We have a dog that is 1/2 lab and 1/2 Jack Russell Terrier. He isn't quite a year old. He has developed a really bad habit of chasing cars. We live near a hunting club and this time of year there are quite a few cars that go by. He will not listen to us at all when it comes to chasing the cars - he just goes after them and chases them for quite a ways. I hate that he chases cars because I hate to have a dog jump out while I am driving and chase along side of me. I am terrified that he will get hit. We have tried penning him up and he always digs/jumps out. We have tried everything we can think of and are to the point of considering buying a shock collar. I was curious how many of you have tried shock collars and were you sucessful with it? What are the pros and cons of shock collars? Which brand/size would you recommend? Where did you purchase yours from? I am trying to as much research as I can as they are a bit expensive. I would appreciate in and all info/advise you might have! Thanks!