2. Crumple Zones An engineer at Mercedes, came up with a safety concept that would completely change how cars were designed and built. Prior to 1959, people believed the stronger the structure, the safer the car. But in actuality, such construction proved deadly to passengers, because the force from impact went straight inside the vehicle and onto the passenger. In the end, he designed two "crumple zones" -- one in the front of a car and one in the back. Crumple zones relied on a skeletal frame of special materials that would crumple in predictable ways, absorbing the energy of a collision.

3. Seat Belts The seat belt was introduced in 1949 by Nash Motors, but it was not until the mid-1950s that most automakers began offering seat belts as optional safety features. These safety belts crossed over a passenger's lap, securing him or her to the seat in order to prevent a collision with the dashboard, steering wheel, or windshield in an accident. While the seat belt vastly improved a passenger's safety, it remained far from perfect, and nasty head, spinal, and other injuries continued to occur.

4. A seatbelt on a roller coaster The simplest sort of seatbelt, found in some roller coasters, consists of a length of webbing bolted to the body of the vehicle. These belts hold you tightly against the seat at all times, which is very safe but not particularly comfortable.

5. Air Bags Through a series of cras tests, engineers and safety experts determined what was needed to make the airbag a successful safety feature. Hetrick's airbag concept was seen by many as the ultimate passive restraint, even though manufacturing safe airbags would clearly be an enormous challenge Engineers had to determine how big the bag should be, what materials should be used in it, and how to inflate it within 30 milliseconds after impact without blowing it apart. These challenges were met, however, and by 1980, Mercedes began offering airbags as standard equipment. Eight years later, all U.S. car manufacturers were required to follow suit.