The number of fatalities in auto accidents dropped markedly in the year after Utah lowered the legal blood-alcohol limit over which drivers would be considered impaired, according to new federal data released Friday.

A study conducted by the National Highway Traffic Safety Administration (NHTSA) found the number of fatal crashes in Utah dropped by almost 20 percent between 2018 and 2019 after the state lowered its legal blood-alcohol limit from 0.08 percent to 0.05 percent.

The number of fatalities dropped too, by more than 18 percent — even though Utahans drove more than they had the year before, and even though alcohol sales grew.

Nationally, the number of fatal crashes declined by 5.6 percent over the same period. States that neighbored Utah did not see the same decline in accidents or fatalities that the Beehive State did, an indication that the lower blood-alcohol limit was a factor in the drop-off.

“Utah typically has one of the lowest rates of impaired driving fatalities in the nation, but this study shows that all states have room for improvement,” NHTSA Deputy Administrator Steven Cliff said in a statement accompanying the new study.

Utah is the only state in the nation that has set its legal blood-alcohol level lower than the federal limit of 0.08 percent. The state, where more than two-thirds of residents identify as Mormon, is used to the vanguard position when it comes to tough alcohol laws: In 1983, it was the first to lower the legal limit from 0.10 percent to the 0.08 percent that the rest of the country later adopted.

The National Transportation Safety Board has been urging states to adopt the new lower 0.05 percent standard for nearly a decade.

“This study will be a useful tool for other states considering a move to 0.05 percent,” Cliff said.

The study suggested that the decision to lower the legal limit has had behavioral effects in Utah, too. The number of drivers involved in crashes who tested positive for alcohol dropped by 15 percent. In a survey conducted in conjunction with the study, 22 percent of those who said they drink alcohol said they had changed their behavior after the law took effect — most of whom said they found an alternative way to get home.