The Dangers of Driving High

On behalf of Gordon Law Offices, Ltd.   |  Feb 05, 2021   |  Car Accidents
Drunk man driving while holding a bottle of alcohol

Studies have shown marijuana to impair the cognitive skills required for safe driving, including motor coordination, attention, tracking, and visual function. The risk of being involved in an accident significantly increases after marijuana use.

Impaired Driving Skills

People become impaired when they are high. Like drunk drivers, they start taking more risks. Studies have linked marijuana to increased lane weaving.

Marijuana, like alcohol, affects the skills that a driver requires to drive safely. It affects cognitive functions and psychomotor skills. It can affect a person’s ability to make decisions and delay reaction times. Marijuana use can also distort perception, impair coordination, make problem-solving more difficult, and cause memory loss. 

Increased Crash Risk

Car accident lawyers are handling more cases involving drivers under the influence of marijuana. Reviews of multiple studies have found the risk for car accidents increased significantly after marijuana use. In some studies, the risk more than doubled.


THC (tetrahydrocannabinol) is marijuana’s active ingredient. It affects parts of the brain that control body movements, coordination, balance, judgment, and memory. In car accidents, drivers who have THC in their blood – especially high levels – are more likely to be responsible for the accidents. That is in comparison to drivers who had not used alcohol and drugs.

In Chicago, drivers with at least 5 nanograms of THC per millimeter of blood can be charged with drugged driving. A blood test can detect THC 3 to 4 hours after marijuana use. Driving under the influence of drugs is illegal in Illinois. Therefore, driving while high can have considerable legal consequences.

Fatal Crashes

Studies have shown people with THC in their blood were twice as likely to be liable for deadly crashes than drivers who had not used alcohol or drugs. According to the Drug-Impaired Driving survey by the Governors Highway Safety Association (GHSA), 43.6% of the drivers in fatal accidents tested positive for drugs.

Drugs and Alcohol

According to the GHSA, the last 10 years have seen a 16% increase in the number of fatally injured drivers who were alcohol-impaired and had drugs in their system. Using alcohol together with marijuana amplifies the effects of both. That results in an even greater risk for car crashes than when either drug is used by itself.

It is safest for people to drive when they do not have any drugs or alcohol in their system.