I have to agree that trikes, on a whole, are wider than uprights. I don't think that's a particular safety issue. However, every recumbent trike I've seen is lower than the average two wheeled bent, and I think that's critical. The rider is lower and less visible, as well as having less ability to see. Basically, I view anything that reduces the visibility of a bike and rider is a negative thing. I really think visibility is the key factor. A car driver cannot avoid what they do not see, and may not avoid what they see poorly.
My solution for my wife's trike is a tubular aluminum staff ~5 feet high. On the top are four bright lights facing to either side, front, and back. This is in addition to another light facing forward, and two more mounted on her helmet. The staff itself is fabricated from old tent tubing—very strong, stiff enough but still flexible. Even if the driver cannot see the trike or her past the curve of the car body, the lights will be at or near eye level and still visible.
Paranoid? Who? Me? You're darn right I am!
