You must use parking lights when your vehicle is parked at night on a road (or lay‑by) where the speed limit is over 30 mph.

Core rule (Highway Code style)

  • At night, if you park on a road or lay‑by with a speed limit above 30 mph , you must switch on your parking lights / sidelights so your vehicle stays visible.
  • This applies even if the road “seems” quiet or has some street lighting; the key trigger is the speed limit , not how busy it feels.

When they’re not normally required

On roads with a speed limit of 30 mph or less , you usually do not have to use parking lights if:

  • You’re parked close to the kerb and facing the correct direction of traffic.
  • You’re at least about 10 m from a junction and in a proper parking place or lay‑by.

Good practice and safety

Even where they’re not strictly compulsory, using parking lights at night is wise when:

  • The street is poorly lit or unlit.
  • Your car is near a bend, junction, or narrow road where it might be hard to see.

Think of parking lights as a low‑glow safety marker: bright enough to show where your car is, but not so bright that they dazzle others.

TL;DR:
You’re parked on the road at night – you must use parking lights when the speed limit is over 30 mph ; below that, they’re generally optional if you’re parked correctly, but still a smart safety choice in dark or awkward spots.

Information gathered from public forums or data available on the internet and portrayed here.