As long as the crosses don't have sayings, advertisements for Christianity, I have no problem with people putting crosses on roads where loved ones died. But...if you put a big sign on the cross that said something like, "repent to Jesus and you will be saved" then that would be using the public square to preach to me. There is a fine line between rememberance, and backdoor proselytizing. I can't think of any crosses on roads I have seen that said anything other than innocuous sayings like, "rest in peace, we will never forget you, you remain in our hearts" which is respectful and I would say you would have to be fairly heartless to want removed.

I would like to see the proof you speak of, because I seriously doubt that having a cross was the only reason for asking for their removal.