In 2007, there were 182,479 injury-related deaths in the United States—including homicides, suicides, and unintentional injuries—making injuries the leading cause of death for persons under age 45. Also in 2007, nearly 30 million Americans suffered a nonfatal injury serious enough to warrant hospital treatment. The lifetime cost of fatal and nonfatal injuries occurring in 2000 is estimated to exceed $400 billion. Efforts to prevent injuries have often focused on changes to the built environment or potentially dangerous products to reduce risks. Building safety into a product or environment—especially in ways that require little or no user action to confer protection—is often more effective than trying to change consumer behavior. For example, improving the crashworthiness of cars through design changes such as air bags, fire-resistant fuel systems, or electronic stability programs, is more effective than simply trying to teach operators to become safer drivers.