The best thing to do is to call local authorities and they will pick up the cat. Agree there's no point taking a dead cat in your car. I think though when the cat is alive, that would be human decency as it could still be saved.
Though there are some mental people on my local FB group too. There is a 50mph road where cats sometimes get run over and some people post "something must be done about these maniacs driving"
yeah it's definitely the drivers fault that cats run out on the road without warning and definitely a great idea to break harshly on a busy road to avoid it lol. people should just not let their cats out or cat proof their gardens and let them out there if they care so much. I don't let mine out for that reason- bound to be run over basically