Ignition interlock devices prevent drivers from starting their vehicles if its alcohol breath tester detects alcohol or various other substances in the driver’s breath.
However, some ignition interlock devices prevent heavy dieters who haven’t had a sip of alcohol from starting their vehicles, according to the Swedish medical journal, Lakartidning. The problem is that dieting can cause an increase of acetone in breath, causing the sensor to falsely detect alcohol.
A spokesperson from The Swedish Road Administration said the device also “reacts with other materials, like cigarette smoke.”
Ignition interlock devices are sometimes used on cars of persons convicted of driving while impaired or intoxicated. One automaker is planning to install them on all the vehicles it manufactures.