RESEARCH

ABSTRACT

A heavy truck imposes an externality if its presence causes traffic accidents for which it is not held liable. We estimate the increase in accidents that occur when a truck is added to a road using quasi-experimental variation in truck routes of connecting shale gas wells in Pennsylvania. We find evidence that adding a truck to a road is relatively safe for the truck itself, but less so for other cars on the road: an additional truck leads to an increase in the number of car-only accidents. However, these additional accidents are not more severe. Finally, we find suggestive evidence that the accident externality of trucking reverberates to even more road users through higher car insurance premiums.