The 6x6 posts will just be sheared off to little avail. If you're on a
slope up, putting in a retaining wall of about 2' high will stop all but the
big trucks without any legal problems if you put a fence at the top of the
wall to keep things from falling off the wall. If you're level, there's
always a few large (4'-8' diameter) rocks that will provide a good splat
zone but you do want several to fill out other parts of the yard.
Brick fences will work only if they are reinforced as the bricks do tend to
break apart easily. The only thing the general fence does is to attempt to
show the driver where the road isn't.
Finally, there is always the steel barrier to slow down the drivers. You
might want to work with your neighbor to work the barrier all the way around
the turn.

--
Why isn't there an Ozone Hole at the NORTH Pole?