[Code of Federal Regulations] [Title 23, Volume 1] [Revised as of April 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 23CFR650.809] [Page 238] TITLE 23--HIGHWAYS CHAPTER I--FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 650--BRIDGES, STRUCTURES, AND HYDRAULICS--Table of Contents Subpart H--Navigational Clearances for Bridges Sec. 650.809 Movable span bridges. A fixed bridge shall be selected wherever practicable. If there are social, economic, environmental or engineering reasons which favor the selection of a movable bridge, a cost benefit analysis to support the need for the movable bridge shall he prepared as a part of the preliminary plans.