A couple down at St Albans west of SYD.

Derestriction signs are discontinued in NSW, prohibitied from the "NSW Speed
Zoning Guidelines".  Councils had been installing them on crappy roads and
the authorisation for them to do so was withdrawn back in 2004.

AS1742.4 of 1999 catalogues the sign as an R4-2, meaning ".... that no speed
limit applies to the road beyond the sign".  (applies 'Under another law of
this jurisdiction' at ARR25).

In the UN Convention, the sign is cataloged as a C,17a "End Of All Local
Prohibitions Imposed On Moving Vehicles".

On Australian roads the REPLACEMENT for this sign is the R4-12 - "End Speed
Limit" sign, contains the word "END" with a number in a circle representing
the ceasing speed-limit.  Thi sign falls back to the rural default, both in
AS1742.4 of 1999 AND in ARR.

The derestriction sign *may* be re-introduced to remove a speed-limit, but
only to 'lengths of road'.  The exception rather than the rule.

Jeremy.

I spent a few days in the Northern Rivers region last week,
and those signs are all over the place down there.
They actually seem to work - I noticed that where there was
a speed limit, people seemed to try to drive at the limit,
even if it was excessive for the situation. But where the
derestriction signs were, they seemed to drive at
appropriate speeds.

Nothing to do with speed.
Anti-porn: This sign was first adopted in the middle ages by anti-porn
crusaders as no mooning and/or don't show your arse crack in public.

Road sign: It went on to be the side of the road type (as shown in your
photos) to depict the angle your steering will be after hitting a
pothole. Of course there were also the round objects this sign was meant
to ban.. such as all round road wheels.

Branding cattle: Circle Bar Ranch claimed it as their own for a short
while until they found their cattle were being used by small green aliens
for horrible experiments... and often tortured for not saying anything
except moo and mmoooooo.

Witchcraft and/or demon worshiping: Used by people too poor (how poor)
they could not afford a pentacle.

Birth control: Somewhat similar to the above. The victim, usually
naked dumb blonde female is tied, legs together, on the bar section.

Early wheel: The one single spoke wheel was invented by an aboriginal but
failed leaving behind a bent spoke that he threw away and it came back
and hit him in the head.

Toilet is closed: A plank was thrown across a circular pit to prevent
crappers soiling the garments of pit workers in the years 815 to 920. The
view from below is even used today on a sign to ban all sorts of crap. Of
course the crappers found the plank was preferable to accidentally
falling into the pit to crap.
Then in 921 came 'crap to conditions', where one had to look for pit
workers.

Al