Add surviving a crash to the benefits of carpooling.
A passenger added to a vehicle's front seat reduces a driver's frontal crash fatality risk by 7.5 percent but increases the risk to the driver of the other car by 8.1. If the cars differ in mass by more than a passenger's mass, adding a passenger to the lighter car reduces total risk, according to the American Public Health Association.
The study used the Fatality Analysis Reporting System data to estimate how adding mass in the form of a passenger to a car crashing head-on into another car affects the fatality risks of both drivers.
The author concludes that "the finding that all cars carrying extra cargo generates a safer traffic system is clearly a technical finding and not a policy recommendation."