Why is Hannah lost in Act 3, Scene 4?

Hannah Pitt has just arrived in New York in Act 3, Scene 4. Her son Joe is supposed to pick her up, but he never shows. Annoyed, Hannah boards a bus that she hopes is bound for Brooklyn. It drops her in the Bronx, and when she asks the driver if she is in Brooklyn he nods. The driver does not speak English and thinks it is just polite to nod.