The AAA Foundation for Traffic Safety commissioned a study that looked at how several states where marijuana is legal determined whether a person was impaired by marijuana usage while driving. The study found the tests used to determine impairment were scientifically flawed. While marijuana is not legal in Kentucky, the report's findings might still be of interest to some Kentucky drivers. According to AAA, the tests create a risk of prosecuting people who are not doing anything unsafe while allowing others who are impaired to go free.
The problem with the tests is that it is not possible to correlate THC levels to impairment in the same way that blood alcohol content can be. A person might have a high level of THC in his or her bloodstream and be driving safely while another person might have low levels but still be impaired. The AAA has recommended that instead of tests for THC, states should use officers who are specially trained to recognize drivers who are impaired by marijuana usage.
A driver's behavior, tongue color and pupil dilation are among the many tests that a trained officer would use to determine whether the driver was impaired. According to one professor who specializes in drug issues, marijuana usage may double the likelihood of a crash.
Any amount of marijuana usage in Kentucky may create legal problems for a person, but this does not mean that there are not various defenses that a defendant's attorney can assert. These can include challenging whether the search that led to the seizure of the drug was made without probable cause.
Source: CBS News, "Tests for Driver Impairment by Marijuana Flawed: AAA," May 10, 2016