http://casr.adelaide.edu.au/speed/vol-1.htmlThis study suggests that your crash risk is minimized when you are going faster even than the average vehicle on the highway. (See figure 2.2) And this is all *before* you correct for higher speeds meaning less time on the road.
The figure indicates that your crash risk is minimized when you are going
slightly faster than the average speed of the highway. According to the figure, more than 10 mph over the average speed and your crash risk increases above that of maintaining the average speed. Furthermore, the figure does not take into consideration the increase in damage, injury, or fatality at the higher speed when a collision does occur. Beyond that the figure also doesn't adjust for the fact that impaired drivers tend to drive slower, meaning that the figure is skewed since impaired drivers while slower are significantly more likely to be involved in a collision. If the graph were adjusted for this bias, it is likely that the minimized risk would be at the average speed.