Don’t agree with Damon. 55mph isnt a good idea on motorways and I doubt for a moment that anyone would follow it, so used to driving at 70mph (which is the speed limit) for so long. Nor do I think raising it will help, if the speed limit now is 70, people drive at +85mph on the motorways, and by raising it to 80, more people will drive at +90mph.
I actually believe that changes in the speed limits or similar isnt quite the way to go, rather a large portion of drivers need re-education in driving. The longer the time since learning to drive means the more time you learn bad habits. I think theres more benefits in leaflets on road conduct (the highway code in the UK), reminders of speed limits on the motorways, looking after cars (tyre tread depth, oil checks, brake checks etc) The only tests here in the UK that im aware of post-drivers test is the compulsory eye test for OAPs. Im not suggesting that people are re-tested and failure nulifies their license, but a refresher course/leaflets every 5years or so.