Resident physicians in the United States currently work no more than 80 hours per week, according to regulations passed in 2003. By contrast, pilots are governed by much stricter regulations that limit their duty hours to approximately 1400 flying hours per year. This cost evaluation found that applying aviation industry work hour regulations to resident physicians would increase costs by more than $6 billion per year. Although a recent Institute of Medicine report recommended reducing the maximum shift length and increasing the duration between shifts—at an estimated cost of $1.7 billion—no reduction in the maximum number of hours worked per week was proposed. However, resident physicians in Europe will soon be restricted to working 48 hours per week, and a recent study of such a system found improved safety.