The NHMRC Road Accident Research Unit at The University of Adelaide with the support of The Federal Office of Road Safety has conducted a study into the effect of free travelling speed on the risk of involvement in a casualty crash in a 60km/h urban speed limit setting.
A case control study method was used where the distribution of speeds of casualty crash involved cars were compared with the distribution of speeds of non crash involved cars.
It was found that in a 60km/h speed limit area, the risk of involvement in a casualty crash doubles with each 5km/h increase in travelling speed above 60km/h.
The full report is available
The results of this study were also reanalysed using a more sophisticated method: