I really have no clue how to get rid of escape tunnels under roads. I have tried everything, I cant build over them, I cant simply get rid of them. Any help?
This is a known issue and has been acknowledged by Introversion. It is bug #0004914 http://bugs.introversion.co.uk/view.php?id=4914
This is a bug which got fixed. The fix went live with the recent update Alpha 32.
Well You could just make it so they can't escape by expanding your land and making a double perimeter wall (they can't tunnel under) and road gates with guards deployed at the gates so when prisoners dig out they will need to walk to the front and be bought by a guard