One example I've read about is that increased fuel economy requirements actually had a reverse effect in the case of the Ford Ranger. This is because the regul

One example I've read about is that increased fuel economy requirements actually had a reverse effect in the case of the Ford Ranger. This is because the regulation was based on vehicle footprint, and in order to get the Ranger to meet the regulation it would have priced it higher than the more capable F150. So the Ranger (which got around 22 MPG) was discontinued (along with most similar sized pickup trucks), and those customers bought the F150's that got 15 MPG. BTW, someone pointed out previously that there is more to the story than just fuel regulations that killed the Ranger and similar vehicles, so take the above with a grain of salt if needed.