Are yield signs at off-ramps being phased out?

Off ramps do not yield unless they come to a crossing intersection (getting off the freeway). On ramps do as they merge onto the freeway. They haven't gotten around to replacing the signs yet. I am familiar with the ultra short on ramps in S.A. and it's about time they did something. I used to drive an 18 wheeler there. If you're entering faster traffic you have to yield.