T-bones are very hard to get out of especially when using mecanem wheels. The wheels have such little traction that you can't drive out of a t-bone like 254. Without using different bumper material or chassis, the best way is to have your driver get stuck in a few and then learn how to avoid them or drive spin or drive well enough to get out of them. I was caught in tons in the first district I drove and then was not caught in them hardly at all after. In my opinion the easiest way to avoid them is to be constantly moving. Also if you know that one is coming you can essentially spin out of it, if they do not hit you directly in the middle of your bumpers. Spin the corner the your robot the same direction that the robot is coming at you. Watch at about 1:04 when 3663 gets pinned by 1983.
https://www.youtube.com/watch?v=WbHHUtCGc1c