If you’re interested in the statistics of speed the US has a long history of looking at this. In the 1970's the federal government instituted the 55 mph maximum speed limit on all federally funded roads and highways (except Montana which had no speed limit on many highways though now it is inline with the rest of the states). The campaign was called "55 Saves Lives" and was introduced to save both lives and gas.

After about 5 years of this campaign the feds tossed it in the trash heap with a lot of other good intentions. It turns out that 55 didn't save any lives and in fact may be responsible for many deaths. What was learned is that speed doesn't kill, rather it is speed variance that kills. If you had 90% of drivers traveling within +-5 of 55 and 10% going +10 mph or greater more accidents would result. This data was corrected for historical accident prone areas, population growth, car safety improvements and several other variables.

I found the info more then plausible and rather enlightening and obviously so did our government legislators. The study is more then 25 years old now but it might be possible to find in on the web somewhere.

Most US speed limits outside of cities and metro areas are 65 or 70 mph with a few at 75. These seem to be rates that most feel comfortable driving at and will minimize speed variance.

Good luck with the new changes in the NT.