A policy that reduced workweeks for medical residents hasn't helped junior doctors get more sleep, and it hasn't kept them from making mistakes or getting into car accidents, a new study shows. In the past, residents sometimes worked 36 hours straight and worked 100 hours a week. But a 2003 policy from the Accreditation Council for Graduate Medical Education cut shifts back to 24 to 30 hours, with a maximum of 80 hours per week. Doctors hoped that cutting back hours would prevent exhausted residents from making life-threatening medical errors and keep sleepy doctors from falling asleep at the wheel. A study of 220 residents, however, shows little change.