Calling passenger safety the “number-one priority,” D.C. Mayor Muriel E. Bowser’s new transportation chief, Leif A. Dormsjo, on Friday backed away from a pledge by his predecessors to open a long-delayed streetcar line next week.

Bowser (D) “wants to get it right, not just get it open. That’s a different mandate from the previous administration,” Dormsjo said. “There was a lot of pressure to get it open. It’s not my place to evaluate why that was. But I’m under a different charge, and that charge is to get it right.”

Dormsjo said he is also reconsidering the business plan put forth by the administration of former mayor Vincent C. Gray (D) for the streetcar, which would have been free to passengers for an extended period. Dormsjo is bringing in industry experts to review operation plans more broadly, he said.

Dormsjo said the first person he called when he came into office Jan. 2 was the head of the D.C. State Safety Oversight Office, Capt. Kelton Ellerbe.

Internal e-mails showed deep tensions between the D.C. Department of Transportation and the SSOO after the Gray administration sought to push ahead with a final series of dry runs, known as pre-revenue operations, without completing all safety certifications. The Federal Transit Administration also raised significant concerns about safety issues and timing in December.

“In the past there had been some finger-pointing,” said Dormsjo, DDOT’s acting director. “I pledged to him we would have a strong relationship. If it took two weeks or two months or two years for him to do his work, he was going to have cooperation from this department.”

The safety certification process is “iterative,” with documents and reports under review and DDOT responding to additional queries, Dormsjo said. He would not offer any time estimates.

“We will set no arbitrary deadlines for the independent state safety office,” Dormsjo said. “You can’t give yourself a first down.”

Dormsjo said he will bring “stronger management discipline” to the program.

When he came in, he asked who was in charge of the streetcar program “and five people raised their hand.” The good part of that is the enthusiasm, he said. “The bad thing is, you can’t run a project with five people in charge. You’ve got to have one person in charge.”

Longtime project official Ralph Burns was tapped for the task, Dormsjo said, and no one was fired or removed. Dormsjo considers himself the “project executive” and said he meets frequently with DDOT streetcar officials and outside contractors to oversee the effort.