Oh dear now that is very tricky. All parents worry about their children, but in your case it does seem rather extreme.
I suppose you will have spoken to them about this and how it makes you feel.
Maybe now is a good time to change the situation though. If you want to go to uni, decide which course you want to do and where you want to go. Then present it to them, say that you feel strongly that this would be the best thing for you to do and that although you are aware of their feelings on the subject (that they want you to go to your local uni) you think you have a good argument for going to [the uni of your choice].
In my experience, my parents were not happy with my choice of course at all (Law with Music Technology) and this is what I did and they reluctantly agreed I could g to Keele to do it. However, they were kind of right. I hated the Music Tech and switched to English at the end of the 1st year. But it was my choice, I wanted to do it and I learned from my own mistake.
Of course, it could be that your parents stand their ground and refuse to let you go where you want. In this case maybe more preparation is required. After you finish college, you could get a job and start saving, move into your own house/flat if possible (probably renting, maybe with some friends if possible) and do it on your own. It will show your parents you are responsible and able to cope on your own. If you can afford it, you could put yourself through uni of if you are living 'independantly' from your parents for about 3 years (can anyone confirm the length of time required?) you can apply for a student loan with no means testing of your parents, simply of yourself, which in most cases will mean you get help with uni funding anyway.
Of course it is a lot of work and you need to show your parents that you are responsible and you know what you want. Good Luck.