Quantifying the Upper Levels of Hydén’s Traffic Safety Pyramid Using Global Data

Abstract

Hydén’s pyramid qualitatively displays the number of conflicts and road user crashes in different severities. Fatal crashes are on the top of the pyramid, undisturbed passages mark the base of it. To quantify the pyramid, open data from the German Accident Atlas and closed data from the Berlin Police have been analysed with respect to time of the week, crash severity, and conflict-type. The data display distinctive weekly patterns that may reflect the traffic state at the hour of the week. Analysing the ratio among these levels for different crash severity levels seems to demonstrate that serious crashes and fatal crashes sometimes follow a different pattern than property-damage-only crashes, or crashes with lightly injured people. A similar result holds true for the conflict-types. This may indicate that their genesis is a mixed bag: sometimes, the mechanisms are different, and sometimes, they are not.