Driving While Under the Influence of Bread

Here’s some­thing that’ll make you think twice about eat­ing fast food while dri­ving. The video below shows inves­ti­ga­tors obtain­ing an breath alco­hol read­ing of 0.025 from an alcohol-free sub­ject, who recently ate a piece of bread. That’s right, no alco­hol in his sys­tem, just bread.

It’s a known prob­lem for breath ana­lyz­ers (the Intoxilyzer 8000 is shown in the video below), includ­ing the old Intoxilyzer 5000. Arizona DUI attor­ney Lawrence Koplow has posted on this sub­ject in his blog, and about this video in par­tic­u­lar here.

The issue of false pos­i­tives like the one obtained from eat­ing bread is why it’s so impor­tant that a depri­va­tion period of 10 to 15 min­utes passes before a sub­ject is allowed to blow into any breath tester after hav­ing any­thing in his mouth. If the sub­ject puts any­thing into their mouth, either by plac­ing it into the mouth, or by regur­gi­ta­tion, the depri­va­tion period must be started all over again. This also means that a true depri­va­tion period requires the police offi­cer to actu­ally watch the sub­ject dur­ing that 15 min­utes — not drive a car, or fill out stacks of paper­work in another room.

So, if you’re stopped and asked to give a breath sam­ple, be sure to not put any­thing in your mouth before the test is admin­is­tered. That includes your fin­gers, chew­ing tobacco, a bite out of a Big Mac — not any­thing. If this guy can blow a 0.025 BrAC read­ing from eat­ing white bread, there’s no telling what kind of read­ing could be obtained from other substances.