Study of the Determining Cause in Traffic Accidents Involving Pedestrian Collisions: Speeding

Abstract

This paper investigates the determining cause in a pedestrian traffic accident, focusing on the role of speeding in accident avoidability. The objective is to determine, through scientific reconstruction based on classical mechanics and probabilistic modeling, whether excessive speed constituted the determining causal factor. The case study was adapted from “Acidentes de trânsito: análise da prova
pericial (Aragão, 2009)” and analyzed using Monte Carlo simulation with the Niewtun Crash Reconstruction Companion, version 2025. The methodology enabled estimation of initial and impact speeds with uncertainty propagation, and comparison between retrograde distance (DR) and no-escape distance (DNE) under different regulatory speed limits. Results indicate that, under a 60 km/h speed limit, speeding was the determining cause of the accident. In a hypothetical 70 km/h limit scenario, improper pedestrian entry becomes the predominant causal factor. The study reinforces that determining cause analysis must focus on physical avoidability, not merely on formal traffic violations.