I think manufacturers should just fit something to cars so police can turn them off with a remote control in the event they fail to stop 
You'll love that when someone
other than the police turns it off! And don't say "It'll be secure" because, well.. have you looked at the Internet lately?

Actually the technology already exists, I believe, in current OnStar vehicles, and has already been compromised. Ah, yes:
https://www.wired.com/2015/09/gm-took-5-years-fix-full-takeover-hack-millions-onstar-cars/For the short of attention span: GM took 5 years to stop a criminal being able to remotely activate the brakes & transmission and, y'know, potentially kill you.
The technology must be there to do that James, but some lawyer will come along to bleat about civil liberties etc.
That and it'll take scrotes about a week to figure out how it's done and then start doing it for sh!ts and giggles. 
See above

I particularly like the fact that the researchers followed
responsible disclosure (full disclosure: this stuff is my job) and GM effectively ignored them until someone went public, four years later. Of course, it's possible that GM were
told to ignore it by, say, the US intelligence service, because you'd never see the NSA sitting on unpublished 0-days for.. oh, wait, you do.