Research from Rensselaer Polytechnic Institute shows that traffic accidents decreased by nearly half during the two-month period at the start of the COVID-19 pandemic when residents of most states were under a stay-at-home order.

Using a detailed data set from the Louisiana Department of Transportation and Development, Jason Huh, an assistant professor in the Department of Economics at Rensselaer, found that traffic accidents in Louisiana decreased by 47% during March and May 2020 when Louisiana Governor John Bel Edwards issued a series of orders that closed businesses and schools, limiting mobility throughout the state. Accidents involving injuries decreased by 46% and those where an ambulance was called fell by 41%.

The number of fatal accidents, however, showed no significant decrease.

Dr. Huh’s research also showed that the decline in accidents was not equal across all demographics. Traffic accidents involving males, nonwhite drivers, and individuals in the 25—64 age group all saw a smaller reduction in accidents.

“The number of cars on the roads was altered substantially due to these stay-at-home orders,” Dr. Huh said. “Differential effects on individual behaviors might stem from differences in compliance with the lockdown or job characteristics such as whether remote work is possible.”

Dr. Huh was able to calculate the dollar value of the reduction in car accidents by combining publicly available data from the National Highway Traffic Safety Administration with his findings of a 47% reduction to approximate that the COVID-19 lockdown led to a decrease in car crash costs of $21 billion nationally during the March to May 2020 time period.

“While it may seem obvious that when fewer people are driving due to a public health crisis there would be fewer accidents, the precise magnitude of the impact and who it is impacting most is important and useful information for the public, researchers, and policymakers alike,” he said.

The research was published in Contemporary Economic Policy.