Exhibit 31.2


**CERTIFICATION**





I, David
A. Jackson, certify that:





1.  I have
reviewed this quarterly report on Form 10-Q of Knight Transportation,
Inc.;





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;





3.  Based on my knowledge,
the financial statements, and other financial information included in this
report, fairly present in all material respects the financial condition, results
of operations and cash flows of the registrant as of, and for, the periods
presented in this report;





4.  The registrant’s other
certifying officer and I are responsible for establishing and maintaining
disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e)
and 15d-15(e)) and internal control over financial reporting (as defined in
Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and
have:





(a) Designed such disclosure
controls and procedures, or caused such disclosure controls and procedures to be
designed under our supervision, to ensure that material information relating to
the registrant, including its consolidated subsidiaries, is made known to us by
others within those entities, particularly during the period in which this
report is being prepared;





(b) Designed such internal
control over financial reporting, or caused such internal control over financial
reporting to be designed under our supervision, to provide reasonable assurance
regarding the reliability of financial reporting and the preparation of
financial statements for external purposes in accordance with generally accepted
accounting principles;





(c) Evaluated the
effectiveness of the registrant’s disclosure controls and procedures and
presented in this report our conclusions about the effectiveness of the
disclosure controls and procedures, as of the end of the period covered by this
report based on such evaluation; and





(d) Disclosed in this report
any change in the registrant’s internal control over financial reporting that
occurred during the registrant’s most recent fiscal quarter (the registrant’s
fourth fiscal quarter in the case of an annual report) that has materially
affected, or is reasonably likely to materially affect, the registrant’s
internal control over financial reporting; and





5.  The registrant’s other
certifying officer and I have disclosed, based on our most recent evaluation of
internal control over financial reporting, to the registrant’s auditors and the
audit committee of the registrant’s board of directors (or persons performing
the equivalent functions):





(a) All significant
deficiencies and material weaknesses in the design or operation of internal
control over financial reporting which are reasonably likely to adversely affect
the registrant’s ability to record, process, summarize and report financial
information; and





(b) Any fraud, whether or not
material, that involves management or other employees who have a significant
role in the registrant’s internal control over financial reporting.





Date:  May 6,
2005





By:
    /s/
      David A. JacksonChief
      Financial Officer




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