Superiority bias
Svenson (1981) surveyed 161 students in Sweden and the United States, asking them to compare their driving safety and skill to the other people in the experiment. For driving skill, 93% of the US sample and 69% of the Swedish sample put themselves in the top 50% (above the median). For safety, 88% of the US group and 77% of the Swedish sample put themselves in the top 50%.