Does social capital matter? A study of hit-and-run in US counties

We investigate the relationship between social capital and a decision that has dire health consequences: fleeing after a road accident. This event is unplanned, and the decision is taken under great emotional distress and time pressure, thus providing a test of whether social capital matters for behaviour in extreme conditions. We merge data from the universe of fatality accidents involving pedestrians in the US over the period 2000-2018 with a dataset on social capital measures at the county level. Using within-state-year variation, our results show that one standard deviation increase in social capital is associated with a reduction in the probability of hit-and-run of around 10.5%. Several falsification tests based on differences in social capital endowment between the county where the accident occurs and the county where the driver resides are suggestive of a causal interpretation of this evidence. Our findings show the importance of social capital in a new context, suggesting a broad impact on pro-social behaviour and adding to the positive returns of promoting civic norms.