The secretary serves as the principal advisor to the president of the United States on all matters relating to transportation.

Ronald Reagan's second secretary of transportation, Elizabeth Dole, was the first female holder, and Mary Peters was the second.

[6] In April 2008, Mary Peters launched the official blog of the secretary of transportation called The Fast Lane.

[7] On January 23, 2009, the 16th secretary, Ray LaHood, took office, serving under the administration of Democrat Barack Obama; he had previously been a Republican congressman from Illinois for fourteen years.

Elaine Chao, who served as the secretary of labor under President George W. Bush, was nominated by Donald Trump on November 29, 2016.