still pitch black at 8:30 am. After two or three years they reverted to London time, but it was ugly while it lasted.

  6. If the main concern is safety issues, then just two time zones will aggravate them. While humans like to run their affairs by clocks, the human body is run by a number of cues about time and its proper response. Get too far out of kilter and all kinds of fatigue and attention-span issues start cropping up. Just two time zones would place more people at risk of having body clocks incorrectly synchronized with the environmental cues around them.

    The time shifts have similar problems and happen twice a year. I’d agree that year-round common time would be better, whatever time that happens to be, rather than the forward and back nonsense. I worked nights for a number of years and these shift were particularly hard to follow if you’re already on shift work, another largely ignored danger of the workplace where the pittance paid as a night differential insufficient for the cost to health and family life.

    1. i find all of this deeply silly and it’s the kind of thing that only a technocrat or an executive could think was reasonable. sure, china uses one time zone but the only people who live their lives by it are the technocrats and the executives. most other people live their lives tied to a thing called the sun. alaska absolutely has only two time zones but their are only about 730000 people in the whole state. there are 50 cities in the rest of the united states with a larger population with that and because of alaska’s proximity to the arctic circle the tie to normal solar rhythms is less pronounced. i’m fairly amused that dr. kleiman thinks this idea is worth studying instead of laughing back to the executive suite.

  7. I think daylight savings time makes great sense in the right latitudes (far enough north for there to be significant seasonal variations in the amount of sunlight) – because people are not going to shift their work and living patterns gradually to accommodate the differences. Most people start work at 8 or 9, so having the sun come up at 5 a.m. is wasting daylight. The same people don’t go to bed when it gets dark, but would be happy (are happy, demonstrably) with the extra hour of daylight in the evening, when they are free to enjoy it.

    DST goes too late in the fall – much further from the summer solstice than in the other direction of the year. And people living at the far western end of the time zone get pretty dark mornings by October. It does matter where you live. It makes no sense to have a time zone much different from the 1/24 of the distance around the earth, because the sun time gets too far removed from clock time.

    I don’t think serious energy savings have ever been demonstrated, and I don’t believe the stories of accidents and so on as a consequence of the one-hour shift – and certainly not in the fall, when no one is deprived of sleep by the change. It’s a matter of convenience, and sufficiently popular that it is widely adopted around the world (in the right latitudes) and has become more thoroughly ingrained in society even in the past few decades. (In the 1950s and 60s, the Canadian National Railway kept its timetables on standard time all year round. Passengers and shippers just had to remember it was different. That changed.)

    1. Personally, I loath it; Just as the hours of daylight get short, the clock shifts, and I lose an hour of daylight I could actually USE in the evening, just so I can have light on my drive to work. Thank goodness my new boss is flexible, and will likely let me shift my schedule an hour to negate this idiocy.

      1. having grown up on a farm and working over the years with cattle and pigs, truck gardens, and orchards i have an affinity for standard time. even in my work as a teacher i prefer my light in the mornings. this, as with so many things, is all a matter of perspective.

    2. UK data suggests c. 100 lives saved pa — vs about 3,000 auto related deaths pa. We are mostly between 50 degrees and 56 degrees latitude.

      So there are empirical studies that it would save lives (staying on British summer time). See my other post below. Politically, the farmers especially in Scotland don’t want it, so it doesn’t happen.

      It would also be a major political issue if we were to be seen to align ourselves with the Continent on anything– I can see the UK Independence Party (our ‘tea party’) running amok with that one ‘keep time British’ etc.

      The reason being you would have an extra hour of darkness in the morning, but drivers are more alert in the morning. Conversely, that crucial time 3.30-4.30 would remain daylight- that’s when driver alertness falls, and kids are coming home from school. Hence the life savings.

  8. The French have a fete for short films on December 21st-shortest day of the year. http://cliffleeparis.wordpress.com/2011/12/21/the-shortest-day-of-the-year/

    Perhaps we should do the same?

    In Paris for much of the cold season the sun does not rise until 8:30am or later and it is dark before 5PM. I saw many school kids walking in the dark to get to school there in the Winter. French education seems to have survived. Indeed, I had a class at the Sorbonne that began at 7AM in the Winter. The class was over long before the sun came up.

  9. IIRC, one big rationale for adopting DST during WWI had to do with extending factory work farther into the evenings. That was back when we had lots of factories that relied on natural lighting and were concentrated in the Northeast and Great Lakes latitudes. Much farther north and you don’t really get usable morning or evening sunlight in winter, much farther south and it really doesn’t matter that much. Another had to do with reducing demand for coal, which was in short supply. Since neither of these is particularly critical now, the question seems to be primarily about whatever benefits there might be in that relatively narrow, if populous, swath across the country from shifting daylight around by moving clock noon away from solar noon.

    Displacing solar noon by an hour as is done for DST doesn’t fundamentally bother me and might be a useful fudge. We haven’t paid that much attention to solar noon anyway for as long as we’ve had time zones. But it bothers the hell out of me that we displace it and then re-emplace it so there are two changes a year. Personally, I find it takes me two weeks each time to get adjusted to it, and I know it costs me something in sleep time and disturbed sleep patterns and probably in mental efficiency, and it doesn’t matter which way the change goes. I don’t care what system gets adopted or what relation it has between clock noon and solar noon, just as long as it’s stable– it can be standard time or DST or we can split the difference; I really don’t care, just as long as we stop screwing with peoples’ body rhythms.

    I have to say I’m profoundly grateful we ultimately didn’t go for the prize lunacy of bumping up another hour for about two months in the middle of the summer, as was seriously proposed at one point. But we still went for the lesser idiocy of the extra six weeks or whatever of DST instead. What was the rationale for extending it that way? Feeling the effects of the time change as I am now, I can’t remember.

    Bring on the good studies of what the switch really does to people!

  10. This debate rages in the UK– going to British Summer Time all year round.

    This was done during WW2 to save electricity.

    The thing about kids *going* to school in the dark means that they *come home* in the day (remember, we are 50 degrees latitude and north– much further north than lower 48 USA or southern Canada).

    Studies show drivers are *more alert* in the mornings, and *less* alert around 4pm ie when kids come home. So it has been estimated that moving to BST would save children’s lives.

    (I don’t have a statistical fix on that number, but it is more than 10, and less than 100 lives pa, I believe– something over 3,000 people a year are killed on Britain’s roads).


    estimates 80 deaths pa (Royal Society for Prevention of Accidents)


    According to the Royal Society of Prevention of Accidents (RoSPA), road accident figures from 2011 showed pedestrian deaths rising sharply from 25 in September to 34 in October, 48 in November and up to 65 in December.

    A 1998 report from the Transport Research Laboratory suggests the system should be replaced with Single/Double Summer Time (SDST). Under this system of timekeeping, the sun would rise and set throughout the year one hour later by the clock than at present.

    The report estimates this would reduce the number of road deaths per year by between 104 and 138. [/quote]

  11. For real data, start with insurance records and experience. I’ve just heard that one of them warned drivers in the Bay Area that the accident rate goes up significantly for about two weeks after each time change.

    Another good neutral source would be hospital admissions for stress-related and accident-related conditions.

Comments are closed.