i would have called 911 for breach of peace.
Truck driver: "MAM, my family is with me, you are a stranger, I dont want to talk to you and want you to go away. You are obviously incoherant and I perceve you to be a threat to my family and I will defend them accordingly. This is my last warning: leave us alone".
Prius Driver: "Sir, you......."
Truck Driver: [Pulls out 5 gallon BEAR SPRAY-Pulls trigger] PPPPSSSHHHHHHHHHHHHHHHHHHHHHHHHHH!!!
Prius Driver: AIIGGHH!!!! My eyes!! My eyes!!!! I can't breathe!