When police pull you over and suspect you of drunk driving, they may ask that you participate in field sobriety tests and a roadside breath test. They present these options with such authority that you may participate, and when the breath-testing machine indicates that your blood alcohol concentration meets or exceeds the legal limit of 0.08 here in Texas, the officer places you under arrest.
You may feel as though, since the breath test indicated illegal impairment, that the officer has you "dead to rights." Don't make that mistake. Roadside breath testing machines are notoriously inaccurate -- so much so that the results are often not admissible in court.
Why would the machine not give correct readings?
Any equipment or technological device used by anyone, including the police, only works when conditions are right. The problem with roadside breath testing machines is that the conditions are often not right, and the following issues could skew your results:
- Using a breath-testing machine may not necessarily require a great deal of skill, but it does require attention to detail. If the officer fails to pay attention or fails to conduct the testing properly, it could yield false results.
- Another step the officer could miss is running the test multiple times in order to see if the readings are consistent. Relying on just one result almost guarantees the results aren't accurate.
- Failing to calibrate the machine also increases the potential for bad results.
- Failing to change the batteries could skew results as well.
- Even portable breath testing machines have software that could have glitches and bugs, which would affect the outcome of the testing.
- If an officer does the breath test in an area\ where certain environmental factors such as varnish or paint fumes exist, it will more than likely cause false results.
- In addition to environmental factors, foreign substances in your body could cause inaccurate results. For example, mouthwash, toothache medicines and breath fresheners may have alcohol in them and cause bad results.
Your health or diet could also make getting accurate results nearly impossible. As you can see, you have no reason to believe that the officer's portable breath testing machine produces error-free readings. If you do end up under arrest on suspicion of drunk driving due to the results of a roadside breath test, challenging the results will more than likely be the first step. If the officer's probable cause was the results of this test, it could have a substantial effect on your case.