You don't have to answer all posts - you would be driven demented very quickly that way! - but you do need to acknowledge that you have been given positive advice here.
And you have been guilty of what is called 'AIBU by stealth' by not revealing all the pertinent information in your OP (original post)
Your child is an adult, as she is 18. You shouldn't be trying to pick her up from her social events anyway, as she does have to develop her own independence. That said, I do understand that you would worry about her safety. My DS1 is 18, and I worry about him coming home if I know he will be travelling alone - which is why I suggested a taxi account. Yes, it's not going to be cheap, but it's better that than worrying about her walking home on her own.
We're lucky where we live as we have a good bus network, or access to the tube, but it's not always so easy.
If you can't afford a taxi, then you need to work out with your DD how she is going to get home after an evening out. Perhaps she could stay over with a friend if the only alternative is coming home on her own?
But the point is, she is no longer a child. To insist that she is in by 11 will only serve to alienate her. Work together to find a way that will satisfy both of you.
This also includes establishing the ground rules - e.g. if it's a school night, then she can't be out after a certain time, whereas at the weekend it can be different.