Smartphones have become our first world Swiss Army Knife, they can tell the time, tell us where we are and how to get somewhere, play music and video, access the internet, oh and we can call people on them…
But now science has found a way to measure if you’re drunk, using the inbuilt pedometer on your phone. A pedometer works by detecting the motion of a person’s hands or hips in order to calculate whether they have taken a step.
In this particular experiment participants were asked to consume vodka – naturally! The subjects had an hour to finish enough vodka to get their Breath Alcohol Concentration (BrAC) to 0.20, nearly three times the legal limit.
“We really wanted to have enough data points over the threshold of the legal limit of alcohol, which is 0.08,” says study lead author Brian Suffoletto.
Before the alcohol consumption began the subjects had regular smartphones strapped to their lower backs and completed a short sobriety test of 10 steps forwards, about face and 10 steps back. This was then repeated after the vodka, once every hour for 7 hours to measure the difference in gait as the effects of the alcohol began to wear off.
By analysing the motion data captured by the phones using mathematical models, the team was able to compare each person against his sober self.
“We found that, really, what was driving the model is the medial-lateral sway,” said Suffoletto. “Which kind of makes sense when you think about the caricature of the drunk cartoon, a figure who kind of is swaying back and forth”.
The mathematical model used to analyse each person is 90% accurate and shows real promise, with the team now looking to find a way of getting the technology to work whilst the phone is in someone’s hand or pocket.
This is a huge step in terms of safety, imagine the apps that could be developed from this. How useful would it be if your phone automatically sent you a notification passed a certain intoxication level for example, it would alleviate the stress of having to make potentially dangerous decisions later on.
The drink drive limit in England, Wales and Northern Ireland is 80mg of alcohol per 100ml of blood. This figure cannot be safely converted into units because people process alcohol differently depending on individual tolerance, body mass and gender.
Some people could be drunk after even just one pint or a glass of wine. So having a tool like this in your pocket would be invaluable, have I had too many to drive? Imagine the convenience of opening an app that could tell you, much better than carrying around a portable breathalyser!
Police have long used gait analysis as an in the field indicator of drunkenness, so this longstanding reputation could be built upon with the development of a handy and potentially lifesaving app.