A more thorough explanation:

The Secretary of Transportation is a member of the President's cabinet who is responsible for leading the U.S. Department of Transportation. This department oversees all aspects of transportation in the United States, including highways, airports, railways, and public transportation.

For example, the Secretary of Transportation might work on initiatives to improve the safety of highways and reduce traffic congestion. They might also be involved in developing policies to promote the use of public transportation and encourage the growth of the aviation industry.

Overall, the Secretary of Transportation plays a crucial role in ensuring that transportation systems in the United States are safe, efficient, and accessible to all.