THC is the most prevalent illicit drug found in drivers who have been involved in car crashes, including fatal crashes.  

The effects of cannabis use include a lack of attention, slower reaction time, difficulty making decisions, impaired coordination.   

Data show that the risk of being in a motor vehicle accident doubles after smoking cannabis. 

It could take 3 to 4 hours for it to be safe to drive if you have inhaled marijuana.  The margin is longer if you have consumed edibles based on the amount ingested and the THC level.  

TIP: Plan ahead to avoid the need to drive.  If you need to go somewhere call a taxi or have a sober friend do the driving.  

Help is available 

• Health Promotion and Wellness offers free alcohol and cannabis education services for students who do not have a violation.  
• ScreenU is set of free and anonymous online screening tools for alcohol, marijuana and prescription drugs.  The screening tools are available to all Penn State students. 
• Collegiate Recovery Community provides support to Penn State students who are in recovery from alcohol and other substance use disorders.  
• Counseling and Psychological Services offers individual and group counseling services as well as a variety of self-help resources.  

Sources:  

Addictions, Drug & Alcohol Institute, University of Washington, Learn about marijuana. 2020 

Centers for Disease Control and Prevention, What you need to know about marijuana use and driving.  April 13, 2017. 

Lacey, J, Kelley-Baker, T., Berning, A., Romano, E., Rameriez, A., Yao, J….& Compton, R. (2016). Drug and alcohol crash risk study:  A case-control study (Report No. DOT HS 812 255). Washington, DC:  National Highway Traffic Safety Administration. 

Hartman & Huestis (2013). Cannabis effects on driving skills, Clin Chem 2013. Mar: 59(3): 478-92.