Not so long ago, Driving Under the Influence (DUI) was synonymous with drinking and driving. That is no longer the case. In addition to alcohol, Pennsylvania prohibits driving with any amount of certain controlled substances in your system, regardless of whether the driver is actually “under the influence” of that drug, or the drug negatively impairs that person’s ability to drive. By far the most prevalent of these is Marijuana. To fully understand the interplay between Marijuana and Pennsylvania’s DUI laws requires a basic understanding of the elements of a Marijuana DUI.

While technically Marijuana is broken down into three components, the most relevant of these are Delta-9 THC (active component) and Carboxy-Delta-9-THC (inactive component). Simply put, Marijuana’s active component is the part that makes its user feel “high”. Generally speaking, Marijuana enters a person’s system, and its effects are almost immediately felt, producing a “high”. The active component then leaves a person’s system as does its effects on the driver, and becomes undetectable within several hours. What remains detectable for several days and possibly even weeks, however, is the inactive component.

The unique and ironic part of Pennsylvania’s often archaic controlled substance DUI laws is that there is universal agreement amongst toxicologists that the inactive component has absolutely no effect on a person’s ability to drive a motor vehicle. None. Nonetheless, having any amount of the inactive component (yes, the part that has no negative effect on a person’s ability to drive) in a driver’s system, so long as it is above 1 nanogram per milliliter, can cause a person to be convicted of DUI. Given that the inactive component can often stay in a person’s system for weeks after smoking, these facts could clearly result in a conviction for a Marijuana DUI despite having not smoked anytime recently, nor having displayed any adverse effects.

Therefore, the main area of concern for any individual charged with a Marijuana DUI is one of time: when is the last time that person smoked Marijuana just prior to driving, and when is the last time he/she smoked in the days leading up to the arrest. Both answers are relevant to any defense to a Marijuana DUI charge. Again, if there is any amount of either the active or inactive Marijuana component in the person’s blood (over 1ng for the inactive, or over .4 ng for the active), this is a per se DUI. Stated differently, there is no need for the Commonwealth to show that the driver was actually under the influence of the Marijuana at the time of driving, or that his/her driving was negatively affected by the smoking. While this still leaves other defenses as being available to the driver, merely saying “But I wasn’t high” is not going to be helpful to the driver’s cause.

The message of Pennsylvania’s DUI law is clear: no amount of Marijuana is acceptable to have in a driver’s blood. Whether or not the Marijuana negatively impacts a person’s ability to safely operate a motor vehicle is wholly irrelevant to the question of guilt in defending a charge of a Marijuana DUI in Pennsylvania.

Dan Bush is a criminal defense attorney at Lamb McErlane’s West Chester, PA location. He chairs Lamb McErlane’s criminal litigation department and is a partner in the firm.  Dan is a former prosecutor in the Chester County District Attorney’s office who has twenty years of experience prosecuting and defending individuals charged with a crime.

Contact criminal defense attorney Dan Bush at dbush@lambmcerlane.com. 610-430-8000.