UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

Information Statement Pursuant to Rules 13d-1 and 13d-2

Under the Securities Exchange Act of 1934

(Amendment No.     )*

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this schedule is filed:

¨ Rule 13d-1(b)

x Rule 13d-1(c)

¨ Rule 13d-1(d)

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Page 1 of 15 Pages

The name of the issuer to which this filing on Schedule 13G relates is Swift Transportation Company. (the “Company”).

The principal executive offices of the Company are located at 2200 South 75^th Avenue, Phoenix, AZ, 85043.

This statement is being filed on behalf of Sankaty Credit Opportunities III, L.P., a Delaware limited partnership (“COPS III”), Sankaty Credit Opportunities IV, L.P., a Delaware limited partnership (“COPS IV”), Sankaty Credit Opportunities (Offshore) IV, L.P., a Cayman Island exempted limited partnership (“COPS IV Offshore”), Sankaty Managed Account (PSERS), L.P., a Delaware limited partnership (“PSERS”), Sankaty Advisors, LLC, a Delaware limited liability company (“Sankaty Advisors”) in its capacity as the investment manager for a managed account client over which it has discretionary authority to acquire, dispose of, and vote securities, and Prospect Harbor Credit Partners, L.P., a Delaware limited partnership (“PRO”).

Sankaty Credit Opportunities Investors III, LLC (“COPS III Investors”), a Delaware limited liability company, is the general partner of COPS III. Sankaty Credit Member, LLC, a Delaware limited liability company (“SCM”), is the managing member of COPS III investors. Sankaty Credit Opportunities Investors IV, LLC (“COPS IV Investors”), a Delaware limited liability company, is the general partner of COPS IV. SCM is the managing member of COPS IV Investors. Sankaty Credit Opportunities Investors (offshore) IV, L.P., a Cayman Islands Exempted Limited Partnership (“SCM Offshore Investors), is the general partner of COPS IV Offshore. Sankaty Credit Member (Offshore), Ltd., a Cayman Islands Exempted Limited Partnership (“SCM Offshore Ltd.), is the general partner of COPS IV Offshore Investors. Sankaty Managed Account Investors, LLC, a Delaware Limited Liability Company “SMAI” is the general partner of PSERS. SCM is the managing member of SMAI. Prospect Harbor Investors, LLC, a Delaware limited liability company (“PRO Investors”) is the general partner of PRO. SCM is the sole member of PRO Investors. Mr. Jonathan Lavine is the managing member of each and SCM and SCM Offshore Ltd. Sankaty Advisors has entered into an Investment Management Agreement with a managed account client pursuant to which it has authority to acquire, dispose of, and vote securities on behalf of such client. Sankaty Advisors disclaims beneficial ownership of the shares beneficially owned by such client.

The Reporting Persons have entered into a Joint Filing Agreement, dated June 30, 2011, a copy of which is filed with this Schedule 13G as Exhibit A, pursuant to which the Reporting Persons have agreed to file this statement jointly in accordance with the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934.

The principal business address of COPS III, COPS IV and COPS IV Offshore, PSERS, Sankaty Advisors, and PRO is 111 Huntington Avenue, Boston, Massachusetts 02199.

COPS III, COPS IV, PSERS, Sankaty Advisors, and PRO are organized under the laws of the State of Delaware. COPS IV Offshore is organized under the laws of the Cayman Islands. Mr. Jonathan S. Lavine is a citizen of the United States of America.

The class of equity securities of the Company to which this filing on Schedule 13G relates is Class A Common Stock (“Common Stock”).

The CUSIP number of the Company’s Common Stock is 87074U 101.

As of the close of business on December 16, 2010, COPS III owned 700,000 shares of Common Stock of the Company, COPS IV owned 1,070,650 shares of Common Stock of the Company, COPS IV Offshore owned 1,379,350 shares of Common Stock of the Company, PSERS owned 218,750 shares of Common Stock of the Company, Sankaty Advisors had discretionary authority to acquire, dispose of and vote 437,500 shares of Common Stock of the Company, and PRO owned 568,750 shares of Common Stock of the Company. As of the close of business on December 31, 2010, COPS III owned 854,656 shares of Common Stock of the Company, COPS IV owned 1,307,197 shares of Common Stock of the Company, COPS IV Offshore owned 1,684,099 shares of Common Stock of the Company, PSERS owned 267,080 shares of Common Stock of the Company, Sankaty Advisors had discretionary authority to acquire, dispose of and vote 534,160 shares of Common Stock of the Company, PRO owned 694,408 shares of Common Stock of the Company.

No person other than the respective owner referred to herein of the shares of Common Stock of the Company is known to have the right to receive or the power to direct the receipt of dividends from or the proceeds from the sale of such shares of Common Stock of the Company.¹

As of the close of business on December 16, 2010, COPS III owned 0.95% of the Common Stock of the Company, COPS IV owned 1.46% of the Common Stock of the Company, COPS IV Offshore owned 1.88% of the Common Stock of the Company, PSERS owned 0.30% of the Common Stock of the Company, Sankaty Advisors had discretionary authority to acquire, dispose of and vote 0.60% of the Common Stock of the Company, PRO owned 0.78% of the Common Stock of the Company.

Together, as of the close of business on December 31, 2010, COPS III, COPS IV, COPS IV Offshore, PSERS, Sankaty Advisors, and PRO owned or had discretionary authority to acquire, dispose of and vote 7.29% of the Common Stock outstanding of the Company. The aggregate percentage of Common Stock reported owned by COPS III, COPS IV, COPS IV Offshore, PSERS, Sankaty Advisors, and PRO is based upon 73,300,000 shares of Class A Common Stock outstanding, which is the total number of shares of Class A Common Stock outstanding as of December 15, 2010 based on representations made in the Company’s Form 424B4, filed with the Securities and Exchange Commission on December 17, 2010.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.

Not Applicable.

Not Applicable.

Not Applicable.

Not Applicable.

By signing below, the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Dated: June 30, 2011

Exhibit A

AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13G

The undersigned hereby agree as follows:

Dated: June 30, 2011