"For driving skills, 93% of the U.S. sample and 69% of the Swedish sample put themselves in the top 50%; for safety, 88% of the U.S. and 77% of the Swedish put themselves in the top 50%."

McCormick, Walkey and Green (1986) found similar results in their study, asking 178 participants to evaluate their position on eight different dimensions of driving skills ...when all eight dimensions were considered together it was found that almost 80% of participants had evaluated themselves as being an above-average driver."

It's called "Illusory superiority". Fortunately, I am better than those who think they are better." ;)