Briefly describe the scope and type(s) of discovery available (e.g., depositions, interrogatories, etc.):
49 CFR 21.15(d)(2) - ". . . rules or principles designed to assure production of the most credible evidence available and to subject testimony to test by cross-examination shall be applied where reasonably necessary by the officer conducting the hearing. ... All documents and other evidence offered or taken for the record shall be open to examination by the parties and opportunity shall be given to refute facts and arguments advanced on either side of the issues."