People are weak for needing cars.

I think the reason that deer seem "retarded" in their response to cars is that for their entire evolutionary history there has never been an animal that would hurtle through both the day and night at improbable speeds almost completely silently. No land predator has previously evolved to blind its prey with large powerful sets of lights at night.

Counterintuitively, in my opinion deer seem to so often chaotically run out in front of cars (and growing up somewhere with lots of deer I know how incredibly infuriating and scary this can be) because it is actually the most sensible survival strategy for being ambushed by a fast moving predator with a lot of inertia that may or may not realize they have stumbled upon a meal.

Imagine you weren't a pathetic, slow human being and could outrun most predators, now imagine chilling inside a bush when you see a a grizzly bear sprinting at 40mph almmmossst but not quite straight at you.

Your impulse is to freeze and then wait for the right moment to bolt, especially because the predator hasn't seen you yet and likely just caught your scent or is running at something else. However, this predator is scentless, nearly silent and at night blinds you so that the distance they are away from you is very difficult to determine (the opposite of a grizzly bear really), so the right moment to bolt is hard to judge.

At the last second you realize the "grizzly bear" is almost upon you and you panic because it is happening so fast and fall back on your instincts. Your instincts, as a prey animal that can run faster and for longer than predators, are the same as any human who has ever played a sport where they need to rush past a defender.... and you erratically cut across the bear's path of motion after you think it has committed to rushing directly at you. The idea is to hopefully catch the bear with its weight shift committed in the wrong direction so you get just a tinnyyyy bit more of a head start in the chase. In otherwords the deer's instinct is to try to "juke" the fast moving predator with fancy footwork.

Please see the scientific illustration I have provided, notice that the bear's path (red) has to switch directions whereas if the deer had decided to just directly run away from their bear the bear wouldn't have needed to switch directions/accelerate twice, just make a slight turn to reorient itself into an opportunistic chase with the deer.

This doesn't work on cars, especially because if at first a deer doesn't succeed at getting the timing right they are dead.

You're completely right. Many other animals understand the concept of roads and will leave them when a car approaches, as long as you don't surprise them before they have the chance. Foxes for example.

Deers however will cross a road when a car approaches, and sometimes even change their mind and cross the road a second time in the other direction.

But deer are a pest in most areas anyways, so they are better off dead. Just a shame for the damage done to the car