Combining alcohol consumption with marijuana can increase the chances of a fatal vehicle crash nearly five-fold when compared to drivers who used neither substance. In a study published in the journal Annals of Epidemiology, researchers at Columbia University Mailman School of Public Health, determined that drivers who caused fatal crashes were much more likely than blameless drivers to test positive for alcohol, marijuana, or both substances. You can read more about this study here: https://medlineplus.gov/news/fullstory_166626.html.
Aylesbury Press publishes Medical Cannabis: What Clinicians Need to Know and Why by Gregory Smith, MD, MPH. Copies can be ordered at www.aylesburypress.com.