Hmmmm….those girls who are worried about wearing a seat belt and accentuating her assets should sit in the back seat preferably with a sheet over her head (for modesty reasons).
I once went on a date and the boy told me that for tznius reasons he does not open the door for women. While I respected his way of doing things, I knew that this was not the way I was raised, and the boy was not for me for other reasons in the end. My husband opened the door for me when we were dating and he still does (Bli ayin horah).
Oh…and I also feel that it is not tznius to compliment the girl on her clothing, unless you are engaged. Not a psak, but just my opinion.