What does a yellow arrow signal indicate?

A yellow arrow signal serves as an important warning to drivers that the light will soon change to red. This signal indicates that those currently in the intersection or approaching it should prepare to stop, as the right-of-way is about to shift. The intent of the yellow arrow is to alert drivers to the imminent change in traffic control, helping to prevent accidents and ensure a smoother flow of traffic.

In this context, the other choices do not accurately capture the purpose of a yellow arrow signal. For instance, while a yellow arrow might suggest caution, it specifically warns that the signal will transition to red, rather than simply indicating caution without context. It also does not instruct drivers to stop immediately, as there may still be time to safely clear the intersection if they are already in motion when the yellow arrow appears. Lastly, it does not provide any indication of a right turn directive. Thus, recognizing the yellow arrow as a signal of an impending red light is vital for correct road etiquette and safety.