What has excessive lighting been proven to increase the risk of?

Excessive lighting has been proven to increase the risk of secondary crashes primarily because it can create a false sense of security among drivers. When emergency scenes are heavily illuminated, drivers may underestimate risks and fail to notice critical factors, such as the presence of other vehicles or obstacles. The bright light can disrupt their ability to properly judge distance and speed, leading to a miscalculation when navigating around the incident scene. This is especially critical in situations where drivers are already distracted or focused on the illuminated area, causing them to overlook the surrounding conditions.

In contrast, while excessive lighting may influence non-injury accidents, vehicle overheating, and traffic congestion, these factors are not as directly linked to the specific risk of secondary crashes as the primary hazards presented by an emergency vehicle scene. Hence, the connection between excessive lighting and secondary crashes is more pronounced, making it the most accurate answer.