Ride-hailing giant Uber says it's using smartphone gyrometer data to double-check if drivers on its platform are speeding.

At least, it does for a portion of its drivers on a new pilot program. Joe Sullivan, Uber’s chief security officer, explained that the tactic is meant to corroborate whether a low "star rating" from a passenger may have stemmed from how fast their Uber driver was going.

“If the rating is low, we ask why,” Sullivan said. “We need to check what actually happened. Mostly it’s about talking to both sides. But increasingly technology can help get to the truth.”

Sullivan says the measure is part of a mix of methods to address road safety. In North Carolina, the company has provided Bop It toys in the backs of drivers’ cars to keep drunk passengers entertained, according to the company—though some have pointed out that the strategy of treating passengers like children could come off as insulting.

Some drivers in Seattle, meanwhile, are using color-coded lights to help riders find the right car at night. In the future Sullivan says Uber could use gyrometer data to verify whether drivers were constantly messing with their phones and offer them smartphone mounts.

There’s no doubt that safety is important. But to Uber’s critics, all that monitoring might seem to give Uber more control over its drivers than it ought to have, given the company's stance that its drivers are independent contractors, not employees. Some drivers have already alleged that anything below a 4.6 average rating can get them deactivated from the system. Now, it seems, Uber is looking to have even greater oversight.