Amazon drivers will be subject to constant monitoring by cameras installed onboard Amazon delivery vehicles, The Information revealed on Wednesday. An Amazon-made informational video details how the system, designed by startup Netradyne, will work.

The driver-monitoring system is installed on the roof just behind the windshield, and it has four cameras. Three are pointed outside the vehicle, and the fourth is pointed at the driver. With the help of computer-vision software, the system will be able to detect potentially dangerous situations both inside and outside the vehicle.

For example, if a driver runs a stop sign, the system will detect it, issue an audio warning to the driver, and upload footage to Amazon’s services. Drivers will also be alerted (and footage will be uploaded) if they go too fast or follow other vehicles too closely. The system can also detect if drivers are looking at their smartphones or falling asleep at the wheel.

In other cases—including hard braking, sharp turns, and U-turns—the system will upload footage without alerting the driver.

In its video, Amazon emphasizes that the system doesn’t record audio and doesn’t have the capability for real-time monitoring. Amazon says that supervisors are never going to be remotely watching drivers as they travel along their routes. Drivers can disable the driver-facing camera when the vehicle is stopped.

Amazon argues that the cameras can sometimes be helpful to drivers. For example, if another vehicle crashes into the Amazon vehicle, footage captured by the cameras could prove that the Amazon driver wasn’t at fault.

Amazon argues that the system will improve on-road safety. Bad drivers will get feedback—either directly from the monitoring system or from a supervisor after the fact—and will hopefully improve their driving behavior.

Safety advocates have long called for better driver monitoring systems in all types of vehicles, but worries of a consumer backlash have slowed adoption in personal vehicles. A few carmakers—including Cadillac as part of its Super Cruise driver assistance technology—have added basic driver-monitoring capabilities to their cars.

Employers like Amazon are in a stronger position to insist that their drivers adopt technology like this that could improve safety and perhaps reduce Amazon’s legal costs in the process. Netradyne is just one of several companies selling technology like this for use in commercial vehicle fleets.

Back in 2017, I visited the headquarters of Nauto, a startup that sells a similar system. Last year, we wrote about Eyesight Technologies, an Israeli company that has developed a commercial driver-monitoring system that works even when drivers wear face masks.