Lettering comes in many forms, none more important surely than street signage that direct people. And within street signage comes texts literally written on to the road to advise motorists of, well, in this case speed.
I do not doubt that the Australian Government has a code on street typography. Do they have one on legibility? Notice how this sign is being eroded by nature.
And see this earlier post as it looks as if the piece was given a paint job.