
Effects of Daylight Saving Time on Traffic Accident Risk - bookofjoe
https://www.cell.com/current-biology/fulltext/S0960-9822(19)31678-1
======
benrbray
I recognize that my position is uncommon, but I am in favor of what I call
"2-DST" (two minus DST), a position which recognizes that DST is fundamentally
_backwards_. Fewer daylight hours in the winter means we should turn the
clocks forward in the _winter_ , not the summer!

"2-DST" is permanent daylight savings, except we additionally set the clocks
an hour forward for the winter (just like we do now, in March).

More opportunity for sunlight. More outdoor activity in the evenings. Less
electricity. Less crime. Better for most businesses and most people.

~~~
scrollaway
I always find these arguments kind of weird. Whether we turn or stop turning
the clocks forwards/backwards doesn't mean we have to keep business hours the
exact same, or even keep them static.

Must be a US thing, what with all its timezones. China has a single timezone,
and doesn't observe DST. Do you think that means people in the extreme west of
china _have_ to wake up at the exact same time as people in Beijing?

In fact, according to Wikipedia
([https://en.wikipedia.org/wiki/Xinjiang_Time](https://en.wikipedia.org/wiki/Xinjiang_Time)),
the Xinjiang region of China has two timezones used concurrently. I guess
people just wake up twice: Once at 7am, and again at 7am two hours later :)

Anyway my point is, you could have the US go on a single timezone and stop
observing DST. Ok, well, you don't have to open your business at 8am across
the country… if your new TZ is based on Austin TX, you just open at 8am in
Austin, 7am in NYC and 10am in LA.

Want to give your employees more daylight in winter? Shift business hours by
an hour.

~~~
gpvos
_> I always find these arguments kind of weird. Whether we turn or stop
turning the clocks forwards/backwards doesn't mean we have to keep business
hours the exact same, or even keep them static._

The entire reason we have summer/winter time is that changing the time is
easier than changing business hours.

~~~
dooom
Why would changing business hours be so complicated?

~~~
gpvos
There are thousands of businesses involved. Also, work contracts.

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Mountain_Skies
Georgia is putting DST on the ballot this November. Voters will have a choice
to stay with DST, going to standard time year around, or asking Congress for
permission to stay on DST year around. My guess is none of the options will
receive a majority vote but year around DST will get the plurality. Since that
requires Congressional approval and the ballot referendum is non-binding,
nothing will change as a result. Having discussed the issue over the years,
it's also a bit sad realizing how people don't understand that this doesn't
actually create an extra hour of sunlight, it just shifts an hour of pre-noon
sunlight to be afternoon sunlight. A surprisingly large number of people are
quite insistent that it creates more sunlight per day, citing longer daylight
hours during the summer months as proof.

~~~
mjevans
Vote for no more adjustments, I don't care if that's UTC, nation wide
'Eastern', DST or not DST... just leave things the same all year. I've got a
slight preference for everyone going UTC with no DST so that meetings and
events are easier to schedule across the world.

UTC would be great if it weren't for how everyone wants to think of E.G. 8AM
or 9AM or whatever as a common start time and then uses DST to try and adjust
the clocks rather than the times people do things.

The current time isn't particularly useful either, noon isn't even directly
tied to the solar apex in most places (due to the timezones and more complex
orbit / tilt interactions).

~~~
ska
> UTC would be great if it weren't for how everyone wants to think of E.G. 8AM
> or 9AM or whatever as a common start time

You mean people want to think about hours in a way that is useful to them
where they live? Doesn't sound crazy.

If everyone moved to UTC you wouldn't solve any real problems. Sure, everyone
in New York could get used to their day starting at noon or whatever (to what
benefit?) but if you wanted to schedule a meeting with someone in spain (or
california) you would still have to figure out the time change to make it a
reasonable time for you both.

Any way you slice it, you're just pushing the problem around to different
places.

~~~
scrollaway
Your day "starting" at 00:00 sounds a lot easier to reason about than the day
starting at 08:00.

We did get used to the day starting at a weird time for no particular reason,
and whenever you change jobs you'll get used to a slightly different time
anyway.

I don't see how it's more useful the way it is now than any other way. This is
like trying to justify that moving summer holidays by one day would disrupt
everyone's way of thinking.

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throw0101a
To anyone advocating all-year DST: you're wrong.

The chronobiologists say permanent Standard Time is the best thing for humans:

* [https://www.frontiersin.org/articles/10.3389/fphys.2019.0094...](https://www.frontiersin.org/articles/10.3389/fphys.2019.00944/full)

* [https://www.theglobeandmail.com/opinion/article-turn-back-th...](https://www.theglobeandmail.com/opinion/article-turn-back-the-clock-on-daylight-savings-why-standard-time-all-year/)

* [https://en.wikipedia.org/wiki/Chronobiology](https://en.wikipedia.org/wiki/Chronobiology)

Edit: down vote all you want, that won't change the peer-reviewed published
papers.

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throwaway8451
DST is a very sensitive topic, so better use a throwaway ;) Here are examples
what would happen if DST were abolished:

If DST ('+1') is adopted permanently, the main effects will be during winter
in that sunrise is now an hour later (bad) and sunset as well (which is ok).
An example for Berlin, in December: if sunrise used to be at 8:00 (8 a.m.)
normal time it is now an hour later at 9:00 (a.m.) (spend some time further
north and you will know how much this would suck). Sunset that used to be
around 16:15 (4:15 p.m.) is now at 17:15 o'clock (5:15 p.m.) (good/ok).

If normal time ('+0') is adopted, the interesting effects are during summer:
sunrise is now an hour earlier than it used to be with DST and the same of
course with sunset.

Example for Berlin, in July again: sunrise that used to be at 5:00 o'clock
(a.m.) in DST is now at 4:00 (a.m.) (bad), sunset that used to be at 21:30
o'clock (9:30 p.m.) is now at 20:30 o'clock (8:30 p.m.) (bad if you like
spending long summer evenings outside).

From my experience most people do not actually hate either, they just do not
like the _sudden transition_. Shifting the daily routing to later hours,
especially the sleeping time, is not that bad in autumn. Changing it forward
in the spring is harder but not really a problem if you _gradually change your
sleeping and meal times in advance_. I'm currently at it by going to bed a bit
earlier, getting up earlier and (trying to) change eating times. Lunch is a
bit problematic but breakfast and dinner do not affect others so much, so it's
easier to shift them.

~~~
ygggvg
It really affects me every year. My grades went down after the switch.

As long as we are not just able to gradually transition I prefer to get rid of
it and I'm quite happy that it's going to happen.

Nonetheless if sun goes down at 4 instead of 5 I wouldn't feel any issue with
it. Winter is dark I leave in dark and go home at dark.

~~~
throwaway8451
What makes a gradual transition on your own impossible for you if I may ask?

~~~
ygggvg
My work schedule on one side and the additional effort on the other
(coordinating with my wife, changing alarm regularly, matching that with
public transport.

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gyrgtyn
I, for one, would like to wake up when the sun is up, and go to sleep when the
sun is down. Isn't this this the same website where everyone is familiar with
Why We Sleep? Standard Time forever

~~~
James_Henry
Standard time isn't perfect though. The more west someone is in a time zone,
the less sleep they often get because the sun goes down later in the evening.
Some have estimated it to be as much as 20 minutes of sleep less, which is
very significant over time.

What we really need is for schools and work to start later in the day for a
larger number of people so that the morning can be a time to sleep in, or if
you are a morning person do your morning things.

I almost think that getting rid of time zones in the US might make it so that
people are more cognizant of where the sun is and so that society runs on a
more local time.

~~~
gyrgtyn
> The more west someone is in a time zone, the less sleep they often get
> because the sun goes down later in the evening.

isn't this even worst in DST? Maybe I'm thinking about it backwards...

~~~
James_Henry
Yes, this is worse during DST.

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vagab0nd
Genuine question to the experts: What are the chances that this effect is
caused by how we attribute the accidents to time intervals? I haven't read the
whole paper, but when they say accident rate is increased by 6%, is that
counted by 24-hour intervals? Or by calendar days?

~~~
radicsge
It is also a question what happens in Autumn if it balances out then there is
no news actually.

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jagged-chisel
I don’t particularly care around what time range we center the day, I just
want to stop changing twice a year. Pick one and stick to it.

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luxuryballs
Now that we have so much digital we should experiment with a gradual shifting
clock that spreads the time change out over the entire year. Clock that
follows the tilt of the Earth. It sounds crazy and traditional clocks and
watches and cars would all suffer but someone will come up with something like
this, even if just conceptual, and it will be cool. Just wait!

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ck2
It's funny how the majority of people can't get politicians to undo DST for
decades now. Makes the tiny change in healthcare for some look like a major
miracle.

I think they just altered the DST start/end days, I remember it used to end
before Halloween until too many kids got hit or killed by cars in the dark.

~~~
Mountain_Skies
In the US the dates of DST were changed during the Bush administration as a
cheap political gimmick to make it look like he was doing something about
energy prices. It didn't help much in that regard but caused plenty of chaos
in the IT sector where a significant amount of systems were designed to adjust
twice a year for DST but weren't designed for the date span of DST to change.

~~~
James_Henry
From what I understand there are still a lot of hospitals that have to switch
to paper twice a year because of DST issues. If I remember right it is mainly
Epic.

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sunbear-lover
Now that we have so many digital devices with GPS, why not go with continuous
time zones? In the sense that if I move a certain distance to the east the
time will change by a certain number of minutes, rather than chunking
everything into hours. Seems much more accurate and useful.

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Grimm665
And so the semiannual discourse about DST begins, only to be forgotten a week
after the clocks are changed. See you all again in November where we discuss,
and again fail to implement any change in policy.

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northernjames
Accident risk has been shown to decrease by the same amount when the time
switches in the fall. It's a wash.

~~~
J-dawg
I thought that as well, but this study appears not to have found that

> and there were no effects of the fall-back transition to Standard Time (ST)
> on MVA risk

EDIT: It seems our assumption was correct, at least for the UK:

> There is substantial evidence that fewer people would be killed and
> seriously injured on Great Britain’s roads if this country were to put the
> clocks forward by one hour throughout the year. The Department should take
> the lead in re- examining the practice of changing clocks at the end of
> British Summer Time with other central Government departments.

I wonder why the OP study (using US data) found something different?

Source:
[https://publications.parliament.uk/pa/cm200809/cmselect/cmpu...](https://publications.parliament.uk/pa/cm200809/cmselect/cmpubacc/665/665.pdf)

~~~
Izkata
First thought without even trying to compare the DST shift directly to guess a
reason: Comparing sunrise and sunset across the year, London to Chicago,
London is slightly more extreme across the year.

London:
[https://www.timeanddate.com/sun/uk/london](https://www.timeanddate.com/sun/uk/london)

Chicago:
[https://www.timeanddate.com/sun/usa/chicago](https://www.timeanddate.com/sun/usa/chicago)

Assuming my co-workers are typical, workday also seems to end more like 5:30pm
in London vs 5pm in the US.

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CamperBob2
Very hard to believe that more daylight later in the day is a net negative for
traffic safety.

In any case, the solution is to pick one timeframe and _stop changing it_.

~~~
java-man
It's not the amount of light, it's the abrupt change in the sleep pattern.

~~~
izzydata
Never changing it would only result in gradual changes of sleep pattern.

~~~
munk-a
And humans tend to do alright with gradual changes - they tend to have
problems with sudden changes (like flying to a different time zone)

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minikites
I'm a fan of changing the clocks twice a year for the reasons nicely laid out
in this article: [http://www.leancrew.com/all-this/2013/03/why-i-like-
dst/](http://www.leancrew.com/all-this/2013/03/why-i-like-dst/)

>If we stayed on Standard Time throughout the year, sunrise here in the
Chicago area would be between 4:15 and 4:30 am from the middle of May through
the middle of July. And if you check the times for civil twilight, which is
when it’s bright enough to see without artificial light, you’ll find that that
starts half an hour earlier. This is insane and a complete waste of sunlight.

>If, by the way, you think the solution is to stay on DST throughout the year,
I can only tell you that we tried that back in the 70s and it didn’t turn out
well. Sunrise here in Chicago was after 8:00 am, which put school children out
on the street at bus stops before dawn in the dead of winter. It was the same
on the East Coast. Nobody liked that.

Changing clocks is a hassle but the alternatives are worse.

~~~
phaedryx
It would be better for children to start school later in the day anyway.

~~~
rypskar
Don't DST in practice make school start an hour later parts of the year? Where
I live it don't get dark for 2-3 months during the summer and it was never
easy to get up in the mornings. The same at the middle of winter there is no
sunrise so not possible for schools to start after dawn.

I think I did read some place that it was more connected to that our sleep
pattern isn't accurate with 24h, so if we get up later we would go to be later
and be back to square one.

~~~
nulbyte
> Don't DST in practice make school start an hour later parts of the year?

It's about half and half, when you consider the school year starts in daylight
saving time, switches to standard, and then switches back. I don't see how
changing the time kids go to school twice in the year is beneficial. And I
certainly don't see how sleep-deprived bus drivers in the spring are an
acceptable risk.

