Dogs just plain enjoy chasing people, things, cars and even cats. They really do not intend to hurt anything it is just something fun for them to do. It is important for you to know how to stop your dog from chasing.
A dog chasing creates fear in others and can cause an accident as well. As the owner it is your responsibility to a stop your dog from chasing.
It will take more than simply yelling at your dog or if your dog chases something to hit him. In fact these tactics will usually not work at all to stop your dog from chasing. A more proactive method is better than a reactive method in this situation.
The very best thing you can do to prevent your dog from chasing is to not allow your dog to be with other dogs who chase things. This probably will require your dog to be in a fenced yard or on a leash until he has been trained and will follow your commands.
It is important for an owner to be aware of the signs his dog gives before a chase. Usually dogs will give some kind of indication before starting a chase. It may be an intense long stare at something, raising one of his legs, or some other behavior. Once you learn your dog’s indication you can actually prevent the chase from even occurring. It should not take you long to know your dog well enough to identify what his indications of a chase would be since this is actually a habit for your dog
Obedience to basic commands is required for a dog to stop chasing. Once your dog has been taught the basic commands of sit down and come here, it will be fairly easy to get him to stop chasing.
I order to train your dog to be obedient to voice commands, you need to identify a toy or treat he likes. Lay down this toy or treat within 10 ft of your dog and watch for the dog to start to go toward the object. When the dog starts to approach the object, give the voice command to come to you or sit down. Speak calmly and friendly to the dog and when he obeys give him the toy or treat.
With consistency, time, and patience your dog should be trained to stop chasing within a week.