What are my rights if a roommate took my car without permission and crashed it?

Your roommate has to check if the insurance goes with just his car or covers him when he is using someone else's car. If he stole your car, he is guilty of a felony. If you had uninsured motorist coverage you might be able that your insurance applies because he was uninsured for the crash, but I assume you did not buy that coverage. Get him to sign a document stating precisely how much he owes you and is to pay you per month, plus interest, and that if he misses more than one payment he agrees to stipulate to the debt if you sue him [judgment last 10 years and can be renewed indefinitely, but you have to find him to collect].