Abstract: The present invention provides a simulator which when used aboard a vehicle normally undetectable by a traffic signal control system (e.g. A.C. energized buried sensing loop type which detects predetermined changes in the characteristics of an electromagnetic field due to the presence of a detectable vehicle therewithin), will substantially simulate the characteristics of a detectable vehicle within its field and thereby cause any activation of the system. Operationally, the simulator derives an electrical signal from the field (e.g. via a receiving antenna), converts the electrical signal into a modified transmittable signal of an amplitude which when impressed upon the field (e.g. via a transmitting antenna) simulates electromagnetic influence of a detectable vehicle therewithin which is sensed by the detector circuitry and activates an associated traffic signal controller to provide the necessary signals (e.g. a green arrow) to allow safe and unobstructed traffic flow at an intersection.