I searched around a bit and came across some very interesting articles... To cite the introduction to "Examining the self-enhancement bias: professional truck drivers’ perceptions of speed, safety, skill and consideration" by D. Walton
"When the public are asked to choose factors that can make roads unsafe, they consistently identify as the main factor, ‘poor driving skills and attitudes’, and as the secondary contributing factor, ‘speeding’ (LTSA, 1997a). Human factors are estimated to contribute to 80±95% of accidents (Lewin, 1982) and ‘travelling too fast for the conditions’ is the leading factor in motor vehicle fatalities (LTSA, 1997a). Despite this public awareness, people overestimate the number of accidents that occur on the road (Slovic, Fischho€ & Lichtenstein, 1982). Paradoxically, drivers overestimate their skill and safety compared to others (Svenson, 1981), and regard the average person as more likely to be involved in an accident (Guerin, 1994; Matthews & Moran, 1986). Theparadox, to make the point clear, is that the public on the one hand, think ‘the roads are dangerous’;and on the other, think themselves safer, more skillful and less likely to have an accident than others."
And then, although old, I find this very funny... From "ARE WE ALL LESS RISKY AND MORE SKILLFUL THAN OUR FELLOW DRIVERS?" by Ola Svensson.
"Results
The distributions of the judgments are shown in table 1 for the two groups and the two questions respectively. The table shows that most of the Ss in the group viewed themselves as safer and more skillful drivers than the rest of the group. The medians for the distributions of safety judgments in table 1 fall in the interval 8 l-90% for the US group and between 7 1 and 80% for the Swedish group. This indicates that half of the Ss believe themselves to be among the safest 20 (US) or 30 (Sweden) percent of the drivers in the two groups respectively. In the US group 88% and in the Swedish group 77% believed themselves to be safer than the median driver.
The medians for the distributions of skill judgments fall in the interval 61-70% for the US group and between 51-60% for the Swedish group. Of the US sample 46.3% regard themselves among the most skillful 20%. The corresponding number in the Swedish group was only 15.5%. In the US sample 93% believed themselves to be more skillful drivers than the median driver and 69% of the Swedish drivers shared this belief in relation to their comparison group.
In summary, there was a strong tendency to believe oneself as safer and more skillful than the average driver. In addition, there seemed to be a stronger tendency to believe oneself as safer than and more skillful than the average person."
As I said, a bit old but still worth to notice IMO...