Unless you're in a no-fault state. In Michigan (And other no-fault states), most auto insurances are co-ordinated policies, which means you bill the health insurance and the auto picks up deductibles, copays and non-covered services. Medicare/Medicaid are never billed first, even in no-fault states..

Autos also sometimes require patients to stay within their health insurances network and obtain referrals, if it's an HMO.

I'll refrain from answering for states who don't have no-fault, I have no experience there.

Becki