Google maps and Route

Does anyone know how to change the route google maps gives you when you ask it for directions? I set two points and it comes up with a route but it says take highway X when I want to take Highway Z. Most of the route is the correct way i want to go but a small part in the middle of the route is not the way i want to go.

With my Verizon GPS it will do that if the settings are for "simplest" route. I don't use the Google program but check to see if there is a setting for "fastest".