EXHIBIT 99.1

                            CERTIFICATION PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


         In connection with the Annual Report on Form 10-K of Yellow Corporation
(the "company") for the year ended December 31, 2002 as filed with the
Securities and Exchange Commission on the date hereof (the "Form 10-K"), I,
William D. Zollars, Chief Executive Officer of the company, certify, pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002, that:

         1. The Form 10-K fully complies with the requirements of Section 13(a)
or 15(d) of the Securities Exchange Act of 1934; and

         2. The information contained in the Form 10-K fairly presents, in all
material respects, the financial condition and results of operations of the
company.

         Date: March 6, 2003

                                           /s/ William D. Zollars
                                           -------------------------------------
                                           William D. Zollars
                                           Chairman of the Board, President and
                                           Chief Executive Officer