Thx MADMAN for the video, I'd like to explain the problem, if you have a small drill that removes say 5pixels of rock, then you get a gap that is 5 pixels wide, if you need twenty pixels to fit a vehicle through, then the player has to dig in four places wide to make a tunnel big enough to fit through. Imagine as he moves across to drill one of these 5 pixel sections, that he moves just 4 pixels across, that will result in the gap being only 19 pixels wide, this can happen anywhere down a long tunnel, or worse at a curve or bend, so when you vehicle tries to fit through it works fine for some distance then part of the way down it gets to a 19 pixel wide section and it will catch on the side of the tunnel by one pixel. Its probably not so bad for a small vehicle getting stuck in a small tunnel, but imagine you have a huge vehicle 500 pixels wide and it can't get through a tunnel because it is only 499 pixels wide, you will be looking at it and thinking it should fit through. Getting stuck is annoying and frustrating for the player, so its a better game design, to make gaps bigger than the sizes of the vehicles, so we standardize vehicles into set sizes, small medium or large, and only create gaps that are (bigger than) small medium or large, basically we dig out 'blocks' so paths line up, and the player doesn't get stuck - or at least it is obvious that they will, or will not, fit in a tunnel. In the video, you can see that the developers have coded it so you can't create rocks less than a certain size - the size of that pinnacle. That is their 'minimum block size' and any thing smaller than this 'explodes into rubble', this prevents thin slivers of rock being created, however the tip of that sliver in a tunnel, would still prevent a large vehicle getting though. its just a question of how small a block size you want to goto.
Currently the AI is served out on the first come first served basis, so the nearest Rock Raider, doesn't get the job, just the first in the line for new orders, I can see that checking the list of available orders and matching these with all the possible tasks, would improve the AI, these could be handed out more appropriately, and we should also add in outside influences, like monsters, so the nearest or best suitable will respond and then delegate their order back to the list for another RR. This is very possible. At the time, too many AI checks would have slowed the game down, but with modern processing power this would be easy.