Under which circumstance is it illegal to use a cellphone while driving in South Carolina?

In South Carolina, it is illegal to use a cellphone while driving through construction zones because these areas demand heightened attention and caution due to the presence of workers and equipment. The law reflects a commitment to safety for both drivers and those working in these potentially hazardous conditions. Using a cellphone in construction zones can significantly distract drivers from the task of navigating safely, increasing the risk of accidents. This regulation is part of broader efforts to enhance roadway safety and protect workers in vulnerable positions.

The other options do not reflect scenarios where cellphone use is prohibited. For instance, using a cellphone while stopped at a red light or when parked does not pose the same risks to roadside safety. Additionally, the suggestion that it is always legal to use a cellphone while driving would contradict specific laws designed to mitigate distractions in high-risk areas like construction zones.