Tex. Transp. Code § 201.761

Notwithstanding any provision of this subchapter or any other law, a local government sponsor and the department may enter into an agreement that defines the relative roles and responsibilities of the parties in the preparation and review of environmental review documents for a specific project. For a project for which an environmental decision requires the approval of the Federal Highway Administration and to the extent otherwise permitted by law, the Federal Highway Administration may also be a party to an agreement between a local government sponsor and the department under this section.