Wider than SD but beware.
Safe title is the area recommended for title and essential information placement in the frame. Anything too close to frame edges may get covered by the TV set cabinet body or lost due to other reasons.
Because of 16:9 aspect ratio the safe title area in HD is wider. However, titles placed at the edge of the HD safe title area will get cropped off by “center crop” downconversion to standard definition video [Fig. 1].
It is wise to consider the 4:3 safe title when titling HD material. You can download safe title charts here:
1080 safe title chart, jpg format
1080 safe title char, tif format with alpha
720 safe title chart, jpg format
720 safe title char, tif format with alpha
Fig. 1. Unprotected Title is Cropped Off in SD 4×3 Center Extraction