New Jersey Gov. Chris Christie (R) has replaced his top official at the Port Authority of New York and New Jersey as questions about politics and lane closures on a key bridge continue to dog the potential 2016 presidential candidate.

Christie announced Friday that Bill Baroni, the deputy executive director of the port authority, has resigned. He has been replaced by Deborah Gramiccioni.

Baroni is the second top Port Authority official to resign in the past week.