The study that showed a double crash risk at 65km/h versus 60km/h was conducted in Adelaide by Road Accident Research Unit Adelaide. You can get the 1997 study (Volume 1 = findings, Volume 2 = data) and some commentary at this web page: http://casr.adelaide.edu.au/speed/ RARU Adelaide did a follow up in 2001 about rural speeds: http://casr.adelaide.edu.au/ruralspeed/RURALSPEED.PDF I've only scratched the surface of the first study, V1, and am finding the incessant discussion of speed and crash risk utterly grating. The paper also reads like a bit of jackboots fanatical fanboi for speeding enforcement... some of what's said borders on social commentary... I have to say though, that I'm struggling a bit with how it's summarising things. If someone could interpret this paragraph for me I've be greatly appreciative!: Just as an aside, those two studies are referenced in the following MUARC paper (sponsored by the TAC): www.monash.edu.au/miri/research/reports/muarc276.pdf "Impact of lowered speed limits on urban and metropolitan areas, 2008." which seems to be underpinning much of Victorian enforcement efforts.