I have to agree with BP's question of whether your son is hiding something by not getting the urine test.

I am rather disturbed by the way he reacts toward you and your VERY REASONABLE demands. Yes, I wanted to make sure that you knew that what you are requiring of him is absolutly reasonable. I think that there are two possiblities. Either he is playing you for a sucker or he has some sort of mental illness that needs to be treated. The urinephobia. The refusing to get out of the car. And the fact that you are afraid you are going to have to have the police help you get him out of the house. These things are sending up a hundred red flags at the back of my head. I think before you do anything you might want to go see a therapist to get a handle on what is happening with your son. When I had my break down my husband went and saw a therapist just so he could have a qualified professional help him understand what was happening to me. A therapist would be able to sort out what is happening and give you some real life solutions.
Take care,
Zen

<font color=blue>I was always looking outside myself for strength and confidence but, it comes from within. It is there alll the time.--Anna Freud