What should drivers ensure when using flags instead of lights?

When drivers use flags instead of lights, it is crucial that the flags are clearly visible. This ensures that other drivers and pedestrians can easily see the signals being communicated. Clear visibility is essential for safety on the road, especially in conditions where visibility might be compromised, such as at night or in poor weather. This not only facilitates better communication regarding traffic control but also helps prevent potential accidents.

While other options may seem important, such as ensuring the flags are oversized, illuminated, or in good condition, the primary concern is visibility. A flag that is clearly visible will effectively communicate its intended message, regardless of its size or condition, as long as it is adequate for the purpose. Therefore, prioritizing clarity in visibility is the most crucial aspect when using flags in lieu of lights.