Why are lighting conditions significant in a crash investigation?

Lighting conditions are significant in a crash investigation because they can directly impact visibility, which is a critical factor in driving safety. Poor visibility due to inadequate lighting—whether from natural sources like streetlights or the sun, or other environmental conditions—can hinder a driver's ability to see obstacles, other vehicles, or pedestrians, thereby increasing the risk of a collision. When investigating a crash, understanding the lighting conditions at the time can help determine whether they played a role in the incident, such as if a driver failed to see a stop sign or a pedestrian due to darkness or glare.

While determining the time of day is helpful, it does not directly explain how visibility impacted the crash. The relevance of lighting conditions is not limited to nighttime incidents, as even during the day, factors like bright sunlight can drastically alter visibility. Additionally, while lighting can influence the severity of injuries through factors like speed and impact dynamics, it is primarily the visibility impairment that is most critical in assessing causation in collision events. Therefore, the focus on how lighting conditions can affect visibility and contribute to crashes makes this answer the most relevant in the context of crash investigation.