Starting to work on things other than stat blocks for Part 1. Haven't gotten very far -- just to the Terrain section of Marauder Attack.

This section says that the escarpments about the road cost quadruple movement to enter. Is that a thing in 5e? That is, is there any precedent for more-difficult-than-difficult terrain? I feel like I've seen it somewhere in the PHB, but I can't think where -- some spell description?