The route of the highway originally ran between Hobart and Launceston, and passed through the localities which are now known as: Bridgewater, Brighton, Pontville, Mangalore, Bagdad, Dysart, Kempton, Melton Mowbray, Jericho, Oatlands, Antill Ponds, Woodbury, Tunbridge, Ross, Campbell Town, Conara Junction, Cleveland, Epping Forest, Perth, Breadalbane and Kings Meadows.
As part of the National Highway, there have been many on-going changes to the highway since the 1980s.
The southern outlet in Launceston was built, bypassing many Launceston suburbs, allowing motorists to travel from the Breadalbane roundabout, almost directly to the city centre, at full highway speed. Around the same time, the towns of Ross, Oatlands and Kempton were bypassed.
In 2002, a railway line underpass was constructed near Symmons Plains, south of Perth, to create a grade separated rail crossing on the highway itself. Significant numbers of overtaking lanes have also been extended or created.
There is also a plan to bypass an area immediately north of Hobart. This will involve possible bypasses of Pontville, Bagdad and Brighton. There is mounting pressure for Perth and Campbell Town to also be bypassed, but this is unlikely to occur in the near future.