Although the causal relationship between cannabis laws and CU problems is intrinsically difficult to determine, various reports suggest a pattern of growing CU problems. CU may impair motor coordination and driving skills, thereby increasing the risk of injuries (Institute for Behavior and Health, 2013; Volkow et al., 2014). Acute cannabis intoxication may increase motor vehicle crash risk (Rogeberg and Elvik, 2016). Brady and Li (2014) found a significant increase in the trend of cannabis-detected fatal injuries during 1999–2010, whereas the prevalence of alcohol-detected injuries remained stable. Additionally, medical cannabis laws were associated with a 10–20% increase in cannabis arrests and CU-related treatments, suggesting a possible legalization effect on CU problems (Chu, 2014). The total physical availability of medical cannabis through dispensaries and delivery services at the city-level also was positively associated with current CU and frequent use (Freisthler and Gruenewald, 2014). Cities with comparatively high levels of medical cannabis availability showed a frequent CU pattern. Likewise, Mair et al., (2015) found that the density of local cannabis dispensaries was positively associated with an increase in CU-related hospitalizations. Moreover, cannabis potency
