I had the same question and thanks to Freeper Tax-chick, I learned that if you are the driver at fault (and the mother was the only driver involved in the accident), your auto insurance will not cover medical expenses.
And I learned from another FReeper that, in Maryland, you have to have a Personal Injury Protection (PIP) on your policy, which pays (he said) about $2,500 regardless of fault.
I wonder who paid the mother’s medical bills ... or if she was wearing her seat belt, and therefore didn’t have significant injuries.