How can an ordinary person be expected to obey the law, unless he or she has a pocket breathalyzer to measure the level of intoxication?
All drivers rely on speedometers to keep driving speed within the legal limits. What if cars came without speedometers and the police still enforced speeding laws with high tech radar guns? It would be very difficult to tell what a particular speed feels like if you never had your speed tested, nor had any previous experience with going 30 mph, for example. Not many people really know what .08% BAC feels like, unless you have a way to get it measured.
Breath analysis is the most common method of testing for blood-alcohol content (BAC) in use today. A pocket breathalyzer estimates the concentration of alcohol in the body by measuring the amount of alcohol exhaled from the lungs.
Breath alcohol tests have been proven reliable and efficient. Having the correct information is important when making the dangerous and potentially life threatening decision to drive after a few drinks.