Unlike the others, this one I don't think is very well reasoned.

Because the case here is that the unborn child is a person, the car accident analogy is badly incomplete. Where is the person?

Instead, the analogy might go like this: Everyone knows that driving is risky. But when you're about to get into an accident where you'll get hurt and your car will be damaged and swerve, knowing full well that you'll strike and kill a pedestrian and therefore avoid the accident, nobody considers this murder or manslaughter.

Eeeeexcept we do tend to consider it at least manslaughter. Their right to life exceeds your right to not have a banged up car and some injuries.

You've only managed to make a case for pregnancy insurance here, not abortion.

Also, that "reasonable precautions do not include abstaining from sex" needs an argument. Simply stating it comes perilously close to begging the question, since the claim was that sex is a consent to gestate a child should that happen.

Finally, the argument rests on having taken reasonable precautions. If it is a different case when one hasn't taken precautions, how does anyone know that a woman wanting an abortion has or has not taken reasonable precautions? It seems peculiar that this would be of critical moral relevance, but if it is, this is a serious practical concern. If it isn't, an argument should not rely on it.

(Note--there is also a curious interplay between reasoning here and reasoning about how we should view rape: if you are not responsible for your own pregnancy when you choose to have sex, the rapist also cannot be held accountable for your pregnancy if he rapes you. He can be held accountable for other things, of course. (I'm aware there is more nuance to this, but I'm just jotting this down as an aside for now, not developing it fully, as it's not really on topic.))