Right now, no clear way exists to tell when a motorist has too much marijuana in his or her system to drive. The limits that have been set for blood alcohol content in Colorado and other states are rather useless in determining if someone should be arrested and charged with DUID. This is because THC, which is the compound present in cannabis that alters the mind, dissolves in fat, while alcohol actually dissolves in water.
Because THC dissolves in fat versus water, it is absorbed very differently from how alcohol is absorbed, so a Breathalyzer is not helpful for detecting it. When people drink, alcohol spreads through their breath and saliva, even saturating their blood and lungs. Thus, measuring the amount of alcohol in one area of the body can indicate how much alcohol is in other areas of the body, including the amount impacting the brain. However, marijuana does not work like this.
For marijuana, the height of one’s intoxication is not at the time when the THC levels in the blood peak. In addition, the high does not rise and then fall uniformly according to how much of the compound enters and leaves a person’s bodily fluids. Furthermore, research shows that THC can still be measured in a person’s brain–which is fatty tissue that easily soaks up THC–even when the compound can no longer be measured in the blood. Scientists continue to try to find ways to measure pot intoxication levels, all while legislators seek to rapidly identify and then penalize individuals who have consumed to much marijuana to drive.
If a person in Colorado is reportedly found to be operating a vehicle while too high to do so and is then arrested for this, he or she has the right to fight his or her DUID charges in court. The individual may also be given the opportunity to plea bargain with the prosecution, which may lead to a lighter sentence than what he or she would receive in court. The criminal defense will push for the most favorable outcome for the individual while also making sure that his or her rights are safeguarded during the criminal proceeding.
Source: npr.org, “Why Is It So Hard To Test Whether Drivers Are Stoned?“, Angus Chen, Feb. 9, 2016