I have found that the tighter that hold gets, the more the child will run away from you: not answering calls, making up stories, flat-out lying, and while away from you-taking more risks in order to rebel against the "my way or the highway" mentality at home.
Do parents really want to be dictators? Why can't it be a democracy? Parent out of your hopes, NOT you fears! You will not always be there for your child. Have you allowed them to think for themselves? Thinking for yourself and practicing making decisions is the ONLY way to get good at it!
I have found that one of the biggest mistakes we make as parents is to not have a relationship of respect and trust with our children. It doesn't have to be a line in the sand with total submission. It can be a collaboration; this promotes trust and an environment of MUTUAL respect. I have found that as a parent you cannot DEMAND respect: if this is tried, it can backfire and cause resentment.
IMO: you need to sit down with your daughter and have a mature, adult conversation. Tell her that you want to trust her to make good decisions and that you will do your best to allow her to make her own choices. But, with that freedom comes responsibility. It is imperative to have a positive relationship in which all parties involved respect one another: and that means calling and letting others know where you are, who you are with, and approximately when you will be home.
At 18, I thought that I knew a lot. I realize now that life is much more complex and difficult that I had ever realized and I am thankful that I had a great relationship with my mother, who was and is my best friend, to talk to, to confide in, and whom I could respect. She was ALWAYS respectful to me. ALWAYS. She trusted me. I had a lot of freedom, but I never blew it because I knew how hard it is to gain.
I once was on the phone with a guy friend late at night. He wanted me to sneak out and come hang out at his party. I told him that if I had wanted to come, I would walk right out the front door. The point is: I DIDN'T NEED TO SNEAK OUT! I knew that my mom would be reasonable if I wanted to go, I didn't have to go behind her back to get my way. There were never any power struggles or battles of wills.
Don't make her social life, parties, friends, boys, events, etc the forbidden fruit: she'll just want it that much more and she will do riskier things to get it.
It's all about respect. Examine your relationsihp and find out what it will take so that all parties give one another the utmost respect and treat one another like responsible human beings.
One more thing: I don't want my 18 year old daughter moving out on her own. I don't think at that age she is equipped to fly completely solo. She's getting there, but I don't want her to make decisions out of desperation. I want her to know that I will support her (different than enable) and help if she should need it. It's about empowerment. Help her realize her full potential. Don't get bogged down by the insignificant details.
Just MO