Yeah right!! Every time i get on a motorway, it's congested! I can imagine maybe those who travel at 1am and the roads are dead, but its hardly unsafe at that time of night anyway (assuming roads are clear, no roadworks, dry, no fog, etc!)
and from personal experience, i wouldn't say that the 'women are safer on motorways' statement is exactly true! Ok blokes might speed more but the majority of middle lane hoggers & tailgaters i see are women.