I know about ignition interlock devices – my company provides these – and there is a little more nuance to it than that.
Firstly (and depending on jurisdiction), IIDs have to pass fairly rigorous verification in an accredited laboratory before they are accepted for use.
Secondly, all IIDs are regularly (every one to two months) calibrated against ethanol/nitrogen gas certified to a set level, to ensure accuracy.
In contrast, police breathalysers are usually calibrated every 6 to 9 months.
This is well and good, but ethanol is also present in miniscule quantities in a vast array of foods and drinks, in addition to beer, wine and spirits.
If someone has consumed these in the past couple of minutes, then takes a test, it will detect the ethanol.
Some examples that people commonly report using in vehicles, which all contain ethanol:
- anything fermented. Kombucha, ginger beer
- fresh bread, pizza, doughnuts [1][2]
- mouthwash, hand sanitiser
- some medications, including asthma medications
These are common everyday items, leading to an ethanol-detecting device detecting ethanol in a substance that contains ethanol.
From the user perspective, this is a false positive.
From a technology perspective, this is working exactly as it should be.
Fourthly, alcohol readings caused by mouth contaminants aren't a surprise. Any sane jurisdiction will allow the user to take another test within a few minutes to prove they hadn't ingested alcohol (mouth contaminations will clear from the mouth within a few minutes, whereas ingested alcohol will show another alcohol reading).
To summarise: breath alcohol testing is an established technology with high standards to meet; ethanol is widely prevalent leading to IIDs detecting ethanol; recourse is available to prove the ethanol detected wasn't ingested alcohol.
Firstly (and depending on jurisdiction), IIDs have to pass fairly rigorous verification in an accredited laboratory before they are accepted for use.
Secondly, all IIDs are regularly (every one to two months) calibrated against ethanol/nitrogen gas certified to a set level, to ensure accuracy. In contrast, police breathalysers are usually calibrated every 6 to 9 months.
Thirdly, all breath alcohol testing devices (IIDs, fuel cell breathalysers, evidential infrared breathalysers) detect ethanol.
This is well and good, but ethanol is also present in miniscule quantities in a vast array of foods and drinks, in addition to beer, wine and spirits.
If someone has consumed these in the past couple of minutes, then takes a test, it will detect the ethanol.
Some examples that people commonly report using in vehicles, which all contain ethanol:
- anything fermented. Kombucha, ginger beer
- fresh bread, pizza, doughnuts [1][2]
- mouthwash, hand sanitiser
- some medications, including asthma medications
These are common everyday items, leading to an ethanol-detecting device detecting ethanol in a substance that contains ethanol. From the user perspective, this is a false positive.
From a technology perspective, this is working exactly as it should be.
Fourthly, alcohol readings caused by mouth contaminants aren't a surprise. Any sane jurisdiction will allow the user to take another test within a few minutes to prove they hadn't ingested alcohol (mouth contaminations will clear from the mouth within a few minutes, whereas ingested alcohol will show another alcohol reading).
To summarise: breath alcohol testing is an established technology with high standards to meet; ethanol is widely prevalent leading to IIDs detecting ethanol; recourse is available to prove the ethanol detected wasn't ingested alcohol.
[1]: https://en.m.wikipedia.org/wiki/Ethanol_fermentation [2]: https://cooking.stackexchange.com/questions/22237/does-bread...