Which of the three risk factors is the one least involved in the causes of traffic accidents?

# Explanation The **vehicle factor** is the one least involved in the causes of traffic accidents. Although mechanical failures can occur, they represent a very small proportion of incidents. In contrast, the **human factor** (distractions, fatigue, excessive speed) and the **road and environment factor** (weather conditions, poor road conditions) are responsible for most accidents. Therefore, prevention focuses mainly on driver behavior and road conditions.