Deputy Transportation Secretary John Porcari is stepping down after four and a half years of service.

In a message to DOT employees, Secretary Anthony Foxx thanked Porcari and said he has asked Federal Highway Administrator Victor Mendez to step in as Acting Deputy Secretary starting Jan. 1.

Porcari led the Department’s effort to streamline the infrastructure project approval process and cut red tape, major initiatives of the last highway bill. He also increased enforcement of the Buy America program, Foxx said.

“Through these programs and so many others, John is leaving the Department and the Nation’s transportation system stronger than when he started,” Foxx said in his message.

“Both (former Transportation) Secretary (Ray) LaHood and I have benefited from having him by our sides at every step of the way.”

As head of the Maryland Department of Transportation before taking the DOT job in June 2009, Porcari helped plan the rebuilding of the Woodrow Wilson Bridge across the Potomac River on I-95.

Mendez has been FHWA Administrator since 2009. Before then he was with the Arizona DOT and served as President of the Western Association of State Highway and Transportation Officials, and the American Association of State Highway and Transportation Officials.