Under what condition are drivers prohibited from passing a funeral procession on a two-lane roadway?

Drivers are prohibited from passing a funeral procession on a two-lane roadway specifically while in a properly identified procession. The law provides this consideration as a mark of respect for the grieving families and to ensure the safety and dignity of the procession. Funeral processions are typically accompanied by a series of vehicles that may have funeral flags or other identifying marks, which signals to other drivers the importance of maintaining a safe distance and not disrupting the flow of the procession.

This restriction is in place to prevent accidents and uphold the solemn nature of a funeral, allowing those in the procession to travel together without interruption. The other conditions such as heavy traffic, red lights, or nighttime driving do not inherently relate to the special considerations required for funeral processions. Hence, the correct answer emphasizes the unique protocol surrounding these events to enhance public safety and respect for those mourning their loss.