There seems to be a confusion in the minds of some people. Some say that fast driving is the same as dangerous driving. We have all been stuck behind some slow person, which is surely as risky as it encourages others to overtake sometimes inappropriately.
One of the main factors in accidents is fatigue. Hence if the speed limits are increastd, then journey times are shortened, less likely to get tired and less likely to crash.
It seems that there is a rush for things to get faster, high speed rail links, faster planes etc, lets have the same for drivers.