With the right idle speed/torque converter combination, power brakes and a smooth operating throttle, an automatic in traffic can be painless even with a heavy load.
Automatic or manual, traffic jam or not, I'm one who likes to leave lots of room between me and the car ahead. Even with four-wheel disk brakes I don't like relying on the brakes to work instantly. The trucks I drive have good brakes and so does my trailer, but I don't want to be caught by surprise and not have room to avoid a collision.
I hadn't thought of my knee problems as health problems but I suppose they really are.