A Villager's Wagging Tail&Biting Style:What are all the Ways or Equipments to scare an approaching dog?

call the dog catch for that area. before some thing bad happens or does it have a collar on? find the owners that dog could hurt it self or some one else being able to run free. if that gets you no where they make dog whistlers and they have a new gadget ( i have no idea if it works ) but you push a on and it is suppose to stop any animal give these a try