The United States Department of Transportation (DOT) is a cabinet-level federal agency established in 1966 and operational from 1967, tasked with developing and coordinating national transportation policies to ensure a safe, efficient, and modern transportation system[1][2][3]. Its mission is to enhance mobility, safety, and economic competitiveness by overseeing aviation, highways, railroads, maritime transport, and pipeline systems across the country[2][4]. Historically, the DOT consolidated 31 separate federal transportation functions under one department to streamline policy development and program administration[2]. Before its formation, transportation responsibilities were scattered, with the Under Secretary of Commerce for Transportation managing many functions[1]. The department includes ten major operating administrations, such as the Federal Aviation Administration (FAA), Federal Highway Administration (FHWA), Federal Railroad Administration (FRA), and National Highway Traffic Safety Administration (NHTSA), each focusing on specific transportation modes and regulatory frameworks[1][7]. Key achievements include the implementation of the Bipartisan Infrastructure Law (2021), which enabled over 40 new programs addressing infrastructure modernization nationwide, from urban transit improvements to rural and Tribal region projects[5]. Under Secretary Pete Buttigieg’s leadership (2021–2025), the DOT expanded airline passenger rights, enhanced rail safety regulations following major derailments, and advanced national strategies to reduce roadway deaths, contributing to declining fatality rates[5]. The Department also played a crucial role in stabilizing supply chains during pandemic disruptions and increasing air traffic controller staffing to reduce cancellations[5]. Currently, the DOT manages a $117 billion budget (FY 2024) and continues to lead innovation in transportation technology, safety, and infrastructure resilience[4]. Its broad mandate includes fostering collaboration among federal, state, tribal, and local governments to achieve national transportation goals while considering environmental and defense priorities[1][2]. The DOT remains pivotal in shaping the future of US transportation, integrating advanced research, emerging technologies, and sustainability objectives[