The association between legalization of cannabis use and traffic deaths in Uruguay

Abstract

Background and aims While cannabis use has been found to impair motor vehicle driving, the association between cannabis legalization and motor vehicle fatalities is unclear. In Uruguay in December 2013, cannabis for recreational purposes was legalized. This study assessed the association between implementation of this law and changes in traffic fatality rates. Design Interrupted time–series analysis of traffic fatality rates of light motor vehicle drivers and motorcyclists in urban and rural settings. Changes are reported as step and trend effects against modeled trends in the absence of legalization. Setting Uruguay, Montevideo and four rural provinces (Colonia, Florida, Río Negro and San José) from 1 January 2012 to 31 December 2017. Cases and measurement Weekly traffic fatalities of light motor vehicle drivers and motorcyclists per type of vehicle. Data were gathered from the National Road Safety Agency of Uruguay and the Ministry of Transport and Public Works, respectively. Results Cannabis legalization was associated with a 52.4% immediate increase [95% confidence interval (CI) = 11.6, 93.3, P = 0.012] in the light motor vehicle driver's fatality rate. However, no significant change in the motorcyclists’ fatality rate was observed. In Montevideo the legislation was associated with an absolute increase in its light motor vehicle driver's fatality rate by 0.06 (95% CI = 0.01, 0.11, P = 0.025), but no significant associations were observed in rural settings. Conclusions In Uruguay, the 2013 legislation legalizing recreational cannabis consumption may have been associated with an increase in fatal motor vehicle crashes, particularly in light motor‐vehicle drivers and urban settings.

Cannabis legalization and traffic injuries: exploring the role of supply mechanisms

“…Despite these limitations, the robust finding on self‐cultivation is not only generally consistent with an earlier study (which largely focused on the period before pharmacies started selling) [6], it also raises questions that may be of interest outside of Uruguay. Although our data preclude us from assessing the factors underlying this association, we wonder if the differential potencies of cannabis flower associated with different supply mechanisms may help explain the results.…”

“…Outside the United States, we are only aware of one study examining the relationship between nonmedical legalization and traffic safety. Focusing on five jurisdictions in Uruguay and using an interrupted times series approach focused on when the law was enacted in December 2013, the study finds that enactment 'may have been associated with an increase in fatal motor vehicle crashes …' [6] Our article contributes to this literature by looking beyond enactment in Uruguay and using a novel dataset that reports the number of people in Uruguay who registered with the government to obtain legal cannabis through one of three supply mechanisms: (i) self-cultivation ("growers"); (ii) becoming a member of a non-profit cannabis club and paying a monthly fee that in some instances would be offset by in kind labour ("members") [7]; or (iii) purchasing at a pharmacy ("purchasers"). We examine how variation in registrations for legal cannabis-in total and by mechanism-is associated with traffic crashes involving injuries.…”

“…Outside the United States, we are only aware of one study examining the relationship between nonmedical legalization and traffic safety. Focusing on five jurisdictions in Uruguay and using an interrupted times series approach focused on when the law was enacted in December 2013, the study finds that enactment ‘may have been associated with an increase in fatal motor vehicle crashes …’ [6]…”

An overview of select cannabis use and supply indicators pre- and post-legalization in Canada

“…There do not appear to be increases in treatment admissions for cannabis use disorders and data on changes in cannabis-related traffic fatalities are mixed [7][8][9][10]. Mixed results for key outcomes have been observed for Uruguay as well [11][12][13].…”

From “Bhang Shops” to “Cannabis in Coffee Shops”: Time to Debate the Option?

“…However, an increase in fatal motor vehicle accidents was noticed since 2013. 29 Spain allows for cannabis clubs. These clubs have been established since 2002, following a series of Spanish Supreme Court rulings.…”