Walking and car trip turmoil

Question
Hi Sue,
I have an 8 month old Border Collie, named Bella.  She has taken to house and yard training well and is quick to learn.  However, when I take her for a walk or in the car the problems begin.  If she sees a person, cyclist or another dog it is like she is possessed she barks, growls, goes up on her hind legs and does not listen to any commands.  When strangers come to the house, she does not behave in the same way and she is happy to see visitors.  Bella is getting bigger and stronger and harder for me to calm and control. I come home after a walk or car trip in tears because she is acting like an aggressive dog when i know she is not, please help as i feel I am losing control.
Kind regards,
Meghan

Answer
Hi Meghan,
Your situation with Bella is a common one and is one that takes persistence and repetition to break.  This type of barking can be caused by your dog providing an alert/warning as to potential danger ( where the bark is aggressive combined with growls), by being startled by a different movement or sound, being fearful (can be very similar to alert/warning), being bored, being playful, or even a combination of the above.  It sound to me that Bella is probably alerting you to potential danger. Some dogs do not like the "invasion" of fast moving objects.  
So the key is to let her know the barking behavior is not wanted without having her think you are also "barking" at the same object.  When the dog is aggressively barking, they probably only have their whole being intent on that one thing...it is your job to distract her.
The goal to success here is persistence. Allow Bella to bark sometimes and you're going to have trouble. Correct EVERY time she makes noise and you've got a good chance.
I suggest you be pro-active when taking walks...see a potential barking problem and instantly shorten the lead so you have more leverage with her.  Secondly, what type of collar are you using?  A choke chain would work the best for this type of problem.  With that you sternly say one word and give a firm tug on the lead so she knows that behavior is not accepted.  As I said, aggressive barking may not control with that I experiment with what does get her attention off of the object.  I have tried a small spray bottle with water in it to spray the dog in the face with the wrong behavior which did work to divert the dogs attention. But as I mentioned previously, whatever method you decide to use...you are the boss be stern (that doesn't necessarily mean loud), repetitive in the same reprimand EVERY TIME the bad behavior occurs, and   when the dog does QUIT BARKING  give a praise like "good no-bark" and a pat every time the dog minds you.  
Done properly, this has been very successful in my training.
Try that and should you have any further questions, please feel free to ask.