Exhibit 31.2

SECTION 302 CERTIFICATION

I, Glynis A. Bryan, certify that:

1. I have reviewed this annual report on Form 10-K/A of Swift Transportation Co., Inc.; and

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

Date: April 30, 2007

/s/ Glynis A. Bryan  

Glynis A. Bryan 

Executive Vice President and Chief Financial Officer
(Principal Financial Officer)