What is the ruling on saying to my father, "It is haram and by divorce I will not ride with you in this car," knowing that it is not his property?

You must consider your intention and purpose in saying "haram" to your wife. If you intended divorce, then it is a divorce. If you intended ẓihār, then it is ẓihār. If you intended an oath or did not intend anything, then you owe an expiation for an oath (kaffārat yamīn).

If you intended divorce, then two divorces are binding upon you, unless you intended the second one for emphasis, in which case it is one. If you intended ẓihār, then a divorce and ẓihār are binding upon you, and it is not permissible for you to have intercourse with your wife until you pay the expiation for ẓihār. If you intended an oath or did not intend anything, then a divorce and expiation for an oath are binding upon you.

You can reconcile with your wife before the end of her iddah if this divorce is not the third one.