Using the general label settings to set the orientation of vertical labels

Steps:

1. On the Labeling toolbar, click Labeling > Options.
2. Click the General tab.
3. Type a number between 0 and 30 degrees in the Orientation of Vertical Labels text box.

Positive numbers will force labels of lines oriented slightly West of North to be read from South to North.

Negative numbers will force labels of lines oriented slightly East of North to be read from North to South.

The Orientation of Vertical Labels also applies to polygon labels.

4. Click OK.