'In a 60 km/h zone or lower, warning signs are placed at a distance of 50-150 meters from the hazard point. Guidelines provided by the Norwegian Public Roads Administration ('Statens vegvesen') have the following to say about the appropriate distance:

If the speed limit is lower than or equal to 60 km/h: 50-150 metres before the hazard.

If the speed limit is higher than or equal to 70 km/h: 150-250 metres before the hazard.

On motorways the warning sign should normally be placed 400 metres before the hazard, and then repeated after 200 metres.