Monday, September 8, 2008

Sunlight and Time

A recent Slashdot story's discussion got way off track (you don't say!) and people started arguing about the merits of daylight saving time. As a cyclist and runner I'm often pretty consumed with not getting killed on the road. So...

Spring Forward:

Next we compare the total of traffic fatalities for the Monday immediately following the DST shift with the pooled frequency of accidents for the previous and following Mondays. The spring DST shift (where one hour of sleep is lost) shows the expected increase in accidents with relative risk (RR) of 1.17 [95% CI=1.07/1.29, p2(1)=10.83, p < 0.001]. This 17 percent increase is larger than that observed in previous studies. The same analysis conducted for the fall DST shift, however, produces an insignificant reduction in traffic deaths [RR=0.97, 95% CI=0.89/1.07, p2(1)=0.29, ns.].

And Fall Back:

However, recent research indicates that pedestrian fatalities from cars soar at 6:00 p.m. during the weeks after clocks are set back in the fall. Walkers are three times as likely to be hit and killed by cars right after the switch than in the month before DST ends. Researchers from Carnegie Mellon University, who found a 186 percent jump in the risk of being killed by a car for every mile walked, speculate that drivers go through an adjustment period when dusk arrives earlier. Although the risk drops in the morning, because there are fewer pedestrians at 6:00 a.m., the lives saved in the morning don’t offset those lost in the evening.

So overall traffic accidents increase after the spring switch because the cagers are asleep, and pedestrian fatalities increase after the fall switch because the gradual shortening of daylight is interrupted, plunging their commute suddenly into darkness. I think I'd rather we not do any of this switching. Since we're now on DST for almost two-thirds of the year, why not use it all the time?

The funny thing is that people in my generation seem to waste morning sunlight in bed and keep our lights on late into the night. I'm certainly guilty of it now, though that hasn't always been true. In middle school I practiced clarinet early in the morning, before before-school band rehearsals. One summer I wrote music before morning cross-country practice. In high school I woke up early one winter, prompted by Jason Zencka and a Thoreau quotation. I think most of those days I went running. Once I hit college, though, I never managed to get my ass out of bed in time to do much more than take a shower and shovel down breakfast (if that) before class. That has certainly held true since graduation.

When I moved to my current apartment in June I took the opportunity to shake up my routine a bit. I waste less time on the Internet than I did before, and have been able to read more books. I still waste too much time on the Internet, and most of it is late at night. I think I'm going to try to get to bed earlier, wake up earlier, and use the morning sunlight to run. And hopefully I can use this shake-up to really cut time-wastage. We'll see.

1 comment:

Danielle in Iowa said...

Ever since living in the DR I calibrate my day to sunrise. So in the summer I am often up early and in the winter I am up late. Of course, I can do this being a grad student... But I really like it this way - I can set an alarm, but really I wake up pretty naturally as daylight begins to break.