Intersections represent 43% of Europe’s injury accidents and 21% of fatalities. Although specifically targeted, intersection accident mechanisms merit further investigation.
This study, part of the European TRACE project (Traffic Accident Causation in Europe), analyzes specific intersection accident causation issues from systemic viewpoints (driver, vehicle and environment) and risk factor research angles (visibility problems, speed, manoeuvres, etc.). Causation analysis uses a three-step methodology. A macroscopic approach highlights the frequency and severity of accidents and determines key scenarios. A microscopic approach, details accident causes. Because the driver plays an important role in the accident process, a dedicated "Human Functional Failure (HFF) analysis" is employed. Finally, risk factors are identified and related to accident configurations.
Project partners and the CARE database supply national and European data. Because CARE does not contain data from all 27 countries, statistical adjustment was necessary.
Partners also provided in-depth databases. The HFF concept is new and necessitated common codification of related data.
Intersection accidents are grouped by common characteristics, such as road layout, driver manoeuvres... Macroscopic analysis identified 3 main scenarios. The “cutting” scenario groups initial perpendicular trajectories and covers 53% of European intersection accidents. The “turn across” scenario combines accidents involving turning manoeuvres on the same road, different direction. Finally the “other” scenarios include rear-end collisions.
In-depth analysis furthered understanding of accident mechanisms and showed mechanisms and countermeasures to be directly linked to right of way rules.
In “cutting” scenarios for example, 60% of drivers without “right of way” failed to look and react before crash, while 70% of opponent drivers braked before impact. Results suggest that the former need help to improve opponent and situational perception while the latter need improved braking and evaluation for earlier avoidance manoeuvres. HFF and related factor identification enable the association of current preventive or curative systems with observed driver needs.