I’d like to know the halachic provisions regarding involuntary, unintentional touch between a non-married Jewish woman and a non-married Jewish man. Obviously, touching is forbidden if it does not take place within the context of marriage, but I am asking within the context that the touch is involuntary and what should be done in this case?

Shalom U'verachah, One should take all precautions not to be in a situation that they would come to touch others of the opposite gender. However, in a case where this touch is unavoidable, such as public transport, and is occasional, ie. is not continual touching, but a truly accidental brushing past another person, then it would be allowed to go to such a place. Kol Tuv