Though marijuana has been slightly decriminalized in Mississippi, residents should exercise caution, and they should never drive with illegal substances in the car. Not only is it illegal to drive under the influence, but police in other states have been arresting people for drug possession based on the results of roadside drug tests, even though these tests are unreliable.

Multiple convictions overturned due to faulty drug tests

This year, Clark County in Nevada disclosed that it overturned five convictions in 2017 that were based on incorrect roadside drug test results. The roadside drug tests, performed by police officers, showed that five individuals were in possession of cocaine. As a result, these individuals pled guilty to drug charge possessions. Later lab testing showed that the substances were not actually cocaine or any other illegal substance.

Clark County is not the first to overturn wrongful convictions based on these roadside tests. A county in Oregon also overturned five convictions, and Houston, Texas overturned over 250 convictions.

How do the tests work?

Cops like roadside drug tests because they are relatively cheap (about $2 each) and easy to use. Officers take a sample of the suspected substance and put it into another liquid, which is supposed to turn a particular color if the substance is an illicit one, like cocaine or methamphetamine. Though it sounds relatively straightforward, lab officials have acknowledged that officers sometimes misinterpret the results.

Roadside tests are used in questionable ways

Many judges refuse to allow evidence of roadside drug test results at jury trials because they are unreliable. Studies have also shown that, while the tests are accurate enough to establish “probable cause” for an arrest, they are not accurate enough to support a guilty verdict, which is based on a higher standard. Nonetheless, prosecutors use the results of these tests to persuade defendants to plead guilty to lesser sentences. Once someone pleads guilty, police often destroy the evidence, so the substance cannot be retested by a lab. For this and other reasons, it is always recommended that someone consult with a criminal defense attorney well-versed in criminal law before entering into a plea deal.