An screenshot over here:
Well I have created an improved version of wania1.tri piece (accidentally a bit darker and with an sphere to increase the polygon count). The standar wania1.tri has passed to be the LOD1 and also i've done a LOD2 with just a plane.
(new)wania1 -> 140 polygons
LOD1-wania1 -> 12 polygons
LOD2-wania1 -> 2 polygons
I've created a 250 pieces highway.
Using the common rendering (and so rendering 250 (new)wania1's): 100fps
USing the LOD with just LOD1: 130fps
USing the LOD with LOD1 and LOD2: 200fps
So it's working and (look's like) it improves the perfomance.
Note: LOD is NOT WORKING with Maniadrive, that screenshot just use one piece of track. Looks like MD is using a custom way to load objects and LOD system only works with elements loaded with raydium_ode_object_box_add (right now)