The Marching Morons, a Fifties-era 1951 science fiction novel short story by Cyril M. Kornbluth, describes a future in which people of lower intelligence have continued to breed while the smart ones use birth control, with the result that the average intelligence of humanity is drastically reduced. The protagonist, a time traveler, is taken for a ride by an ordinary citizen in a flashy car that makes lots of noise and seems to be going quite fast, but he notes that it really doesn’t get anywhere very quickly.
Prof. Reynolds links to a NYT article: Hybrid Cars May Include Fake Vroom for Safety. Kornbluth would no doubt be delighted at the vindication of his prediction. I’m not totally sure the rest of us should be quite so pleased.