Let me start by saying that my dog has been bad recently with barking at other dogs that go by. It seems like the longer we have him, the worse he gets about it. Like, he became more comfortable and confirmed this was his house and so now he is very protective and territorial of it. So, I am working with him on getting him to stop.
If you are taking your dog outside to potty and don't have a fence, I think it's probably best for you to keep her on a leash if she will bolt. If I take my dog out in the front yard to potty, I put him on a retractable leash (only time I use retractable) so he can wander to the spot he needs to, but still have control of him if something were to happen, I still have control.
Perhaps you could consult an animal behaviorist or trainer.
You may get some ideas from these:
There is a girl on youtube who does 100% complete positive training using the clicker training and I think her videos are awesome. (Her dogs are super awesomely trained too...amazing). If you search "kikopup" on youtube you will find her under that user name. But, here are the videos she posted on barking:
I think that a lot of times, especially when a dog is barking and worked up and "in the zone" it's really frustrating and difficult to get them to pay attention to anything else, but be consistent with it. I think you can benefit her by working with her on counter conditioning her towards the things (in her case people) she finds scary, beforehand. I love clicker training and it's been super helpful for me in training my dog. If you haven't tried it, do some research on it and start trying it with your dog. It may help.
My personal feeling is that any type of electric/shock collar should be used as a very last result, after all other methods of training are tried and only if the animals life is going to be at risk if it is not used. I think barking is something that is natural. It's cruel to punish them for that. We just need to teach them when it's not appropriate to bark, or when they don't need to worry about something they are barking at. You can build your dogs confidence about things they don't feel safe around by training. The bark control collar will just make them more fearful.