Heavy rain or snow can significantly impact traffic signal performance in a variety of ways. Firstly, adverse weather conditions such as rain and snow can reduce visibility for both drivers and the signals themselves, leading to difficulties in seeing the traffic lights clearly. This can result in confusion at intersections where drivers may misinterpret signal indications or fail to notice them altogether.
Additionally, water accumulation or snow buildup can obstruct traffic signal equipment, impeding their operation. For instance, if snow covers a traffic signal, it may render the lights ineffective or less visible, creating potential safety hazards at intersections.
Furthermore, heavy precipitation can affect the functioning of the signal's electronic components, leading to malfunctions. The technology used in traffic signals may not be fully waterproof or resistant to extreme weather, which may increase the likelihood of failure during severe weather events.
In contrast, clear skies, sunny weather, and moderate wind generally create favorable conditions for traffic signal visibility and operation, making them less impactful on performance. Thus, heavy rain or snow stands out as the correct choice, as these conditions directly interfere with the reliable functioning of traffic signals.