ABSTRACT
In-depth accident study is a method useful as a complement to more quantitative accident approaches, to further the research in malfunctions in the driving system and their determinants. They help to precisely define the adapted countermeasures to address the right targets. The road users are considered central in such an analysis, to understand the nature and the reasons for the difficulties and malfunctions they encounter when on the road. This paper presents some key elements on in-depth accident data collection and elaboration, on the sequential analysis of the accident process; the functional analysis of human failures and their factors. As part of the traffic system, the powered two-wheelers have become a component both crucial and critical. In the second part of the paper, they are taken as an application example of what can bring an in-depth accident approach to the understanding of the difficulties faced by road users.
