Lowering blood alcohol concentration DUI laws from .08 to .05 would save lives, Colorado State research finds

A Colorado State University researcher says a study examining Utah's decision to lower its legal blood alcohol concentration limit for drivers found the change was associated with a significant reduction in fatal crashes.

Utah became the only state in the country to lower its legal blood alcohol concentration limit from 0.08 to 0.05 when the law took effect at the start of 2019. Because Utah neighbors Colorado, researchers at CSU used the state as a case study to examine the impact of the change compared to neighboring states with .08 limits. 

"The evidence is pretty solid," said Kaigang Li, associate professor at CSU's School of Health and Human Sciences.

"A BAC limit from .08 to .05 can improve roadway safety as well as save lives on the road," Li said.

The research found a significant reduction in crash fatalities in Utah after the lower legal limit was implemented.

While the researchers were unable to determine exactly what caused the decline in roadway deaths, Li believes the lower legal limit may have prompted drivers to think more carefully before drinking and driving.

"People will think about it. 'OK, if I need to drive, should I drink alcohol? Should I drink as much as I used to?'" Li said. "And also think about the legal side, and if I pull over by the police, if my BAC is greater than .05, I may (be going) to jail."

"We did see the reduction, significant reduction in Utah compared to neighboring states," Li said.

Li said the findings also align with research from other countries.

"We also see international data from several other countries, and with lower BAC, they also have solid evidence to the reduction," he said.

Asked whether Colorado should consider lowering its legal blood alcohol concentration limit to 0.05, Li said the decision ultimately belongs to state lawmakers.

"We should consider a .05 BAC limit. However, that decision will be made by lawmakers," Li said.

"As a person, as a driver on the roadway, I really want the road to become safer," he said.

Despite the research showing a lower legal blood alcohol concentration limit could reduce traffic fatalities, Colorado State University says previous studies suggest adopting such a policy could face significant obstacles, including political resistance, public misunderstanding and changing cultural norms surrounding alcohol consumption.