Uber is requiring drivers to take a six-hour break after 12 hours of accumulated service, a nationwide mandate that will roll out over the next two weeks. The company plans to use location tracking to determine the amount of time drivers have been working, and will disable the app after they hit their limit. Uber is framing the update as part of a safety effort to prevent drivers from dozing off on the job, pointing to a National Sleep Foundation study finding that 7 million people admitted to falling asleep at the wheel within a two-week period.

Uber’s explanation of the changes claims that around 60 percent of Uber drivers in the U.S. work less than 10 hours a week, so presumably only a small percentage of drivers is working more than a half-day straight. The release also quotes Jonathan Adkins, executive director of the Governors Highway Safety Association, as saying, “This new feature has tremendous potential to protect not only Uber driver-partners, but also their passengers and, ultimately, all road users.”

Uber already had similar rules in place for drivers in cities like New York, where it instituted the policy in 2016 after reports of people working 16-hour days and protests over rate reductions, which were allegedly pushing drivers to work those long hours in order to earn a living. Now the limit is stricter and nationwide.

Uber’s new regulations add up the cumulative the hours a driver has been working since the last six-hour break. For example, the app will stop drivers after working two six-hour shifts if they did not take a six-hour break in between. A power-nap won’t cut it anymore.

Lyft has a similar policy that compels drivers to take six-hour breaks after 14 hours of driving. Business Insider posits that, because many rideshare drivers work with both Uber and Lyft, it may be possible to get around these limits by switching between the two. Nevertheless, the new rules should at least help to address the issue of driver fatigue—even if it doesn’t deal with the underlying pay issues that incentivized drivers to work those insane shifts in the first place.