Out of curiosity... there was a study where 93% of a sample group (of 161) believed they were above average drivers. What would be the chance that they actually WERE above average drivers?
I think this is a questions to get you to think, not calculate. Believing you are an above-average driver and actually being above average are very different things. (Some of the scariest drivers I know would probably claim to be above average in such a survey.)
If you have a scale for judging actual driving ability or performance, and if that scale is normal (or otherwise symmetrical with a mean that exists), then the mean equals the median, and exactly half of the drivers are above the mean on that scale.