Mortimer Leo Downey III (born August 9, 1936) was the U.S. Deputy Secretary of Transportation from 1993 to 2001, making him the longest-serving person to ever hold the post. Downey was originally appointed to the position at the beginning of the Clinton administration, and additionally served as Acting Secretary of Transportation for the first four days of the Bush administration, from January 21, 2001 to January 24, 2001. Prior to his service as Deputy Secretary of Transportation, he was executive director and chief financial officer of the New York Metropolitan Transportation Authority (MTA), where he was instrumental in creating and successfully orchestrating the critically, complex and much needed multi-agency capital plan and subsequent updates. During the Carter Administration, from