Occlusion culling + scaling questions

will the engine render the entire static mesh if the player sees only the front half of it? Say i have a 3 mile long road all one object and the player has passed the first 1/2 of the road. Will the engine render the entire 3 mile road because the player can see the other half of it? Does the road need to be broken into smaller pieces and done through level streaming instead?

I am using a third party software road tools to make the roads but it doesn’t let me change the meters setting to centimeters. In Maya i changed the settings to centimeters but it does not change the scale because it was originally made in a different package? Any ideas on what i can do to convert the meters to centimeters?

Thanks