Daylight savings time

This weekend much of Australia’s Eastern seaboard will switch to daylight savings time (DST). Being in Western Australia where it is not practiced (it was defeated in a compulsory 2009 referendum), the only annoyance is making sure I’m adding 3 hours instead of the usual 2 to the time difference.

Nevertheless, I am subjected to the debate whenever I browse my favourite news sites, turn on the TV or listen to the radio. The usual arguments cited are energy conservation, more time outdoors, reduced traffic accidents during rush hour, and even crime prevention. These are understandably hard to quantify, with a quick search revealing a U.S. Department of Transportation (1975, 1% saving) and a separate U.S. Department of Energy study (2008, 0.03%) showing small reductions in energy consumption. However, the findings have been disputed, e.g. Matthew Kotchen and Laura Grant found in 2011 that DST actually increased energy consumption by 1%.

Then there are the rent seekers who tend to come out of the woodwork whenever policy that might benefit them is proposed, e.g. the golf industry, which has lobbied for DST in the past. In 1986 it estimated DST was worth up to US$400 million annually in extra sales and fees (that’s nearly US$1 billion in today’s dollars).

In terms of costs, from what I can gather the most quantifiable cost comes from an increase in fatalities, especially on roads, following the switch to/from daylight savings:

The sleep deprivation on the Monday following shift to DST in the spring results in a small increase in fatal accidents. The behavioral adaptation anticipating the longer day on Sunday of the shift from DST in the fall leads to an increased number of accidents suggesting an increase in late night (early Sunday morning) driving when traffic related fatalities are high possibly related to alcohol consumption and driving while sleepy.”

Others have argued that our circadian body clocks never adjust to daylight saving time, causing minor jet lag with all of the associated costs.

Ultimately, the costs and benefits are relatively small and difficult to quantify. In such a situation I tend to err towards the principle of primum non nocere, or first do no harm, and advise against DST.


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