Home » Blog » DWI / DUI » Breath testing technology is unreliable and relies on humans to check the machines

Breath testing technology is unreliable and relies on humans to check the machines

Highly-rated Fairfax County/Arlington/Northern Virginia DWI/criminal defense lawyer pursuing the best defense. Since 1991.

Call Us: 703-383-1100


Breath testing should not be permitted to obtain a drunk driving/DWI conviction. Blood testing is superior, whereby breath testing machines can deliver falsely high readings for such factors as presence of mouth alcohol (whether occasioned by food, dentures, tongue rings, acid reflux, or vomit burps, for instance), elevated mouth temperature, unreliable dry gas standards or alcohol simulator solutions used as control mechanisms to check the machines for accuracy, error by the makers of the machinery, error by those examining and maintaining the machinery, and those operating the machinery.

What happens when a police department relies on only one employee to maintain and certify its breath testing machines and that employee quits his or her job? Unless the employee finds a suitable replacement, the machines must be put to pasture once they are out of certification or need repair.

That is precisely what has happened in the District of Columbia, whose breath testing machine certifier recently quit. Consequently, seven of the District of Columbia police department’s eight breath testing machines are out to pasture, leaving the remaining machine to go that route unless the quitting employee is replaced.

Apparently, urine testing will increase for D.C. DWI investigations as a result of fewer breath test machines being available. Wisely, Virginia law does not provide for urine testing to prove DWI charges, but District of Columbia law does, even though its then-acting toxicologist confirmed in 2011 that little correlation exists between urine alcohol concentration and blood alcohol content. A forensic toxicologist who has testified for my clients explains that alcohol concentration in the urine can wildly fluctuate depending on how dilute the urine is, seeing that water content can wildly fluctuate in the bladder.

What is the solution to the inaccuracy of breath testing and urine testing for blood alcohol content? Strike the admissibility of breath and urine testing and only allow blood test results.

What should suspects do when asked or told to submit to breath, blood or urine testing in DWI investigations or arrests? Weight the costs and benefits of refusing such tests against the possible risks of losing driving privileges or being charged with an additional offense for refusing such testing.