James Simpson has confirmed reports he is stepping down in June as commissioner of New Jersey's Department of Transportation and returning to the private sector.

James S. Simpson, commissioner of New Jersey's Department of Transportation, talks about the loss of structural integrity of the rusted-through webbing of a support I-beam under the road surface of the Pulaski Skyway (AP Photo/Mel Evans)

He called his time as Commissioner, in which he headed the boards of NJ Transit, the New Jersey Turnpike Authority, the South Jersey Transportation Authority and the state Transportation Trust Fund, "the most gratifying experience I've ever had."

Simpson said he had wanted to leave last fall but decided stay for the start of the Pulaski Skyway project and management changes at NJ Transit and the Turnpike Authority.