Time zero is when the starter hits the switch. The amber lights slowly brighten over a period of 160 ms (milliseconds). You generally "see" the lights from 20 ms to 60 ms after the started hits the switch, depending upon physical and physiological conditions.

The lights are powered by 120 volts AC line current. You can see the voltage ripple (8.33 ms) current in the waveform as the lamp filaments warm up.