Breathalyzers are standard over here, and pretty much never an issue. We have tolerances defined in the law (few digits get substracted by default from the meas

Breathalyzers are standard over here, and pretty much never an issue. We have tolerances defined in the law (few digits get substracted by default from the measured number), then depending on the alcohol level, if you're above the legal limit, you get fined and/or lose a licence (depends on the alcohol level, is it a normal car, or driving a truck/bus, young driver, etc.). If you disagree with the measured result, the police can drive you to a nearby doctor/emergency room, and they do a blood test, but since it's more accurate with less assumed error tolerances subtracted, it's usually not worth it (unless you're just above the "losing your licence" limit, and hopefully your metabolism is faster at burning alcohol than the doctors charts assume. Everyone else in the car can be drinking while you're driving and blowing in the breathalyzer, and it's not an issue. I trust a device with proper calibrated sensors much more than an officer that has to fill out his quota or wants to fine me for some other stupid reason.