Dogs Chasing Cars
If your dog is chasing cars, you are right to be concerned. This can be a very dangerous behavior — both to the dogs and passers-by. The dogs can be injured by cars; and the behavior will usually progress from car-chasing to bicycle and skate-board chasing and even just chasing kids running down the street.
Unfortunately, it’s a very difficult behavior to stop. Dogs are predators and they instinctively chase moving objects. You don’t say what breed your dogs are — some breeds, such as herding dogs and sight hounds are more likely to chase than others, but all dogs will chase. And the dogs don’t need other dogs to teach them to do this — they’ll figure it out all by themselves!
This is a very common behavior in rural areas where dogs aren’t fenced. They’re allowed to run free but they have no need to search for food, which is what a wild dog would be doing, so they get into trouble. Think of them as latch-key kids — coming and going as they please with no supervision. Some of the common problems free-roaming dogs get into are getting into garbage, barking, chasing (cars, bikes, cats, etc.), packing up (which leads to all kinds of trouble), and impregnating female dogs (which means there’s a whole bunch more dogs running free to get into trouble!).
Unless you are there at all times to manage the chasing behavior, you will not be able to stop it — that means that the dogs are never outside unsupervised and even if they are supervised, you need to be able to control them. Further, it will require an intensive training program and regular maintenance.
My best advice is to put up a fence so the dogs can’t chase, and keeping the dogs in the house with you — that’s really where they want to be, anyway. Electronic fences are inadequate. Once a dog figures out that in exchange for a small shock he can jump the fence and be free, he’ll do it; unfortunately he’s unlikely to jump back into the yard — it’s not that motivating and the shock isn’t worth it. Chaining a dog can be very dangerous and cruel if the dog is not properly taken care of — potential hanging, chafing around the neck, having to eat and live near or in it’s own excrement, never being with the family, etc.
Many people feel that fencing their dogs in a rural area is mean and unnecessary, but in reality it’s much better for the dogs, yourself and your neighbors.
Raising Canine has a school for dog trainers which focuses on operant training for dogs, dog behavior, working with clients and addressing client compliance, and the science behind behavior modification.