The question about placement and meaning of adjectives like dernier and prochain comes up a lot. Just for reference, here is the corresponding lesson: Dernier = final/previous (French Adjectives that change meaning according to position)
Le virage dernier -- the previous curve, i.e., the one you passed mosed recently (but there are more possibly more curves ahead)
Le dernier virage -- the last curve of a sequence, i.e., after this the road continues straight.
I have noticed, however, that the version with dernier preceding the noun is given preference. I often hear la dernière fois and rarely la fois dernière, even though the speaker clearly refers to the most recent time and not the last time. I suspect that this rule is not an absolute.