Trends in fatal motor vehicle crashes before and after marijuana commercialization in Colorado.
BACKGROUND
Legal medical marijuana has been commercially available on a widespread basis in Colorado since mid-2009; however, there is a dearth of information about the impact of marijuana commercialization on impaired driving. This study examined if the proportions of drivers in a fatal motor vehicle crash who were marijuana-positive and alcohol-impaired, respectively, have changed in Colorado before and after mid-2009 and then compared changes in Colorado with 34 non-medical marijuana states (NMMS).


METHODS
Thirty-six 6-month intervals (1994-2011) from the Fatality Analysis Reporting System were used to examine temporal changes in the proportions of drivers in a fatal motor vehicle crash who were alcohol-impaired (≥0.08 g/dl) and marijuana-positive, respectively. The pre-commercial marijuana time period in Colorado was defined as 1994-June 2009 while July 2009-2011 represented the post-commercialization period.


RESULTS
In Colorado, since mid-2009 when medical marijuana became commercially available and prevalent, the trend became positive in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive (change in trend, 2.16 (0.45), p<0.0001); in contrast, no significant changes were seen in NMMS. For both Colorado and NMMS, no significant changes were seen in the proportion of drivers in a fatal motor vehicle crash who were alcohol-impaired.


CONCLUSIONS
Prevention efforts and policy changes in Colorado are needed to address this concerning trend in marijuana-positive drivers. In addition, education on the risks of marijuana-positive driving needs to be implemented.
Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States. Electronic address: stacy.sautel@gmail.com.
Stacy
S
Salomonsen-Sautel
Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States.
Sung-Joon
SJ
Min
Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States.
Joseph T
JT
Sakai
Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States; Denver Health and Hospital Authority, Denver, CO 80204, United States.
Christian
C
Thurstone
Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States.
Christian
C
Hopfer
D000063:Accidents, Traffic / Q000401:mortality* / Q000639:trends*; D000428:Alcohol Drinking / Q000453:epidemiology; D002188:Cannabis; D003120:Colorado / Q000453:epidemiology; D006801:Humans; D007880:Legislation, Drug / Q000639:trends*; D008385:Marijuana Smoking / Q000453:epidemiology; D064086:Medical Marijuana; D015995:Prevalence
D064086:Medical Marijuana
Alcohol-impaired driving; Drugged driving; Marijuana-positive driving; Medical marijuana; Traffic fatalities