The new system aimed to upgrade the signing of destinations, including previously unmarked roads, and to simplify navigation by allowing visitors to follow numbered routes.
[1]: 41 There have been various changes to the system over the years, including a few minor adjustments after a 2011 review by the Road Route Code Advisory Group.
For the purpose of allocation of route numbers the state has been divided into eight zones, each delineated by major highways.
Zone 1 covers a section of the north coast and a substantial inland area to the south, reaching almost to Hobart.
Zone 3 covers the south-east corner of the state, including the northern part of Hobart.
[10] Its southern road boundaries are: Flinders Island is included in this zone.