Overheight vehicles are 4.3m and over in New South Wales, and this tunnel is signposted at 4.4m (and probably has a bit of leeway). Trucker often have to deal

Overheight vehicles are 4.3m and over in New South Wales, and this tunnel is signposted at 4.4m (and probably has a bit of leeway). Trucker often have to deal with road limits: they are expected to know the size of their vehicle and pick an appropriate route. And if they don't, they are expected to read the signs along the route that indicate road limits ahead.