I agree but I can't help feeling like this anecdote kind of reinforces my first point. I don't believe we should be quite so speed limit obsessed. I think we should be able to keep our eyes on the road and all drive to the capabilities of our vehicles under the conditions. German autobahns have demonstrated this can work (if you have a decent road system).

We shouldn't be getting tired from checking the spedometer, we should be getting tired from driving, and when we are tired we should be stopping.