Surfaces produce effects, driven on sounds, and other behaviour. Note that surface type is not generally used for out of bounds behaviour. As such, out of bounds areas may use any combination of surface types or flags.

extract from SURFACE_TYPE

id	Name	Desc	Courses
1	Solid	Pavement, tunnel walls/floor	Koopa Troopa Beach, Rainbow Road
2	Dirt	Several courses, edge of water	Royal Raceway
3	Sand	Dirt track and oob beach sand	Koopa Troopa Beach
4	Cement
5	Snow	Ice cave interior	Frappe Snowland, Sherbet Land
6	Bridge	Bridges and guardrails, castle bridge	Royal Raceway
7	Dirt Off-road
8	Grass
9	Ice		Sherbet Land
10	Wet Sand		Koopa Troopa Beach
11	Snow Off-road
12	Rock Walls	Also used for choco walls	Choco Mountain
13	Dirt Off-road		Kalimari Desert
14	Track Ballast	The dirt used in railways	Kalimari Desert
15	Cave	Cave interior	Jungle Parkway
16	Rope Bridge	Rickety	Jungle Parkway
17	Wood Bridge	Solid wood
252	Boost Ramp	Locks speed to ~60km/h	Jungle Parkway
253	Out of Bounds	Lakitu activates on touch	Jungle Parkway
254	Gravity Ramp	Boost ramp that locks speed with reduced gravity	Royal Raceway
255	Walls/Ramps	Walls and ramps	Koopa Troopa Beach