Never had that issue myself. If it does occur, it's likely there's not much we can do about it because it's probably due to the particular way the game engine deals with that type of flying craft.
Only noticed it once I re-installed Chih's sub-mod, due to the massed infantry most planets get in it.
How is the hit-box that collisions are tied to set up for speeders ?
If the hitbox could be set to MUCH smaller than the craft (which is supposed to be airborne in the LAATs case) it'd slide thru crowds a little easier.
Also, I think part of the issue is the game's pathfinding having always sucked too.