1973
Fuel efficiency
Despite growth in oil and gas prices, Americans believed that Middle Eastern oil exporters couldn’t afford to lose lucrative business from the US. That belief changed in 1973 with an oil embargo that led to fuel shortages, rationing, and an energy-saving national speed limit of 55 MPH.
Car sales dropped by over 20%. Muscle cars disappeared. Car manufacturers began to think smaller and lighter, using more aluminum and plastic.