Electronic traffic control equipment is highly susceptible to upset or damage from externally and internally generated electrical noise and transients. Lines providing electrical power and cables interconnecting equipment to sensors, communications systems, or peripheral hardware provide a direct path for the conduction of electrical transients, such as lightning, electrostatic discharge, and inductive switching transients, and electromagnetic interference (EMI), as from nearby radio, TV, radar or mobile communications transmitters, into unprotected equipment. The objectives of this report are to: (1) define the electromagnetic threat to traffic control equipment from these sources, and (2) identify and define protection practices, procedures and techniques to mitigate the effects of the various electromagnetic threats. The protection practices, procedures, and techniques encompass proper grounding, bonding, shielding, and terminal protection, including the use of filters, amplitude limiters and cable interface designs. (A)
Abstract