It's a matter of people's abilities, not what people think is right. And if the speed limit is 100 when the road is mostly empty, many people will still be going 100 on it when it is way to crowded for 100 to be a safe speed.

And that's because the vast majority of people who like to drive fast are bad drivers and should never be allowed to drive anywhere near as fast as they think they should. The good drivers are, as often as not, the ones who know their limitations and drive accordingly. (I am not saying that you, Richard, are necessarily a bad driver. You may be an excellent driver. But if you are, you are not in the majority when it comes to people who like to drive fast.)

You are suggesting that the majority of people shouldn't be allowed to drive at all, just so a small minority of people can drive as fast as their little hearts desire. I am saying that the people who like to drive fast should realize that they don't own the road, and make accommodations for those who cannot safely drive as fast as they do (which is most people). There's a really big difference between these two things.