Some American work has a legal limit on hours. A truck driver carrying freight “may drive a maximum of 11 hours after 10 consecutive hours off duty.”
Hospital residents have a national limit of 80 hours a week, averaged over four weeks. It goes back to the death of Libby Zion, 18, at a New York hospital in 1984. New York set limits for residents in the late 1980s. In 2003 the national accrediting body for residency programs set the 80-hour limit for the whole country.
The resident limit grew out of concern for the safety of patients.