- In 1975, the Federal Corporate Average Fuel Economy (CAFE) standard was ratified. It meant auto manufacturers had to follow particular mileage standards for their complete car line-up.

- Thus, starting in 1976, each vehicle’s average steel content was reduced from 1035 kg to 795 kg. (That’s roughly 20%, right? Any Math major out there cares to challenge me? ;P)

So how did they do this?

(1) Decreasing the size of the vehicle

(2) Changing the lay-out from Body-on-Frame to Unibody

(3) Researching on light materials

The practice went on until 1982.