As a runner I have had success with running toward a charging dog and acting crazy. Several times that I have done that the dog has run the other way. The key is to make all sorts of hand motion and noise.
It's trickier if you're on a bike, but then I usually opt to kick them as they chase me. So far, I've outrun the ones that weren't deterred after being kicked.
If you live in a normal country that actually has animal care centres where they humanely kill stray dogs, you probably don't have problems to which the above advice applies.