[talk-au] Highway classifications

[Steve Bennett]

Wondering if any experts here could elaborate a bit on the definitions
of highway=primary, secondary, tertiary at
http://wiki.openstreetmap.org/wiki/Australian_Tagging_Guidelines .
There were a few roads in my area (Glen Huntly) tagged as
highway=primary, even though they're pretty minor roads. I've changed
some to secondary, and some to tertiary, but I really don't have a
good feel for which should be which.

Do we have any objective way of deciding what is a "major through
route within a local area" vs a "minor through route within a local
area"?

Steve