Which lights should you turn on if you stop at the side of the road in the dark to let a passenger get out of the car?

If you stop at the side of the road in the dark to let a passenger get out of the car you should turn on the parking lights.

You must always switch to parking lights when you have parked or stopped on a road with poor visibility or insufficient lighting, so that other road users are able to see the car. This applies even if you only have to park or stop for a short while.