Truthfully, I have never seen 2-wheel ABS on cars. This was common on pickup trucks for several years, however.
Please tell us which makes and models of cars you have seen with 2 wheel ABS.
Are you sure that a PT Cruiser has only 2 wheel ABS?
P.S. Incidentally, it is not necessary to post the same question three times.
P.P.S. Tom and Ray do not respond to questions in this thread.