Embodiments of the present invention are directed to a computer-implemented method of simulating forward traveling voltages in a simulated circuit. The method includes inserting a traveling wave probe, via a processor, at an observation point of a simulated transmission line. The processor applies a first signal at an input of the traveling wave probe, and evaluates an output of the traveling wave probe. The processor next determines an instantaneous wave forward voltage and an instantaneous wave backward voltage at the traveling wave probe, and displays the instantaneous wave forward voltage and the instantaneous wave backward voltage via an output device.