John Claflin's departure from TTA was described by officials as a mutual agreement between Claflin and TTA's Board of Trustees.
"In light of the Triangle Regional Rail Project's recent shift in direction, I feel that this is the appropriate time to appoint new leadership to pursue TTA's mission," Claflin said in a statement.
TTA officials said last month that the agency would no longer seek federal funding for the regional rail project because it's too difficult to meet funding requirements without sacrificing the value of the project. Officials said the TTA would work directly with the community to create a transit system that meets Triangle needs and look for more local financial support.
The agency wants to build a 28-mile rail system that would connect Raleigh, Cary, Research Triangle Park and Durham. The project is expected to cost about $800 million.
"We extend our sincere thanks to John for his hard work and dedicated service over the past four years," TTA Chairman Carter Worthy said. "Under John's guidance, TTA's regional bus service has achieved record ridership, and ride-matching and van-pooling have enjoyed unprecedented success. We are eager to build upon the strong platform that is in place to enhance the network of transportation options in the Triangle."
Claflin joined TTA in 2002. He previously worked for Denver's Regional Transportation District as assistant general manager and chief operations officer.
Wib Gulley, TTA's general counsel, and Saundra Freeman, the director of finance and administrative services, will divide the general manager's responsibilities while a search is conducted for an interim replacement, officials said.