Superiority bias
McCormick, Walkey and Green (1986) found similar results in their study, asking 178 participants to evaluate their position on eight different dimensions relating to driving skill (examples include the "dangerous-safe" dimension and the "considerate-inconsiderate" dimension). Only a small minority rated themselves as below average (the midpoint of the dimension scale) at any point, and when all eight dimensions were considered together it was found that almost 80% of participants had evaluated themselves as being above the average driver.