Why Covid has seen fewer Fender-Benders but more road deaths


In the United States, what happened in Virginia also happened in many other states. Why? Perhaps it was pandemic rage, a direct consequence of the psychological burden of the pandemic? Or have the anti-Covid measures taken the more cautious part of the population off the roads, leaving a riskier group of drivers remaining, with a predictable outcome? Or maybe it had nothing to do with Covid – maybe it was a continuation of a pre-existing trend. After all, the number of road deaths has been increasing in the United States for a decade, partly because of larger vehicles and partly because more and more drivers are drinking, using drugs or looking at their phones.

All of these factors probably played some role, but another simpler factor may be even more important. A meta-analysis of dozens of pandemic crash studies around the world finds, in general, a pronounced reduction in both traffic and road deaths during the pandemic in most countries. Yet this reduction has been accompanied by an increase in the proportion of fatal accidents linked to factors such as speeding. The most frequently cited cause: less congested roads, which allow for faster driving – what traffic experts call “the speed effect”.

Perhaps pandemic psychology also played some role. But the quite ordinary psychology related to the lure of open roads seems to have had a significant effect.

Research published in the World Journal of Emergency Surgery reviewed more than 100 studies on road crashes and their consequences during the pandemic. Summarizing the findings of such a large study is not easy, but one of the main themes is that traffic patterns differ significantly from country to country. For example, traffic densities have dropped by 25% to 75% in various European countries, compared to an average of 40% in the United States. the total number of road deaths increased slightly.

But there were commonalities. Most strikingly, in all nations the Covid period has shown a significant shift towards more severe and deadly crashes involving high speeds. In Spain, the fraction of fatal accidents quintupled in the first year of Covid. Similarly, crashes involving extreme speeds have become three times more likely in the UK. In the United States, the number increased by 65% ​​in Boston and 167% in New York. They almost quadrupled in Chicago.

Numerous studies have also suggested a fairly simple cause for this result: less traffic congestion. For example, a detailed study in California based on extensive accident, speed and traffic data found that freeway travel and the number of collisions decreased significantly during the pandemic, but the frequency of serious collisions increased. due to reduced traffic congestion and increased driving speeds. . The study’s lead author, University of Colorado traffic policy economist Jonathan Hughes, attributes the increase to the “speed effect,” a well-known traffic phenomenon.

“The ‘speed effect’ is the increase in road fatalities due to higher average traffic speeds,” he explained to me over email. “On many California highways, speed is generally limited by congestion, not speed limits or driver preferences. With many drivers staying at home at the start of the Covid-19 period, the decrease in traffic allowed the remaining drivers to drive faster, which meant that the accidents that occurred were more serious as they occurred. at higher speeds.

Significantly, Hughes and his colleagues found that the increase in fatalities from extreme speeds was most pronounced in California counties with higher levels of congestion before the pandemic, suggesting that is where reducing congestion allows drivers to increase their speed the most.

Nonetheless, Hughes suggests there is some sense to the idea that the pandemic could have changed the behavior of the riskiest drivers on the road, although he says the story is more complex than most people. don’t think so. If traffic is stop and go, the danger posed by a risky driver is mitigated by the congestion of other cars on the road. Reduce traffic congestion and risky drivers are no longer constrained and can potentially drive more dangerously. Thus, the speed effect could involve a combination of reducing traffic jams allowing everyone to drive faster, while removing some constraints for riskier drivers.

“We find evidence,” he says, “of increases in the proportion of crashes involving drivers generally considered to be riskier. The proportion of crashes involving male drivers rose from 61% in the months before Covid to around 67% during the initial period of Covid. However, the main effect on fatalities appears to come from higher average speeds for all drivers.

One of the paradoxes of this “speed effect” is that it has implications that go beyond the pandemic. If the transition to deadlier crashes were less about the pandemic than about reducing traffic congestion, the same result would be expected from all traffic measures that reduce congestion, including the construction of new roads. Any policy that reduces congestion can increase speeds and also the severity of accidents. So if you’re frustrated with sitting in rush hour traffic again, consider the upside: at least no one is driving too fast.

More from Bloomberg Opinion:

• What else could Covid inflict on us? Ask the Aussie Bunnies: Faye Flam

• What if we continued to wear masks on trains and subways forever? : Justin Fox

• Making Sun Belt Cities More Like New York and Los Angeles: Conor Sen

This column does not necessarily reflect the opinion of the Editorial Board or of Bloomberg LP and its owners.

Mark Buchanan, physicist and science writer, is the author of the book “Forecast: What Physics, Meteorology and the Natural Sciences Can Teach Us About Economics”.


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