Last week I noted the Trump administration's professed concern that higher mileage standards would lead to more traffic deaths because fuel efficient cars make it cheaper to drive, therefore people will drive more. As I pointed out at the time, if Trump wants to discourage people from driving then shifting to pay by the mile insurance policies would have create much more disincentive than having them drive fuel inefficient cars.
I gave some links to the relevent literature in that blog post, but here are some newer ones.
I'm sure the Trump administration will soon be leading the charge on this issue.
Thanks to Mark Brucker for the references.