They dont have to read you your rights if they are not going to interogate you for anything. Trust me I know that one for a fact. Second i dont understand how he could get you for going 15 in a 35 i mean if your speeding then in my area that means your doing more then 5mph over the speed limit. Third it must be more to the story cus I dont see how if u had all ur proper paper work that they would arrest you and then tow your car. I've been caught without no paper works and aint get nothing but a $55 speeding ticket ( i guess cus it was a cool cop). When i got locked up i never got my phone call neither but that didnt really mean nothing. What you should look into is seeing if u can get that thing ( i forgot what its called) for first offenders. That is if this is your first offence. Fifth thing is, what does your friends insurance got to do with your car. I think we need more info about what actually went down.