Which function allows a radar unit to display a second speed based on the next fastest signal?

The function that allows a radar unit to display a second speed based on the next fastest signal is known as target speed discrimination. This function enables the radar unit to differentiate between multiple signals in the detection area, displaying the speed of the most relevant target while simultaneously picking up on additional signals that may be nearby.

This capability is crucial for law enforcement officers as it helps them identify and verify the speed of vehicles in traffic where there may be several moving objects. The importance of this function lies in its ability to provide clarity during speed enforcement operations, ensuring that the officer can accurately ascertain which vehicle is exceeding speed limits, even when multiple vehicles are in close proximity. It enhances the reliability of speed readings provided by the radar unit, making it an essential tool for ensuring effective traffic law enforcement.