"I've only had a few, I'm fine to drive." It's the age-old line heard many times by friends, family and bartenders questioning the sobriety of someone about to get behind the wheel.
There are few things harder than talking sense into a stubborn drunk, let alone convincing him that he shouldn't drive, but maybe this will help. It's a new app for the iPhone called BreathalEyes, which detects involuntary eye movement to let potential drunk drivers know when they've had a few too many.
By using the iPhone's camera, the app records a person's Horizontal Gaze Nystagmus (HGN), a condition where the eye involuntarily jerks and twitches when a person looks to their right or left while holding their gaze. HGN can be caused by alcohol consumption and those suffering from it are unaware it's happening. This is why officers commonly check for HGN during field sobriety tests.
Legally intended for "entertainment purposes only," BreathalEyes was tested alongside a breathalyzer and found to have an effective range of 0.02 — 0.18 percent, with (+/-) .02 percent accuracy of blood alcohol content (BAC) levels. That percentage may not sound like a lot, but any proof that convinces someone who's drunk not to drive is good enough.
The test requires a steady-handed sober person to administer it in good lighting conditions, so stepping aways from the dimly lit bar is at least a step in the right direction.
The BreathalEyes app is compatible with the iPhone 4 or later and is now available for $0.99. An Android version is expected later this year.