The prosecution must prove a driver charged with marijuana DUI lacked the "ability to drive with the caution characteristic of a sober person of ordinary prudence under the same or similar circumstances." Basically this means the prosecutor needs to show the person's ability to drive was impaired because of their use of marijuana. In order to prove a person is guilty of marijuana DUI in court, the prosecutor will use two groups of evidence: 1) the investigating officers' observations of the driver, such as bad or erratic driving, the physical appearance of the driver, their mental awareness, performance on field sobriety tests, the presence of marijuana in the car, particularly joints or other paraphernalia to show recent use, and any incriminating statements the driver makes, such as admitting that they recently smoked; and 2) analysis of the driver's blood for THC, the active ingredient in marijuana.
Unlike California law related to alcohol DUI cases, which a driver is presumed to be DUI if they have a blood alcohol content of .08 or greater, and that test is taken within 3 hours of driving, there is no "per se" amount of marijuana in one's system that leads to the presumption that the driver's ability to drive is impaired by marijuana and, therefore, he or she is DUI. This makes it much more difficult for the prosecutor in a criminal case to prove beyond a reasonable doubt that the driver's ability to drive was impaired. Of course, if THC is detected in the driver's blood the prosecutor will argue that the driver was "high" at the time of driving. However, having positive metabolites for marijuana does not mean that you are impaired. Marijuana can remain in a person's system for weeks. Further discussion of the problems with marijuana blood tests can be found on our Marijuana DUI page.
One of the problems facing drivers who smoked marijuana earlier in the day is that they may still smell of marijuana after all of the psychoactive affects have worn off. If the person is stopped by the police the officer will likely still suspect the person has recently smoked marijuana and, therefore, is high and DUI. Once the officer makes that assumption, he will commence a DUI investigation and try to obtain as much evidence as possible to support this assumption, such as the field sobriety tests, to make the case that the driver is DUI. This is why it is important to hire a good DUI attorney if you are arrested for marijuana DUI. DUI Lawyer Robert D. Berglund zealously represents his clients accused of marijuana DUI by attacking the credibility and accuracy of the prosecution's evidence. Not only are there problems associated with the blood tests but the field sobriety tests that are used were designed for alcohol DUI cases. Absent other aggravating factors of impairment, such as erratic driving and/or an accident, DUI Lawyer Robert D. Berglund may be able to get the DUI charge either dismissed or reduced to a lesser offense. If you have been arrested on suspicion of marijuana DUI, CONTACT our office today for a free and confidential consultation.