As cannabis continues to be legalized throughout the United States (both for medical reasons and recreational use), it has proven important to both lawmakers and police officers to find a way to test the impairedness of a driver who has THC (tetrahydrocannabinol) in their system. The main issue with finding a standardizing level of THC-impairedness is that THC is not processed in the same way as alcohol. While the legal limit for alcohol is easy to measure at 0.08 using proven devices, it is difficult to determine a specific amount of THC that encompasses its effects for everyone who uses it.

What is THC?

Tetrahydrocannabinol (THC) is a chemical responsible for producing most of the psychological effects of smoking and consuming marijuana. The chemical effects of cannabinoid receptors concentrated in specific areas of the brain that are known to affect memory, thinking, coordination, pleasure and time perception. While the human body naturally makes cannabinoid chemicals, the compound THC can also be consumed or inhaled from the resin in the glands of marijuana plants. The chemical stimulates brain cells to release dopamine which in many creates euphoria along with other stated side effects.

Determining how much THC in the body is too much is challenging. Many states consider five nanograms per milliliter of blood of THC to be the limit for marijuana. However, a regular marijuana user could accumulate this level of THC in their blood and not be impaired at all. On the other hand, an occasional user may be impaired but have a lower amount of THC in their blood. Additionally, taking someone into a police station and having them wait hours to take a blood test gives the THC time to leave the bloodstream in sufficient quantities is to render testing useless. Overall, measuring THC-impairedness through blood tests has not yet been proven to be accurate.

Instead, law enforcement advocacy boards are recommending that officers perform field sobriety tests like having the driver stand on one foot or checking for bloodshot eyes. However, a more comprehensive list of field sobriety tests would have to be compiled in order to truly measure whether or not a driver is impaired.

Marijuana and Car Accidents

A study by the National Highway Traffic Safety Administration found there is no large crash risk associated with drivers who had THC in their system, but it was noted that the subject needed more study. Alcohol, on the other hand, continues to be the largest crash risk at hand, contributing to one-third of all traffic deaths and requiring impaired driving injury lawyers to constantly be at work on one case or another dealing with an alcohol-related accident.

Accumulated contrasting information was revealed after cannabis was legalized in the state of Washington. Fatal car crashes involving drivers who had recently used marijuana jumped from eight percent to seventeen percent in the year that it was legalized. However, the drivers involved in the statistics usually also had alcohol in their system, as well as other drugs in some cases. Some of those who had tetrahydrocannabinol in their system were not impaired or at fault in the crashes.

Drugged Driving: A Growing Problem

According to the National Institute on Drug Abuse, driving after the use of marijuana can cause a number of problems. Marijuana-impaired driving can increase the potential of lane weaving, a dangerous activity that is responsible for many crashes. THC can also slow reaction time, causing the driver to hit the brakes too late in a situation where they need to stop behind another car or slow down for a red light. Recent marijuana users may have decreased coordination while driving, leaving them unable to perform basic maneuvers to the best of their ability. THC can also impair the judgment of time and distance, as well as alter attention to the road. Mixing alcohol with marijuana worsens all of the above symptoms.

The National Survey on Drug Use and Health claimed that ten million people had driven under the influence of illegal drugs within the last year. The same study showed that men were more likely than women to drive under the influence of alcohol and drugs, and young adults drive impaired at a higher percentage than older adults.

Handling an Accident Caused by THC-Impaired Driving

Driving while marijuana-impaired is still illegal in Illinois who has some of the nation’s strictest laws on driving under the influence. Throughout Illinois, an individual can be criminally charged with driving under the influence if a measurable amount of marijuana is found in their system. Even individuals who are medically prescribed cannabis are prohibited from operating a motor vehicle while under its influence.