Which example constitutes an imperfectly displayed signal aspect?

An example of an imperfectly displayed signal aspect is when a white light is shown where a colored light should be. In signal systems, colors convey specific meanings; colored lights indicate certain conditions, such as proceed, caution, or stop. A white light does not convey the same information as a color-coded signal and can lead to confusion or misinterpretation of what action should be taken.

For instance, colored signals typically represent different operational statuses that are critical for safety and efficient train operation. The introduction of a white light, which could be easily confused with signaling conventions, disrupts the clarity that colored signals provide. Therefore, a white light in place of a colored light fails to meet the established guidelines for an accurate signal display, making it an example of an imperfectly displayed signal aspect.