Marijuana Behind the Wheel.

• Author: Thiede, Brian

FEDERAL LAW PROVIDES a system of classifying both prescription and recreational drugs based on their harm to users and harm to society. (1) The ultimate purpose of this drug classification system is public safety. The Controlled Substances Act (CSA) defines a Schedule 1 drug as one that has a high potential for abuse, has no currently accepted medical use in treatment in the United States, and lacks accepted safety for use under medical supervision. (2) Marijuana is a Schedule 1 drug. (3)

In 2015, over 35,000 people were killed in traffic crashes. (4) Nearly a third of those involved an impaired driver. (5) The National Roadside Survey conducted by the National Highway Traffic Safety Administration (NHTSA) demonstrates the increased use of marijuana by our nation's drivers. In the 2013-2014 roadside survey of weekend nighttime drivers, 8.3 percent had some alcohol in their system and 12.6 tested positive for THC (6)--up 48 percent from the number in 2007. (7) Since a majority of states have legalized marijuana for medical and/or recreational use, (8) marijuana-impaired driving cases will continue to present unique challenges for prosecutors and law enforcement.

Marijuana is the most commonly used illicit substance (9) and has become the most commonly detected non-alcohol substance among drivers in the United States. (10)

Generally, impaired driving statutes allow for prosecution of a person who drives (1) while impaired by alcohol, drugs, or any combination thereof, (2) while having a specified level of alcohol in his or her system, or (3) while having any measurable amount of alcohol or drugs in his or her system (e.g., zero tolerance).

Numerous scientific studies demonstrate the relationship between alcohol and the impairment of driving function supporting these "per se" laws. There are challenges, how "per se" laws.

It is difficult to parse out statistical information about impaired driving prosecutions in which marijuana was the impairing substance or even the broader category of drugs in general. This is largely the result of how impaired driving laws are written. Generally, a prosecutor does not need to "prove" what the impairing substance is, only that it impaired the driver. This can be done with circumstantial evidence as well. For example, a driver who exhibits clues of impairment and is found to have a "bong" in his or her car as well as a bag containing a green leafy substance could be successfully prosecuted for DUI even without any chemical test to prove marijuana in his or her system. To change current laws to add a separate...