Impaired driving is against the law. People should not try to operate motor vehicles when they know alcohol has affected their abilities or when their blood alcohol concentration is over the legal limit.
There are many types of evidence that police officers can collect to prove that drunk driving occurred. Frequently, officers follow other vehicles in traffic to record footage of a motorist’s inability to safely operate their vehicle. Other times, they may administer field sobriety tests to collect evidence.
Alcohol tests are also a key form of evidence. Particularly when the testing involves a breath sample provided on the side of the road, there may be reasons to question the accuracy of test results. In some cases, there could be a medical explanation for the failed test.
Why can breath tests fail?
Chemical breath tests look for the presence of certain types of compounds. Alcohol is not the only substance that could trigger a positive result on a breath test. For example, certain medications, such as asthma inhalers, could cause false positive results.
People with uncontrolled diabetes or those following special diets could have acetone in their exhaled breath, which could cause a false positive. People who know they had not consumed alcohol, or at least not an excessive amount, may need to review their medical records to determine if there is a reasonable explanation for why they failed the test.
Presenting medical evidence during a trial could raise a reasonable doubt about the accuracy of chemical evidence. Those hoping to fight drunk driving charges often need help developing a realistic defense strategy that limits their chances of a conviction.