Ride-sharing giant Uber has claimed that its service doesn’t just offer convenience, but safety for communities by reducing drunk driving rates. But a new study contradicts those claims.

Research published in the American Journal of Epidemiology compares drunk driving fatalities and traffic deaths on weekends and holidays in U.S. counties before and after the introduction of services like Uber, competitor Lyft, and others. The study centers on the 100 most populated American metropolitan regions and was conducted by scientists from the University of Southern California and Oxford University.

The results were striking. “We found that the deployment of Uber services in a given metropolitan county had no association with the number of subsequent traffic fatalities, whether measured in aggregate or specific to drunk-driving fatalities or fatalities during weekends and holidays,” wrote the researchers. Study co-author David Kirk told the Washington Post the report indicates “there’s still tons of room for improvement when it comes to reducing drunk driving fatalities,” of which there are 10,000 every year in the U.S.

There are several possible explanations for the findings. For one, customers who wanted to avoid drinking and driving may have simply switched over from using taxi services to using Uber and Lyft. It’s also possible that there still isn’t a robust enough supply of Uber drivers to counteract drunk driving, or that some people are simply willing to take the risk no matter what ride options are available to them.

In 2015 Uber commissioned a study in partnership with the advocacy group Mothers Against Drunk Driving (MADD) finding that DUI arrests and accidents fell significantly in areas where ride-sharing is available.

“In California, Uber’s home state and largest market, drunk-driving crashes fell by 60 per month among drivers under 30 in the markets where Uber operates following the launch of uberX,” the study authors stated. “That’s an estimated total of 1,800 crashes prevented since July 2012.”

Uber told the Post that “80% of riders says that Uber has helped them personally avoid drinking and driving.” In a statement emailed to Fortune, a company spokesperson pointed out that the new study “related only to DUI fatalities – not incidents,” and that the county-level data may actually be glossing over major metropolitan regions such as San Francisco and downtown DC.