According to How we Die, 35 percent of trauma in the United States is caused by automobiles and 7 percent by motorcycles. (10% of trauma is from gunshots and another 10% is from stabbings. Pedestrians suffer 7-8% of the major injuries, and 17% occurs as the result of falls. The other 15% is from industrial accidents, bike accidents, and suicide injuries.)
Every year, roughly 1.3 million people die in car accidents worldwide – an average of 3,287 deaths per day. Young adults aged 15-44 account for more than half of all road traffic deaths. Globally, car accidents are the leading cause of death among young adults ages 15-29 – and the 9th leading cause of death for all people.
In 2019, 38,800 people were killed in car accidents in the United States – down two percent from 2018 (39,404 deaths). In 2017, 40,327 people killed in U.S. motor vehicle collisions. In 2016, there were 34,439 police-reported fatal car accidents – a 5.8 percent increase from 2015. In 2010, the cost of medical care and productivity losses due to injuries from car accidents was more than $99 billion – nearly $500 for each licensed US driver. More stats here.
The cause of automobile accidents varies, of course, with everything from recklessness to fatigue being a factor. However, the single largest factor is alcohol, playing a role in about half of motor vehicle deaths in the United States.
Deaths from trauma are described as trimodal, that is they are either immediate, early or late. Half of all deaths occur immediately (within a few minutes) as a result of injury to a major blood vessel, the heart or the central nervous system (brain damage and bleeding are each responsible for a third of trauma deaths). Others occur within a few hours as a result of harm to the head, lung, or abdomen or bleeding within. Late death occurs days or weeks after the injury, often from complication of infection or lung, kidney or liver failure.