In addition to The Physics of towed vehicles, you might also read the two stickies at the top of Dingy topic that includes 30 threads, three hundred comments and 300,000 looks. This is a well debated topic with a lot of contrary information.
For breakaway protection a correctly installed base plate and towbar, is backed up by correctly installed safety chains. Aux braking system will merely shorten the glide path of an improperly installed toad after it has broken away. The toad may still go into oncoming traffic on the left or gas stations on the right