From: Winnipeg, MB
I did Adelaide to Darwin in 1984, it was dirt, pot holes and bull dust for most of the journey between Pt Augusta & the Nthn Territory border. North of Alice Springs it varied from a good road to a narrow strip of bitumen. Now its an excellent road unless you are following a Road Train.
Sounds similar to the Alaska Highway, built during the war using mostly US labourers - most of whom were black and had never been in a cold climate before. Nor had the northerners seen a black man, so they were considered exotic.
But the road construction had to deal with extreme cold, bears, black flies, muskeg bogs, numerous creeks and rivers, mountains and permafrost melting because the covering peat had been disturbed. The latter could cause your parked bulldozer to disappear while you were sleeping.
Much of the base of the road was locally quarried rock, which was then covered with gravel. Unfortunately the rock was not soft sedimentary rock, it was slate and the like which form sharp shards when broken up. Erosion of the gravel and frost heaving exposed the sharp edges on the driving surface and tires were routinely shredded.
As late as the 1970s, truckers hauling supplies north routinely carried 4-6 extra tires with them! There were few settlements on the road which meant a tow truck could be hundreds of miles away. Not good if you suffer mechanical problems.
On the up side - during the summer you get daylight or dusk light 24 hours a day so you can cover a good distance before pulling over for a nap in your vehicle.
No matter how bad a situation is, you can always make it worse. - Chris Hadfield : An Astronaut's Guide To Life On Earth