I belong to several dog groups across social media platforms and many of those groups have members with collies or other herding dog breeds. At least once a week, someone posts a story of their dog chasing cars, motorcycles, bicycles, skateboards, or joggers. Chasing cars and motorcycles is dangerous not just for dogs, but for drivers swerving to miss those dogs. And dogs who chase bicycles, scooters, and runners are not just a nuisance; they are risky to those who are simply trying to go about their business. Over the 30 years I've been in practice, I've had more than one client whose dog was struck by a moving car when the dog went to chase after it (happened with dogs both on and off leash), and multiple clients whose dogs have knocked people off of their bikes and skateboards, and a few who've bitten runners and cyclists as well. Throwing up your hands and saying that nothing can be done because they are herding dogs and that's just what they do is not acceptable, nor safe. Plus, this isn't just a "herding dog problem." Lots of dogs chase things they shouldn't, posing a danger to themselves, their owners, and the public at large.
Dogs, by design, chase moving targets. Their ancestors were alert to movement in the environment as that movement could mean potential prey for them to catch and eat, or that they could be prey for another animal! Just because chasing something that moves IS a dog thing, doesn't mean that you can't redirect that natural behavior to more appropriate outlets. Dogs who love to chase birds, squirrels, and bunnies will likely enjoy chasing games with a flirt pole. I've had a couple of clients scoff at this suggestion saying that playing with a flirt pole with their dog will just make their dogs more efficient chasers and that's just rubbish. Dogs are going to chase moving targets regardless of whether you address the behavior or not. Better that you acknowledge that drive and give them an outlet for it so that when you do have to correct and redirect them away from inappropriate chasing, they'll not become overly frustrated. This applies to herding dogs too. Giving them an outlet for their natural inclinations is good for them; learning to herd chickens, goats, sheep, etc. is challenging for their minds and bodies and isn't just about chasing moving targets. It's about learning to use their bodies and the amount of pressure they apply by how close they are to those other animals, to get them to move in a certain direction. Learning to herd is a thinking dog's sport and one which requires practice for the handler as well as the dog. Ozzie is a much better herding dog than I am a herding dog handler!
Okay, so you've given your dog an outlet for their enthusiasm for the chase. Now, how do you get them to stop chasing everything else? First off, if you have a dog who chases cars, don't let them off leash in an area that isn't fenced and where they can take off after a vehicle. I know that seems obvious, but the number of times someone has told me their dog chases cars only to follow up with the fact that the dog is regularly off leash where there are cars, is mind-boggling. Second, begin working with them at home and in your yard where you are able to control what they see and hear. Depending on how good your dog is at "leave it," you may need to do this exercise with them on leash first. Get their attention and toss something away from you. When they begin to move to go get it, tell them "leave it," and hold your hand out with an obvious treat. If they are on leash, you can put a small amount of pressure on the leash when you say "leave it," to ensure that they turn toward you and away from the object. You will want to use really desirable rewards for this exercise so that your dog, even if he loves fetch, is more interested in listening to you than picking up the object. Once you are able to toss any object and call your dog away from pursuing it, you are ready to work out in the real world.
Regardless of what your dog chases, you are likely to see or hear those things in a busy park setting. Start on a day, or time of day, when the park is less populated (or when there are likely to be fewer cars going by, for example) and at a fair distance from the road. For most chasers, if you are 30 feet or more away, they are alert, but less likely to bolt off. Work with your leashed dog on some very basic commands like sit, down, touch, look at me, and go sniff. When they alert to a car/bike/scooter, say "leave it," and put a little pressure on their leash as you say their name. When they glance your way, happily say "YES!" and give them that high value treat you gave them at home when you taught this behavior. Remain at that distance for several training sessions until your dog is relaxed about cars/bikes/scooters going by, and perhaps even ignores them in favor of sniffing or working with you on other behaviors. Over a period of sessions, you will move closer and closer to the street/sidewalk where the objects your dog chases can be found. Don't move closer too quickly or your dog will simply bolt before you can redirect them. And don't make the mistake of pushing them too hard or too long in a single session. Keep your training sessions short and frequent (10 minutes a day is a great way to start). Do try to do a session with your dog every day; doing this reinforces all of those attentive basic behaviors as well as working on the problem of chasing inappropriate objects.
If your dog chases bikes, scooters, skateboards, or runners, you can enlist the help of friends to work on this problem. Again, working at a safe distance, have your friend bike/skate/jog by you and your dog, ignoring you both. Gradually over time, work closer and closer to your friend's location. You may need to reward your helpful friends for these sessions as well!
Finally, if your dog resists all of this and is unable in real world situations to be redirected from inappropriate chasing, then it is up to you to protect them from those situations that can trigger the behavior. This means keeping them on leash and walking them at off peak times and in off peak locations where they are least likely to encounter whatever it is that they like to chase. You will want to continue to practice the above outlined exercises as your dog's behavior can still improve over time with persistence and patience on your part. You just don't want the behavior to continue without addressing it as it will not get better on it's own, nor is it safe to just ignore a dog who chases inappropriate objects.
As always, if you have questions about your pet's behavior, you know where to find me.