The first thing we have to remember when we talk about chasing behaviour is that our Border Collies have been bred for generations to herd fast animals that tends to run away!!
Which are the reasons behind some Border Collies will start chasing things like cars, bikes or joggers? There is no one answer so I'm going to give you a couple, sometimes it's a mix of more then one reason or one is trigger by the other one:
FEAR! dogs use behaviours that come first in their genetic behaviours to cope with something that worries them in the environment. Usually if you need to cope with something means you are not confortable or you are afraid of it. They don't know how to cope with a big metal thing that makes terrible noises when going past and they try to herd it to control it. Border Collies can be noise sensitive and a very loud bike or car could easly create a fear response.
PREY DRIVE! They are not stimulate enough and they have to give that pray drive an outlet. As the breed has been bred to use that pray drive on sheep for long hours a day, you understand that if you don't channel that pray drive they will find a way to use it. You need to be very careful that you are not reinforcing that prey drive with the wrong activity, for example ball throwing. But we wil talk about this later on.
The age that Border Collies start with the car chasing or bike chasing behaviour is very different, depending on a lot of factors.
There is something called the sentitive period or fear period during which BCs will be more senstive to get scared to things especially if they don't know them. Keeping a puppy in the house until they finish their vaccination at 12 weeks and not allowing them to gently socialise them with things can lead to so many different problems, car chasing being one of those.
If you keep your puppy indoor until 12 weeks and then you take them out and they experience a car going past very quickly and noisy, without having seen one from a distance or getting use to it gradually, it's easy for them to get scared of it.
Once they are scared of it a typical mechanism will start: the STALKING. They spot the car in the distance and they start stalking it. The Collie EYE is one of the most powerful tool in the canine world! It can move bigger animals from a distance; it can control big flock of sheep that run around crazy. Your little Collie puppy thinks that they can stop, control, block that thing that moves and makes a noise. They start stalking but that doens't help, the car keeps moving so they try to physically stop it! The CHASING sequence starts and usually they then start generalizing that behaviour to other things that move, so from cars they will start with bikes and joggers although they are not really afraid of them. Once the stalking and chasing behaviours are started it can only get worst as stalking and chasing are very reinforcing behaviours for a herding breed. They find a mental benefit in doing it, they get an adrenalin rush that can become addictive! They found their own little task or job to do and Border Collies are prone to OCD behaviours so a task becomes a repetive behaviour.
What happens after that is a cascade of consequences:
the owner gets frustrated and start telling the pup to NOT DO that behaviour, by pulling the puppy back. The frustration is inevitable as a new owner doens't know how to deal with it. The pup thinks that the frustration is directed at him/her and it just increases the stress. Stress lead to more coping mechanism so the dog finds chasing to be not only an outlet for prey drive and fear but also for the added frustration
collars and some harnesses are usually not helping as while the pup pulls towards the car, that collar pulls on the neck creating pain, with a consequence of lack of oxygen going to the head as the wind pipe is pressed not allowing much air in. Even a haness can be very bad if not fitted correctly and not every harness is a good harness. Le's not talk about slip leads, they are even worst as they choke even more the air out of your puppy and create serious pain and dinscomfort. Head collars have a place in training but I prefer not to use them unless is the last resort.
then you try treats but most of the time they are not working. The stress is too high and most dogs won't take food. When the stress is too high the digestive system shuts down and stalking/chasing is much more rewarding then food anyway for you Border Collie.
You are now frustrated, running out of distractions as they won't take any, start buying different harneses and head collar to solve the problem but there is NO TOOL that will solve the problem. There is only knowladge, patience, time and understanding.
What can you quickly do to help:
breath, stop and tell yourself : It's not my puppy's fault. There is no point getting angry at my puppy
Remove the collar and get a good harness with a ring in front and a double ended lead to help you controlling your dog a bit better (e.g. dog copenhagen or perfect fit)
Keep distance from cars. Don't walk your puppy on a busy road. They won't get used to it. Flooding is an old technique that expose the dog to the stimulus that triggers the unwanted reaction at a close distance and for a prolonged time of exposure, but it won't work as your puppy is already rewarded by the stalking and chasing behaviour and it's a technique I won't reccomend anyway for different reasons that I won't explain now. If you need to walk your dog choose a quiet time of the day or drive your pup somewhere quiet.
take away any situation which yout dog can practice that behaviour in: the garden, the window, the car. Block the visual and use a covered crate in the car
start a positive desensitization training starting from very far away where you puppy is able to be calm and take food and play with toys. Start just with the noise and then with the visual stimulation, but keep your distance!
use the best positive reinforcer for your puppy, a high value treat that you know will work. Drop the supermarket/pet shop treats, you need the real deal. Meat, homemade treats with high meat content, cheese.
If your puppy has just started this behaviour there is a good chance to stop it if you do it properly before it becomes too high rewarded. If you dog has been doing it for a long time your journey is going to be a bit longer.
When I mentioned about prey drive, how to channel it and how not to make it worst by playing with the dog the wrong way I meant this: the ball that flies and rolls is like a running animal for your dog, they love it and they could carry on for ages. The problem is that by repeating this behaviour over and over again you are reinforcing the pray drive without control and boundries. My puppies don't play with balls until they are much older and not before I have taught them some self control, control on movement exercises and until I have channeld that prey drive on to a toy that I can hold the end of. You are much better playing to chase a long toy that you can hold so that the game is between you and your puppy that allow your pup to chase a ball away from you that you have no control on. That ball will be a car, a sheep, a bike. And there is no retrieving those things, but your puppy doesn't know.
Last but not least, never use punishment! Punishment is not a long term solution. You want your dog to trust you, rely on you and live an happy life. You want to build a positive bond where you are a good leader to follow, to trust, to listen not to fear more the the car they are afraid of. Share this article with all your herding dog owners friends as this can help a new owner to avoid the problem to rise as well as help you to act straight away to modify the behaviour and to understand your puppy better!