Mary Elizabeth Peters (née Ruth; born December 4, 1948) is an American government official who served as the 15th United States secretary of transportation from 2006 to 2009, under President George W. Bush.

She received her bachelor's degree in business administration and management from the University of Phoenix[2] and subsequently attended a three week seminar at the John F. Kennedy School of Government.

In an interview, Peters said that the National Highway System would run out of money by the end of the aughts without substantial changes and, rather than raise taxes, some states should turn to toll roads leased to private corporations to fill gaps.

[13] Mary Peters held a press conference on September 5, 2008 to report that Highway Trust Fund payments to states, including her native Arizona, would be cut back because federal fuel tax collections were dropping.

While she was Secretary of DOT a rule was passed stating that dogs, cats, miniature horses, pigs as well as monkeys could be considered emotional support animals, and therefore could be taken by commercial airlines in the cabin.