Deaf Dog

[Heddi]

I have a deaf red heeler (1.5 years old) that has learned hand signals well. She is kept in the yard (we have an invisible fence) or on a leash at all times. Unfortunately she wants to chase car when I walk her. I have tried stopping, holding her so she can't jump and soothing her as the cars go by. This hasn't helped. How can I help her to get comfortable with moving vehicles?