Which department oversees interstate travel in the U.S.?

The Department of Transportation is responsible for overseeing interstate travel in the United States. This department manages the nation's transportation systems and infrastructure, which encompasses air travel, railroads, highways, and other means of transport that cross state lines. Its role includes ensuring the safety and efficiency of travel, as well as regulating transportation policies and funding.

In this context, the Department of Health and Human Services focuses primarily on health-related issues and services, rather than travel regulations. The Environmental Protection Agency deals with environmental protection, regulating pollutants and ensuring environmental health, which does not directly relate to travel oversight. Customs and Border Protection, while integral to managing border and customs issues, is more focused on international travel and immigration rather than domestic interstate travel. Therefore, the Department of Transportation is the most relevant agency when discussing the oversight of interstate travel.