A D.C. streetcar in testing stops before the intersection of H Street and 3rd Street NE on Oct.16. The streetcars haven't yet started carrying passengers. (Evelyn Hockstein/For The Washington Post)

Just a couple of months before the promised opening of the first streetcar line in the District in half a century, basic questions remain unanswered. Among them: How much will the system impede other traffic? Will there be effective safety oversight? When will fares be collected? And when will service actually start?

On Wednesday, city officials reiterated their far-reaching vision of a streetcar network crisscrossing the city. But during test runs in recent weeks, the first cars on the city’s inaugural line, running east of Union Station, have snarled traffic and been in two minor accidents, a shaky start for a throwback mode of transportation that city officials are touting as an efficient means of moving people around the growing 21st-century metropolis.

(Related: D.C.’s streetcars in the The Post, then and now)

Three District mayors have backed plans to return streetcars to D.C. streets, following in the transit-oriented footsteps of Portland, Ore., and other cities. Officials in the nation’s capital want to build a 20-plus-mile network connecting neighborhoods from Georgetown and Takoma to Anacostia, linking richer and poorer communities, giving people an alternative to the automobile and, they argue, spurring development along the routes. Eventually they see a system stretching about 37 miles.

Their effort has been beset by years of delays, blown deadlines and questions about long-term funding. The inaugural 2.2-mile line, on H Street and Benning Road NE, is viewed by some as proof that the concept will work. Others see the opposite.

In the scramble to open the line, the District Department of Transportation has been sparring with safety officials and has failed to establish common rules of the road with the region’s largest transit provider, the Washington Metropolitan Area Transit Authority.

“One of our frustrations is there has not been a coordinated operating plan developed with DDOT that specifically informs each of the operators who has the right of way and what they should be doing,” said Jim Hamre, director of planning, scheduling and consumer facilities for Metrobus. “We’ve been reaching out for months and months. All we can do is treat them like other large objects moving down the streets. ”

Buses are facing significant delays behind the streetcars, which are making regular practice runs meant to simulate everyday operations. “We’re having to go around them. Since H Street has narrow lanes to begin with, it’s a challenge,” Hamre said. He said he has instructed bus drivers to pass streetcars only when they are stopped.

“That reduces the risk of misjudging,” Hamre said.

But it also forces faster-moving buses to hang back and wait for the less-agile streetcars, prolonging commutes for the much larger population of bus riders.

Back in 2010, District transportation officials estimated that 1,500 people a day will ride streetcars on the H Street/Benning Road line once it opens. But the X-line Metrobuses that travel the same streets — and go farther east and west — carry more than 12,000 passengers a day.

Mayor Vincent C. Gray (D) argued in an interview that such start-up issues will be resolved over time.

The D.C. Department of Transportation is training streetcar operators in traffic for the first time. The next stop? Passenger service. (Alice Li/The Washington Post)

“I don’t know that it hurts to slow people down in some instances,” Gray said. “We believe the streetcars will be a nice addition to the transportation modes in the city. And if there are wrinkles in it, we’ll work through those as we get into this.”

But the slowdowns are caused by problems with the line’s design, and solving that wrinkle would be a major undertaking.

At a key intersection east of Union Station, at Third and H streets NE, streetcars often stop and remain in the middle of the road for more than 40 seconds, despite having a green light. The pause is meant to allow the streetcars to safely change lanes. But it befuddles and annoys other commuters, who have to wait or try to veer around, creating a potential hazard.

One strategy would be to change the tracks’ alignment at that spot, and transportation officials said that’s possible as the H/Benning line is extended west toward Georgetown.

But the streetcar line’s extension is part of a broader debate about where the system should go next — and how much money should be directed toward the effort.

This year, the D.C. Council, led by Chairman Phil Mendelson (D), cut off a generous stream of automatic funding for future lines, though the council still voted to provide more than $700 million in planned streetcar-related funding through 2021. Gray remains sharply critical of the move, which essentially lopped planned funding in half.

A majority of council members have backed streetcar expansion, including two candidates for mayor, Muriel E. Bowser (D-Ward 4) and David A. Catania (I-At Large), as has independent candidate Carol Schwartz. The three mayoral candidates have offered some critiques, with Bowser assailing DDOT’s management, Catania voicing concerns over track layout, and Schwartz raising questions about the system’s costs and unsightly overhead wires.

Others have taken a harder line.

“It was ill-planned, ill-thought-out, ill-engineered, ill-everything,” said council member Marion Barry (D-Ward 8). “They plan to take it across K Street, and K Street is as busy as H Street.”

The tight quarters along H Street and Benning Road contributed to an Oct. 7 fender bender. DDOT said a vehicle’s mirror was protruding into a streetcar’s right of way and left a 40-foot “rub mark” on the streetcar. The vehicle’s driver was “cited for failing to maintain lane integrity.”

A week later, a streetcar experienced a “hit and run side swipe,” DDOT said. The streetcar’s mirror was broken.

On the plus side for the public’s pocketbooks — though not the city’s budget — plans to charge passengers are being delayed, according to internal city documents.

Early plans were to charge $1 or more a ride. But now “DDOT has determined that fares will not be collected at the start of revenue service,” according to a DDOT plan dated Oct. 2.

District officials said the move will solve a pair of outstanding problems: They don’t have a system in place to collect fares, and ridership is projected to be underwhelming.

Gray said the decision not to charge is a plus.

“It’s not a shortcoming,” Gray said, noting that for years a crucial section of the Portland system remained free. “It was designed to get people to use the streetcar system.”

It’s unclear how much revenue the city will forgo, adding to an extensive list of unresolved questions facing the fledgling program.

Other questions include: How will plans for a broader, billion-dollar-plus streetcar system — and its projected multimillion-dollar yearly deficit — be paid for in the long term? Will enough people ride the relatively short H Street/Benning line to make the system’s first leg worthwhile? Where else in the city will streetcars go eventually — and how long will that expansion take? And, ultimately, what difference will streetcars make in the lives of the city’s residents and visitors?

Even the question of when the first line might open remains unanswered. It has sparked a conflict between DDOT and the city’s State Safety Oversight Office, which is part of the city’s Fire and Emergency Medical Services Department.

District transportation officials have declined to provide a start date for streetcar service, other than to say it will come before year’s end. But the District informed the Federal Transit Administration that the streetcar project “is scheduled for revenue operations in the October/November 2014 timeframe,” according to an August letter from the FTA. An internal DDOT document notes a start date in “early November.” Nov. 8 was one internal target, two people working with the program said.

Before the beginning of “revenue operations” — which is industry lingo for streetcars actually carrying members of the public, whether or not they pay — transit operators generally go through a dry run called ­“pre-revenue operations.” It’s a dress rehearsal, a time when a last round of safety tests are completed and any remaining, unexpected problems are supposed to be found.

In September, the District announcedthat pre-revenue operations were starting. “You’re about to see a whole lot more of us: Pre-Revenue Operations begin Monday!” streetcar officials declared in a Twitter message Sept. 24.

But the Safety Oversight Office contends that DDOT forged ahead without the proper safety certifications. In comments this month, released under a Freedom of Information Act request, safety oversight officials asked DDOT for “an explanation of why ­pre-revenue activities have been scheduled prior to receiving approval from the [Safety Oversight Office] and the FTA.”

The review asked, “Where are the relevant Certificates that ensure the systems are safe and ready to commence” pre-revenue operations?

There have been intense, behind-the-scenes discussions in recent days involving DDOT, safety oversight authorities and other officials. DDOT officials have complained that safety office queries have at times seemed endless or nitpicky.

“Whenever you have a process like this, where you have one entity looking at another, there’s always going to be tension — as well it should be,” Gray said. “I think they felt they had met all the requirements and were ready to move forward,” he added of DDOT officials.

Gray said he raised DDOT’s concerns in a discussion with the deputy mayor overseeing public safety agencies. “I’m sure DDOT looks at it as one more hoop to jump through. But that’s what the state safety office is supposed to do,” Gray said.

This week, DDOT Director Matthew Brown pulled back from his department’s earlier proclamation about pre-revenue operations. Instead, he said the department is engaged in “simulated service.”

“There are some certifications that are required for pre-revenue operations. We’re working through those,” Brown said, citing checks on vehicle safety. “The system is up, substantially completed. We’re running. We’ve got to get through the safety certifications. So we’re working with FTA and FEMS to do that.”

Brown said that although DDOT had “internal targets” for launching the streetcar system, he is standing by only his public statements that the line will open to passengers by year’s end, after the department completes the necessary steps.

“We’re going to launch it when it’s safe to do so and we get through the safety certifications,” Brown said.