Having lived at Uluru in the NT for 4 years and having to drive to Alice Springs (454km one way) at least once a month I agree that the faster you were driving the more concentration, especially when there is nothing to look at in the middle of the desert. When doing 100km/h out there you felt like you were doing about 60km/h and became quite boring and potential for micro-sleeping increased.
I say up the speed limit.............I also drive around 120km/h most of the time now in QLD between Townsville and Cairns, except when the rain/wet season kicks in.
T