Can clock shifts increase the number of car crashes?

In the early hours of Sunday, October 27, we returned to standard time in the EU, until the end of March, when we will go back to summer time. This time shift will not be the last one in the EU, even though the European Parliament advocates for establishing a single time year round. This, if it happens, will not be a reality before 2021. There is a big worldwide discussion regarding its pros and cons, but… Does this affect driving and car crashes? Data seems to support this theory.

During World War I, daylight savings time was introduced to the United States as a measure to save energy, and it became a national standard in the 60s. Later, with the 1973 oil crisis, most developed countries adopted this time shift, taking place on the last weekend of October and March.

Though this measure was considered a way of saving energy, in the past few years there is an ongoing debate worldwide regarding its effectivity and necessity. If we look for arguments against it, we might have found another one: the increase in the number or car crashes linked to this matter.

In 1999, researchers from US universities Johns Hopkins and Stanford analyzed 21 years of data related to fatal car accidents collected by the US National Highway Transportation Safety Administration (NHTSA). This analysis revealed a small, but significative increase, in the number of deaths on the road the Monday after advancing the clocks in the spring. This way, the number of accidents with victims increased an average of 83,5 on that Monday when compared to an average of 78,2 on a regular Monday.

Likewise, a previous study carried out in Canada found out that the spring time shift caused an average increase of 8% in car crashes (without victims).

In fact, another report in the United Kingdom reveals that retarding the clocks in the fall causes a 14% increase in the number of accidents. And the lack of daylight seems to have a particularly important impact with a 36% increase in crashes between 5 and 8pm.

This risk varies around the country. Northern England records one of the highest growths in accident rates between October and November, with an increase of 48% at night and 8% during morning rush hour. Meanwhile, Scotland and eastern England also see an important rise in accidents rate during commutes, with an increase of 51% and 48% in crashes, respectively.

Londoners are the least affected by the time shift in their morning and evening commutes compared to other regions in the United Kingdom, with an increase of 22% in the number of accidents. Meanwhile, Wales, on the contrary, records a 45% decrease in the number of accidents during morning rush hour.

Another recent study by the Royal Automobile Club of Spain (Race) states that last Tuesday, October 29, between 8 and 9 am, was the most dangerous moment of the year to commute, since statistics indicate that it is the most likely period to have a car crash.

The reason for this is that when fall comes (the season with most accidents) and time shifts, people have a hard time adjusting to a new routine. In addition, statistics show that Tuesdays, between 8 and 9am is when most accidents happen.

This report also includes the highest-risk profile. This way, the highest risk of suffering an accident is for women between 16 and 29 years old driving to and from the workplace, and account for 70% of the total—, and men between 16 and 20 years old in accidents that happen during the working day. In addition, there are more crashes on the way to work (64%) than when returning home from the workplace.