Traffic safety and automobile safety are a major component of injury prevention because it is the leading cause of death for children and young adults into their mid 30s. Injury prevention efforts began in the early 1960s when activist Ralph Nader, exposed the automobiles as being more dangerous than necessary with his book Unsafe at Any Speed. This led to engineering changes in the way cars are designed to allow for more crush space between the vehicle and the occupant. The Centers for Disease Control and Prevention (CDC) also contributes much to automobile safety. The CDC Injury Prevention Champion, David Sleet, illustrated the importance of lowering the legal blood alcohol content limit to 0.08 percent for drivers; requiring disposable lighters to be child resistant; and using evidence to demonstrate the dangers of airbags to young children riding in the front seat of vehicles.