A new app is available to keep people nodding off while driving, if they’re wearing Google’s Glasses while it happens.

New software for Google’s Glass headmounted computer system was recently made available, called DriveSafe, as a way to keep drivers alert and direct them to a place to rest if they get sleepy.

In characteristic Google fashion, the software can be enabled by saying, “OK Glass, keep me awake.” From then on, the software makes use of two sensors in Glass to deliver visual and auditory notifications, if it senses that the driver is beginning to fall asleep.

The software uses an infrared light sensor and a tilt/angle sensor in Glass, said Jake Steinerman, one of the app’s lead developers. The IR sensor can detect winks and blinks, and the tilt sensor can measure how a user’s head is oriented, he said. Both of those metrics were used for Steinerman’s team to develop a formula that could determine if someone is falling asleep, he said.

“Alert, it appears you are falling asleep,” the notification might say. The wearer can then tap twice on the Glass unit to be directed to the nearest rest area.

The software is still in beta. The developers even admit on the app’s homepage that this may not work all that well. “[DriveSafe] is not guaranteed to stop you from falling asleep while driving and should not be relied on to do so,” a disclaimer says.

Google could not be immediately reached to comment on the software, and whether it falls in line with their developer policies. Google could fall either way on it—in November the company updated its terms of service to say that its services should not be used in a way that distracts people or prevents them from obeying traffic laws.

The app’s introduction marks a curious development for Glass, given that the device itself could be seen as a distraction. Glass has to be “on” for the software to work, so it’s possible users might be getting other notifications while using it.

The legality of using Glass while driving is also unclear. Late last year a woman in California was ticketed for wearing Glass.

DriveSafe is still in its early stages. It is not yet available in Google’s official MyGlass store; users must “sideload” it into Glass using a fairly technical process. “When we feel DriveSafe is ready for drivers, we’ll submit it to the MyGlass store,” Steinerman said.