Chairperson Chairperson Committee Member Member Lead Director Lead Director
 Audit CommitteeBoard Affairs CommitteeCompensation CommitteeIndependent Director
Diane C. Creel 
Diane C. Creel
Director since March 2014


Diane C. Creel
Ms. Creel has served as one of our directors since March 2014. She retired as Chairman, Chief Executive Officer and President of Ecovation, Inc., a subsidiary of Ecolab Inc. and a waste stream technology company using patented technologies, in September 2008, positions that she had held since 2003. Previously, Ms. Creel served as Chief Executive Officer and President of Earth Tech, an international consulting engineering firm, which is now part of AECOM, from 1992 to... 
    Committee Member
Mickey P. Foret 
Mickey P. Foret
Director since March 2003


Mickey P. Foret
Mr. Foret has served as one of our directors since March 2003. He served until 2002 as Executive Vice President and Chief Financial Officer of Northwest Airlines, Inc., an airline company, and Chairman and Chief Executive Officer of Northwest Airlines Cargo, Inc., a transportation and logistics company. Mr. Foret was employed in various management positions at Northwest Airlines from 1992 until 1996 as well as from 1998 until 2002. Mr. Foret previously served as... 
Chairperson    Committee Member
Senator William H. Frist, M.D. 
Senator William H. Frist, M.D.
Director since November 2009


Senator William H. Frist, M.D.
Senator Frist has served as one of our directors since November 2009. He has served as a partner at Cressey & Company LP, a private investment firm, since 2007. He also served as Distinguished University Professor at Vanderbilt University from 2008 until 2010. He served as a United States Senator for Tennessee from 1995 until 2007 and was Majority Leader of the United States Senate from 2003 until 2007. Senator Frist has served as a director of S... 
  Committee Member   Committee Member
Lydia H. Kennard 
Lydia H. Kennard
Director since August 2007


Lydia H. Kennard
Ms. Kennard has served as one of our directors since August 2007. She is currently President and CEO of KDG Construction Consulting. Since March 2007, she has also been a Principal of Airport Property Ventures, an operator and developer of aviation facilities. Ms. Kennard served as the Executive Director of Los Angeles World Airports, the airport authority for the City of Los Angeles, from 1999 to 2003, and again from 2005 to February 2007. Ms. Kennard has bee... 
  Chairperson   Committee Member
Timothy R. McLevish 
Timothy R. McLevish
Director since November 2012


Timothy R. McLevish
Mr. McLevish has served as one of our directors since November 2012. He currently serves as Executive Vice President of Kraft Foods Group, Inc., a manufacturer and marketer of packaged food products. He served as Executive Vice President of Kraft Foods from 2011 until 2012 when Kraft was separated into Kraft Foods Group and Mondelēz International, Inc. From 2007 to 2011, he served as Executive Vice President and Chief Financial Officer of Kraft Foods. Before ... 
Committee Member    Committee Member
Gen. Joseph W. Ralston, USAF (Ret.)  Lead Director
Gen. Joseph W. Ralston, USAF (Ret.)
Director since October 2003


Gen. Joseph W. Ralston, USAF (Ret.)
General Ralston has served as one of our directors since October 2003. He has served as Vice Chairman of The Cohen Group, an international business consulting firm, since 2003; as a director of Lockheed Martin since 2003; and as a director of The Timken Company since 2003. General Ralston’s military career began in 1965 and concluded in 2003, when he retired from active duty. General Ralston’s military career was highlighted by his service as V... 
Committee Member Committee Member Chairperson Committee Member
John D. Roach 
John D. Roach
Director since February 2003


John D. Roach
Mr. Roach has served as one of our directors since February 2003. He has served as Chairman of the Board and Chief Executive Officer of Stonegate International, a private investment and advisory services firm, since 1997; as a director of Ply Gem Holdings since 2004, and as a director of Verisign, Inc. since August 2007. He previously served as the Executive Chairman and Chief Executive Officer of Unidare U.S., Inc., an industrial welding and safety supplier, from... 
Committee Member   Committee Member Committee Member
William H. Schumann, III 
William H. Schumann, III
Director since March 2014


William H. Schumann, III
Mr. Schumann has served as one of our directors since March 2014. He retired in August 2012 as Executive Vice President of FMC Technologies, Inc., a provider of technology solutions for the energy industry. He served as Chief Financial Officer of FMC Technologies from 2001 to 2011 and Chief Financial Officer of FMC Corporation (the predecessor to FMC Technologies) from 1999 to 2001. Mr. Schumann has served as the non-executive Chairman of the Board of Dire... 
   Committee Member Committee Member
David N. Siegel 
David N. Siegel
Director since March 2014


David N. Siegel
Mr. Siegel has served as one of our directors since March 2014. He is President and CEO of Frontier Airlines, a privately held airline company, and serves on its board of directors. He was a Director of Republic Airways from October 2009 to December 2013, including serving as Lead Independent Director from May 2011 until January 2012 when he was appointed President and CEO of Frontier, at the time a wholly owned subsidiary of Republic. Prior to joining Frontier, Mr... 
    Committee Member
Douglas  W. Stotlar 
Douglas  W. Stotlar
Director since March 2007


Douglas W. Stotlar
Mr. Stotlar has served as one of our directors since March 2007. He has served as President, Chief Executive Officer, and director of Con-way Inc., a transportation and logistics company (previously known as CNF Inc.) since April 2005. He served as President and Chief Executive Officer of Con-way Transportation Services, Inc., a regional trucking subsidiary (“CTS”), from 2004 until 2005. He also served as CTS’ Executive Vice President and Chief Operating Offi... 
   Committee Member Committee Member
V. Paul Unruh 
V. Paul Unruh
Director since March 2014


V. Paul Unruh
Mr. Unruh has served as one of our directors since March 2014. He retired as vice chairman of Bechtel Group, Inc. in June 2003. During his 25-year tenure at Bechtel, he held a number of management positions including treasurer, controller, and chief financial officer. He also served as president of Bechtel Enterprises, the finance, development, and ownership arm, from 1997 to 2001. Mr. Unruh is also a certified public accountant. Mr. Unruh is currently a member of... 
    Committee Member