New Yorkers may be surprised to read that numerous convictions have been overturned in the past few years in multiple states due to faulty roadside drug tests. Roadside drug tests are used by police to quickly check whether a substance is illegal. Police use the test by mixing a substance with a liquid that, in theory, should change colors based on what the substance is. In practice, this test can result in false positives, and it is so inaccurate that many judges will not allow evidence of the test results at trial.

In 2017, Clark County in Nevada overturned the convictions of five men for cocaine possession after a lab determined that the powders were not actually cocaine or any illegal substance at all. These exonerations followed similar exonerations of multiple defendants in an Oregon county and over 250 exonerations of convicted defendants in Houston, Texas.

The men whose convictions were overturned in Clark County had pleaded guilty to drug charges in order to receive lesser sentences. Four of the defendants avoided jail time altogether and the fifth was sentenced to eight months in jail. The five defendants were notified by the district attorney once a lab determined that the roadside drug test results were inaccurate.

One study found that roadside drug tests are accurate enough to justify an arrest since the standard there is “probable cause.” However, since the standard for a guilty conviction is “beyond a reasonable doubt,” the roadside tests are insufficient to support a guilty verdict. Knowing this, prosecutors may pressure unknowing defendants to plead guilty before trial by threatening to use the drug test results, despite knowing the judge may not allow this. This is just one example of why defendants should not speak with the police or prosecutors following an arrest without talking to a criminal defense attorney.