The presence of a heavy truck on the road can impose an externality if accidents occur that would not have otherwise. We find each additional truck on the road increases the risk of a truck accident – but also, at an even higher rate, the risk of a car-on-car collision. Our estimates imply two...

Each year, 10,000 individuals die in alcohol-impaired traffic accidents in the United States, while psychoactive drugs are involved in 20% of all fatal traffic accidents. We investigate whether state parity laws for substance use disorder (SUD) treatment have the unintended benefit of reducing...