Medical Marijuana Laws, Traffic Fatalities, and Alcohol Consumption
研究了美国19个州医用大麻合法化对交通事故死亡的影响，发现合法化后第一年交通事故死亡减少8-11%，且酒精相关事故死亡下降更明显，表明大麻与酒精可能互为替代品。
To date, 19 states have passed medical marijuana laws, yet very little is known about their effects. The current study examines the relationship between the legalization of medical marijuana and traffic fatalities, the leading cause of death among Americans ages 5-34. The first full year after coming into effect, legalization is associated with an 8-11 percent decrease in traffic fatalities. The impact of legalization on traffic fatalities involving alcohol is larger and estimated with more precision than its impact on traffic fatalities that do not involve alcohol. Legalization is also associated with sharp decreases in the price of marijuana and alcohol consumption, which suggests that marijuana and alcohol are substitutes. Because alternative mechanisms cannot be ruled out, the negative relationship between legalization and alcohol-related traffic fatalities does not necessarily imply that driving under the influence of marijuana is safer than driving under the influence of alcohol.