The problem with chemical tests for driving impairment

Impaired driving, which is the legal term for driving while under the influence of intoxicating compounds like alcohol or drugs, is a serious problem on the modern roadways. Most people think of alcohol when they think of impaired driving. However, prescription drugs and recreational substances also play a role in impaired driving issues.

Unlike with alcohol, which has a roadside breath test to help law enforcement officers detect and prove impairment, chemical impairment related to prescription or recreational drug use is harder to verify. Even though there are testing methods available, these are not always as reliable as people might imagine.

Urine tests tend to show previous drug use

Urine is a way for the body to excrete compounds it no longer needs. That could include excess sugars, as well as the metabolites from any substances you have recently ingested. Depending on the chemical compound, a person could have a positive urine test weeks or even months after consuming a drug.

For that reason, urine tests are highly suspect when it comes to establishing impairment in drivers. However, law enforcement officers can and do still order urine tests related to impaired driving arrests. They can potentially use those tests against someone in court.

A criminal defense attorney may be able to help you devise a strategy that raises the question of whether simply having metabolites in your urine is adequate evidence to prove impairment behind-the-wheel at a specific time.

Blood tests may not always show everything

Some states will use blood tests to look for drugs other than alcohol in someone’s system. Others will use blood tests for alcohol as well. People tend to think of blood tests as the most reliable and accurate. However, even a blood test may have inaccurate results.

First of all, just as urine tests may show drug use long after the fact, blood tests may not show drug use immediately after someone ingests a substance. Not only that, but there are many compounds that simply do not show up properly on blood tests, including popular designer or synthetic drugs.

Chemical tests simply aren’t as accurate or reliable as many people think they are. Despite the hype of police television shows, even experienced officers can make mistakes in administering or interpreting chemical tests. This is good news for anyone facing an impaired driving charge.

Law enforcement officers may perform the wrong kind of chemical test, or they may perform that test improperly. The way that police handle evidence in a case can have a direct impact on whether that evidence matters in court. A criminal defense attorney can review the scenario of your arrest, and the paperwork and evidence the state has, in order to help you strategize when facing impaired-driving allegations.