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.