The leading cause of death for Americans under the age of 46 is trauma — a disabling or life-threatening physical injury that results from an event such as a motor vehicle crash, gun violence, or fall. In 2013, trauma cost approximately $670 billion in medical care expenses and lost productivity. Recognizing that the best strategy to reduce the considerable burden associated with trauma is to prevent injuries from occurring in the first place, the delivery of optimal trauma care when injuries do occur is a critical means of preventing unnecessary death and disability. Of the 147,790 U.S. trauma deaths in 2014, as many as 20 percent — or about 30,000 — may have been preventable after injury with optimal trauma care, the committee said.