Why do dogs chase cars?  

probably for the same reason they chase a ball, this is whwere i say cats are so much smarter than dogs, they wouldn't belittle themselves to chase a ball or wouldn't see anything in chasing a car...

Many of the breeds that chase cars are members of herding group. These dogs instinctively chase things that move. Some breeds are not at all interested in cars...
Also if people allow their dogs to just hang out in the yard, rather than being in a fenced in area, in the house, or tethered out on a cable, the dogs who just "hang out" often get themselves into trouble by chasing cars, as they dont have any supervision. In most towns these days there are pretty strict leash laws, but in the country people seem to think they can just let the dog "hang out" in the yard or whatever.

I'm sure it's the strictly instinctive predator/prey mentality. If something moves off, they become prey and a dog's instinct is to go after it.

Even a dog that is normally docile will chase you if you get up and run off. They might not hurt you, but they'll give chase. It's just what dogs do.

That is a very good question and I am not completely sure why a dog would want to chase a car since you are right they can not eat the car,and the car could run them over if it chose to,I think it is because dogs are easily entertained and they find pleasure in chasing things like cars and balls,and also because I think dogs are very curious creatures,and they like to find out what it is going on,and maybe chasing the car is there way of trying to figure out what it is or where it is going.

I think the dogs chase anything that's moving. They just chase for fun. Sometimes i'm really worried that the dogs will get bang by the car at the back. It's also dangerous for the biker, I think dogs chase at them as well.

Can I catch it? Can I catch it? Can I catch it? If they are herding dogs it is in their instinct to herd it in the right direction. But if they are not herding dogs I think that nature is calling them to weed them out of the gene pool.

I think they don't like the sound of cars.Or the car must have splashed water or dust in its face.I think dogs do not like moving or running objects.If i run in front of a dog the dog will come running after me.I once saw a dog running after a person cycling.In the office i saw a dog running after the company bus.

A bit like an OLD MAN chasing a young women

Will he know what to do with it once he has made the catch, at his age he will most likely to have forgotten what it was all about in the first place.

Both are amusing to watch.

How cruel is life,

HICCUP/