What is the function of a high-mounted stop lamp in light vehicles?

The function of a high-mounted stop lamp in light vehicles is to improve visibility when braking. This lamp, often positioned higher than the standard tail lights, serves to alert drivers behind the vehicle that it is slowing down or stopping. By placing the stop lamp higher up, it helps ensure that the signal is visible even if there are larger vehicles, like trucks or SUVs, in the same line of sight. This feature is particularly critical in preventing rear-end collisions by providing a clear and visible warning to other drivers when the vehicle is braking.

The other options do not accurately represent the purpose of a high-mounted stop lamp. For instance, the lamp does not enhance audible warnings—its function is purely visual. It is also not designed to indicate lane changes, which relies instead on turn signals. Lastly, while daytime running lights improve vehicle visibility during the day, they serve an entirely different purpose and are not associated with braking signals. Thus, option C is the most accurate description of the high-mounted stop lamp's function.