Though marijuana has been decriminalized in some cities of Pennsylvania, it is still illegal as is driving while under the influence of marijuana. Police have been using less-than-perfect tests to determine if a driver is under the influence of marijuana, but that is not all: In many parts of the country, officers have been relying on second-rate roadside drug tests to determine if powdery substances on a suspect’s person are illegal.

What are roadside drug tests?

Roadside drug tests are cheap and quick methods that police use to determine if there is probable cause to make an arrest. To use the test, officers take a sample of the substance in question and mix it with a chemical that is supposed to change colors depending on what the substance is. These tests are far from accurate. On top of that, officers sometimes misinterpret the tests.

Convictions have been overturned due to faulty tests

Clark County in Nevada reported that five convictions were overturned in 2017 based on lab tests showing that substances believed to be cocaine based on roadside drug tests were not in fact illegal substances at all. This was not the first time that this occurred: Multnomah County in Oregon also overturned five convictions, and Houston, Texas, overturned over 250 convictions based on similar tests.

How can roadside tests be used to get a conviction?

Many judges refuse to allow evidence of roadside drug test results given the inaccuracy of the tests. Studies have concluded that the tests provide sufficient “probable cause” for an arrest but are insufficient to justify a conviction. Nonetheless, prosecutors continue to wield roadside drug test results as a weapon against criminal suspects, and they often convince the accused to plead guilty based on the threat of a longer prison sentence should they be convicted at trial.

Individuals who have been accused of a crime should not be coerced into a plea deal based on data that may not even be admissible at trial. If you have been charged with a crime, it may be a good idea to consult with a criminal law attorney before speaking with the police or prosecutors.