Tuesday, I was riding my TerraTrike Tour (27 speed with 26" rear wheel) on a straight road at approximately 25mph, close to the top speed I have been able to manage with pedaling alone. I applied the brakes a little too hard and too fast in preparation to pull off of the road for a car I could see approaching from behind me in the distance. The trike snapped sideways violently and overturned, ejecting me onto the road. It happened instantly with no possibility of reacting or recovering. I tumbled and slid for a few seconds in the middle of the road. The trike landed upright in the ditch on the right side.
I sustained several "road rash" scrapes, one that gouged a quarter-inch deep hole about the size of a half dollar just below my elbow. It was serious enough that I went to the emergency room to have it treated. The trike surprisingly had little damage, and I was able to ride it home (thankfully only a half mile). Only the seat bolt was bent. The chain is making a grinding sound and will need adjustment. The brake discs nor the steering linkages/alignment were affected at all. The wheels still roll freely and smoothly.
Just a word of warning that a trike can and will crash at moderate speeds under heavy braking. I consider the accident my fault for braking too hard so abruptly, but it's possible a similar crash could happen with someone attempting an emergency stop/obstacle avoidance at speeds above 20mph.
Otherwise I love my trike. I ride 20-40 miles every 2 days (weather permitting).