The author tells us that one way people are suggesting improving efficiency is to make cars smaller, but since this makes them less safe, we should not improve efficiency.
There is a big issue here. The safety argument is a strong retort against making cars smaller, but not against improving efficiency. The author gives us no reason to reject the goal of efficiency, only to reject one way of achieving that goal, making cars smaller. There could be other ways of achieving it without making cars smaller.
