When working with a full bridge the deck width can be changed from the LBC > Geometry tab

• Open the LBCX file and navigate to Geometry tab
• Expand Roadway Elements and select XCECT01 from the tree under Selection on the left:

• In the Cross-Section window click on Add Template and enter the Station where the width is changing, enter the new width for the planes and enter the PG offset.  In the example shown below my width is changing by a total of 10' and the deck is flaring out on the right side.  The center of the Deck is 5' to the right from the PG node so the PG Offset is 5':

• Enter additional templates for every transition.  Add a template for the end of the bridge also to complete the cross section information: