When parking a lorry on the road in this situation, are you obliged to switch on the position lights or parking lights?

In the photo, at night, on an unlit road, a flatbed lorry with its rear lights on is standing at the right edge of the roadway. When you park a lorry on the road in such conditions, you must switch on the sidelights (position lights) or parking lights. The answer is: yes.

The Road Traffic Act states that the driver of a power-driven vehicle, in conditions of insufficient visibility, during stopping not caused by traffic conditions and during parking, must use the front and rear sidelights or the parking lights; all lights may be switched off only when parking in a place lit well enough to make the vehicle visible, or off the roadway and the shoulder. The road in the photo is unlit (the street lamp is not on), and the lorry is standing on the roadway, so none of the exceptions applies. A dark load body without lights is invisible until the last moment - a driver approaching from behind will see it only within the range of their own headlights and at 90 km/h will not be able to brake in time. A vehicle without a trailer, like the one in the photo, may use the parking lights only on the roadway side; a combination with a trailer or semi-trailer longer than 6 m must have the full sidelights on.

Legal basis: Art. 52 para. 1 and 2 of the Road Traffic Act (Prawo o ruchu drogowym)