Crack cocaine markets were associated with substantial increases in violence in the U.S. during the 1980s and 1990s. Using cross-city variation in the emergence of these markets, we show that the resulting violence has important long-term implications for understanding current levels of murder...

Teens are risky drivers and often subject to extra restrictions. We examine the effects of an Australian intervention banning first-year drivers from carrying multiple passengers between 11:00pm and 4:59am, which had represented 3% of their accidents and 18% of their fatalities. Using daytime...