I agree that there are varying degrees of intelligence, but I believe that you cannot measure it with a number or even two. I also think intelligence is contextual. For example, I have met many folks that have tested very well on intelligence measures that do well in calculus, but get creamed by higher levels of mathematics because of the abstraction. These same seemingly intelligent individuals can also be seen to do some really stupid shit "in the real world", lacking common sense.
As an interesting aside, the first "IQ" tests were the Army Alpha used during the first world war - designed and administered by RM Yerkes. Among many dubious outcomes of this testing Yerkes legitimitazied Polish jokes, ignoring the language barriers these individuals experienced. I won't go on, but two books well worth reading are The Bell Curve by Herrnstien and Murray and The Mismeasure of Man by Stephen Gould. The Bell Curve is a shockingly recent use of statistics and IQ to stake the claim that minorities have inferior intelligence, it's an excellent read on how not to use numbers to quantify humans. The Mismeasure of Man is an excellent history of the abuse of measures of IQ and really is a must read in my opinion. Gould's book is also the cause of my hesitation to believe that intelligence can be measured.
Ignoring all of that, I don't know whether the distribution of IQ would be normal or not. I do know that IQ scores are normalized by the group administering the exam, meaning that no matter what the raw data is they make it a bell curve. With all the prep courses and societal pressure put on these exams I would not be surprised to see that the raw data is skewed.
But all of that is here nor there, in this thread we are talking about societal attitudes/intelligence in relation to driving. In this case people seem to toss their brains out the window. As an example, it has become a societal norm for people to talk on cell phones while driving, despite evidence that this is dangerous. Here in NY it is illegal, and yet twice I have seen police officers in squad cars talking on them :blink: In the case of intelligence in relation to driving I don't think we can count on a bell curve of intelligence; I would say at least 65% of the population is retarded and the percentage is increasing yearly.
I'll have to think about whether that last sentence needs a smiley or not.