Your dog reacts the same way as my newly acquired rescue dog. At the dog park she's absolutely fine with dogs and people, but on a leash around the neighborhood she goes insane when she sees another dog, even 100 yards away, and when someone (without a dog) passes us, she pulls my arm off.

Using the halti has definitely helped, but what I'm really looking forward to is the behavior/obedience classes we will start in January, where there will be a number of people with dogs on leashes in a small area and she will have to behave around them.