Ground Vehicles & Terrain Info

Vehicles that travel on or in close proximity to the ground are affected by natural and man-made terrain features that can make piloting more difficult. Depending on its difficulty and makeup, terrain reduces a vehicle's speed. In addition, just like with starfighters, the speed the vehicle is moving determines the difficulty of any Pilot (Planetary) checks that might need to be made to navigate the area. In addition, the terrain involved may add further complications to the check.
This only applies to Wheeled & Tracked vehicles, however some specific rules apply for Walkers depending on height.

Difficult Terrain

Light terrain

Rough gravel roadways, clear, dry fields, low hills, and light urban ground or air traffic.
No modifier.

Medium Terrain

Deep mud or standing water less than fifty centimeters deep. Also soft, drifting sand, dense undergrowth, ancient ruins, heavy urban ground or air traffic.
Add Setback dice.

Heavy Terrain

Fast-flowing water over a meter deep, rocky, unstable terrain, thick forests, narrow, winding streets, ruined cities, urban ground or air traffic so heavy that it has completely stopped. Wheeled vehicles typically cannot pass this type of terrain, but tracked vehicles and walkers can.
Add Setback dice.