In countries with poor enforcement of road-safety standards, risky drivers endanger their passengers and those in other vehicles. In such an environment, reducing the costs that dangerous drivers impose on other road users is difficult. This paper evaluates an intervention that aims instead to reduce the costs a bad drivers impose on their own passengers, who face a collective-action problem when choosing whether to speak up when a driver compromises their safety. In the experiment, messages designed to lower the costs of speaking up were placed in a random sample of over 1,000 minibuses in Kenya. Analysis of comprehensive insurance data covering a two year period that spanned the intervention shows that insurance claims for treated vehicles decreased by one-half to two-thirds, compared with the control group. In addition, claims involving an injury or death decreased by at least 50 percent. Passenger and driver surveys indicate that passenger heckling contributed to this reduction in accidents
This paper was made possible in part by support from the Australian Agency for International Development.