Let me expound my previous answer: You used a speedlight and the camera was set to a 2 second exposure. When you pressed the shutter button, the shutter opened, the speedlight fired, and that created the exposure of the people and the reflections in the sign, fence, tree and cars.
However, the shutter stayed open for another 1.9833 seconds. With an aperture of f/3.03 and an ISO of 200, that's more than enough for the LED streetlight in the background to be recorded as a streak of light across the sensor as you moved the camera down and to the left after you saw the flash. The odd shape of the light trail is cause by either a high-speed dimming of the LED that basically turns the LED on and off really fast. So fast you can't see it. Or a result of the rectification of AC to DC and the LEDs are pulsing on/off 120/second. 100/second if the AC system is 50Hz.
Um, streetlights don't move, but cameras do. As stated above, it was a 2-second exposure. Press the shutter button, shutter opens and flash fires, and as he pulls the camera down, the shutter is still open. The foggy colors in the background are motion-blurred items lit by the street light. No motion blur close, as the close area was very dark; just the flash exposure, as was intended. Also, the flash exposure was low because of the street sign reflection fooling the metering.