Catalytic converters were mandated by law in the 70's. So if we include the time period of the article mentions the beginning year of 1980 in the comparison of

Catalytic converters were mandated by law in the 70's. So if we include the time period of the article mentions the beginning year of 1980 in the comparison of weight, by that time most cars were automatic transmissions and included air conditioning. Plus the mid-priced to upper priced vehicles did include these extra amenities such as sunroofs, power windows, power seats and so forth. If you go all the way back into the 60s this wasn't the case but the article didn't go back that far it's specifically mentioned weight differences from 1980 until essentially modern times. And if you look at cars between those time periods primarily it was safety features airbags which have a significant amount of weight added along with abs traction control and even things like crumple zones add to the weight of cars. These were all things that had come about since the I'm very late 70s and early 80s. Even things like electronic fuel injection systems were common on American built cars by the early '80s. They have become refined over time, but those refinements have allowed them to become a more efficient and lighter in weight yet overall cars have increased massively. And this weight increase is despite lighter weight composite materials and the use of aluminum in many components that were not before. In the mid '80s old engines were essentially cast iron, now it's difficult to find an engine that is not aluminum. Even in heavy duty trucks the block may be cast iron still for durability but the heads are aluminum. You mentioned exhaust systems previously exhaust was exclusively steel, now it's common that it's a titanium based alloy that is very much lighter than the steel counterparts. I think we very much underestimate the weight of components such as airbags and abs systems have in cars.