An auxiliary device and system for traffic light detection and communication. The auxiliary device is positionable adjacent to a traffic light. The auxiliary device includes at least one light pipe positionable adjacent to at least one traffic indicator disposed on a surface of the traffic light. The at least one light pipe is capable of carrying a light output from the least one traffic indicator to the auxiliary device. The auxiliary device includes a sensor for sensing the light output, and a processor operatively connected for computer communication to the sensor. The processor receives a measurement from the sensor. The measurement is associated with the light output. The processor detects a state of the light output based on the measurement, and transmits the state to one or more remote vehicles.