Federal Highway Administration (FHWA) is an agency within the United States Department of Transportation. The agency provides billions of dollars in federal aid annually to the states to fund highway research, planning, design, and construction. It coordinates highways with public transit and rail and air travel to achieve the most effective balance of transportation systems and facilities. The FHWA works to improve the total operation and safety of the nation's highway systems. It also works to lessen the environmental impact of highways and regulates truck and bus travel.