I wish writers would stop with this analogy. The cars, as a percentage of the US fleet are NOT being taken off of the road. They are still on the road running at the same inefficient levels. Buses and mass transit, fuel embargoes, major catastrophe’s such as a
storm surge associated with a hurricane are the only things that take
cars off of the road, the latter only temporarily until people get their
insurance payout and buy a new vehicle which leads to the production of
another car to replace it on the lot.

A distinctly more relevant and apropos subject to compare this to would be taking a coal fire power-plant off line, or reducing the need for natural gas and the highly polluting drilling/fracking that goes along with it, reducing the need to mine for more uranium for the nuke industry, etc.