Driving under the influence charges in New York include any substance that impairs driving ability. Roadside sobriety tests for drunkenness can help prosecutors, because a failure can be used as evidence in a DUI case. But there is a question of whether sobriety tests work as a test for being high on marijuana. Some defense lawyers argue that they don't, and that they should not be allowed as evidence in marijuana DUI cases.
The argument over sobriety tests for being high has been taken to the Massachusetts highest court, with defense and prosecuting attorneys taking opposite sides. One defense attorney told the court that there is no evidence that tests for alcohol intoxication work for marijuana intoxication, while a prosecuting attorney argued that there is such evidence. She said there are three investigations that the court should consider.
Meanwhile, a professor at Columbia University noted a scientific fact that makes marijuana intoxication testing difficult. Marijuana can show up in people's systems days after they used it, meaning it could show in a blood test long after the person has ceased being under its influence. An iPhone app has been created that tests for symptoms of marijuana intoxication, like slow response time and inability to perform tasks that require divided attention. The app is being tested for reliability, while experts predict that science will soon come up with many ways to test for marijuana impairment.
People who have been charged with DUI may think failing a sobriety test means they have no recourse, but this is not true. Positive test results can be used as evidence by the prosecution, but they do not prove guilt, and a defense attorney will often have ways to challenge them.