Transient protection for highway traffic control equipment

Electronic traffic control equipment is subjected to a wide range of electromagnetic threats. The electromagnetic environment, which includes lightning, electrostatic discharge, internally and externally generated inductive-switching transients, and radiated electromagnetic interference (EMI) from radio, TV, radar, and mobile communication transmitters, is described. Powerlines and cables interconnecting equipment to sensors, communications systems, or peripheral hardware provide a direct path for the conduction of disruptive and damaging electrical transients and other EMI into traffic control equipment. The relative levels of the various threats are integrated into a set of recommended test waveforms for traffic control equipment.<>