He defined interactions between host (human), agent (motor vehicle), and environmental (highway) factors before, during, and after crashes resulting in injuries.
[citation needed] Tackling problems identified with each factor during each phase of the crash, NHSB initiated a campaign to prevent motor-vehicle-related injuries.
[13][14] State and local governments have enacted and enforced laws that affect motor-vehicle and highway safety, driver licensing and testing, vehicle inspections, and traffic regulations.
[7] Preventing motor-vehicle-related injuries has required collaboration among many professional disciplines (such as biomechanics has been essential to vehicle design and highway safety features).
Citizen and community-based advocacy groups have played important prevention roles in areas such as drinking and driving and child-occupant protection.
[12] Consistent with the public/ private partnerships that characterize motor-vehicle safety efforts, NHTSA sponsors "Buckle Up America" week, which focuses on the need to secure children in child-safety seats properly at all times.
[12][19] The prevalence of safety belt use after enactment of primary laws increased 1.5-4.3 times, and motor-vehicle-related fatality rates decreased 13%-46%.
[19] Child-safety and booster seats: All states had passed child passenger protection laws, but these varied widely in age and size requirements and the penalties imposed for noncompliance.