How Breathalyzers Work

Breath alcohol analyzers, commonly called ‘breathalyzers’, are devices used to estimate blood alcohol content (BAC) from breath samples. These instruments are often used by law enforcement officers in the United States when they have stopped a driver who they believe has been driving a motor vehicle while drunk. Although breath analyzers do not measure blood alcohol content or concentration directly, which requires a lab analysis of a blood sample, they estimate BAC by measuring the amount of alcohol in one's breath. Although these devices are generally accurate, there are a number of calibration, administration and outside influences that can produce inaccurate results.

Hand-held field testing breathalyzers are frequently used by police officers when they pull over a driver suspected of DUI (Driving Under the Influence), as part of ‘field sobriety testing’. The results of a positive field breath alcohol reading can be used to prosecute drunk drivers. Unless the accused drunk driver refuses to submit to the breathalyzer test, he will be charged with a misdemeanor offense of operating a motor vehicle with a BAC of .08% or higher. It is important to note that in most states the maximum allowable BAC for drivers under the age of 21 is only .02%! You also can refuse a breathalyzer.

Breathalyzer Results in the Courtroom

The breathalyzer reading will be offered as evidence that the driver of the vehicle was legally intoxicated. Some jurisdictions now allow the use of breathalyzer test results regardless of how much time passed between operation of the vehicle and the time the test was administered. Although breathalyzer test results are not always needed to prove that a defendant was driving under the influence, laws in most states require the jury to presume that a driver was under the influence if his BAC was over .08% when driving. However, a jury can disregard the test if they deem it unreliable or if other evidence establishes a reasonable doubt.

If a driver refused to take a breathalyzer test when pulled over by police, most states allow evidence of that fact to be introduced during the trial. In fact, in many states, the jury is instructed that they can draw a permissible inference of guilt by this action. Many states operate under ‘implied consent’, meaning that anyone issued a driver's license in that state automatically agrees to submit to a test of his breath, blood or urine when requested by a law enforcement officer. Failure to submit to such a test may result in automatic suspension of one’s driver's license even if not convicted of drunk driving. Failure to submit to such a test may also serve to enhance the penalties for a drunk driving conviction.

Hiring the Best Possible DUI/DWI Defense Attorney

The complexity of handling most DWI (Driving While Intoxicated) cases is precisely why it is so important for you to hire the best possible DUI/DWI defense attorney. And, since the laws on DUI vary significantly from state to state, it is vital that you hire a lawyer who is familiar with the DWI laws in the state in which you were cited. A common mistake that individuals who are new to the justice system make is hiring a lawyer who does NOT specialize in DUI defense. Many people are under the mistaken notion that all defense attorneys are proficient in DUI defense. This is not the case with the majority of criminal defense attorneys. It is imperative that you interview and hire a highly-trained DWI defense attorney, one with whom you feel comfortable and confident as he takes you through the various aspects of your court appearances and DMV (Department of Motor Vehicle) hearings.

Breathalyzers for the Consumer Market

There are also breath alcohol analyzers that are intended for the consumer market that are less expensive and usually much smaller than the devices used by law enforcement. Although they somewhat less accurate, they still give a useful indication of the user’s BAC. These devices that are sold in the United States are required to be certified by the Food and Drug Administration (FDA).

If you or a loved one is facing a potential DUI charge, please fill out our secure free legal evaluation form and one of our DUI attorneys will contact you immediately. Or call us toll free at 800-798-8384. You can rest easy knowing that your information will remain confidential and that your legal concerns are being addressed by the best possible DWI lawyers.