Cars, trucks, pedestrians and Streetcars share the road along H Street and Benning Rd., sometimes uneasily. (Katherine Frey/The Washington Post)

The District failed to install underground heaters at key points along its beleaguered streetcar line, allowing snow and ice to freeze up critical switches that are supposed to guide the 35-ton vehicles from one piece of track to another, according to a review by a panel of outside experts.

The decision, made during construction of the system years ago, has broad implications for the reliability of the 2.2-mile line running east of Union Station along H Street and Benning Road NE. During months of test runs last winter, the city’s red-and-gray streetcars were sometimes essentially left frozen in their tracks; workers had to dig out blockages by hand so the vehicles could pass.

The heaters somehow fell out of the plans for the line, according to a review of the project performed by industry executives that was released Thursday. The report points to the range of problems that have emerged in the system, which has been marked by years of delays and mismanagement.

District officials set a year-end target for opening the line to passengers. The project is now on its fourth mayor, and the public has still not been able to ride.

The industry group, organized by the American Public Transportation Association, listed numerous problems the system has faced, including: poor coordination among, and oversight of, contractors; shortcomings with the system’s design; and a variety of safety concerns. City officials have been working to address an initial list of findings for months, and the final report adds new details.

A key finding in the report, for example, is that no one in the District Department of Transportation had clear responsibility for the project.

“The senior manager, while well intentioned and focused on the job to be done, could be much more effective if supported with additional staff with rail transit experience to lead the project. DDOT will particularly benefit by hiring staff with direct light rail or streetcar operating, maintenance, or regulatory experience,” the report says.

“Without direct operational experience, it is difficult for DDOT staff to effectively analyze recommendations from contractors. This results in blurred lines of command and delays in decision making,” reviewers said.

The recommendations also say hiring a streetcar chief safety officer should be a priority.

City officials say they have hired a launch manager with streetcar experience and have put in place a key safety official.

The alignment of streetcar tracks very close to parked cars along H Street has gummed up traffic for cars and buses, and streetcars have collided with parked vehicles. The panel suggested that the potpourri of signs along the route has only deepened the confusion for those trying to park safely.

“While there are signs explaining the need for drivers to park inside the white line, with no tires on the line, these signs are small and posted only sporadically along H Street,” the report says. “Further, there is a profusion of other signs on that route — including ‘Tow Away Zone,’ ‘Emergency Snow Route,’ ‘Pay to Park,’ and ‘No Parking’ — so that the major message is essentially hidden.”

Another issue, also cited by officials from the Federal Transit Administration, concerns pedestrian safety. To thwart jaywalkers crossing the medians and streetcar tracks, the report suggests a host of possible deterrents, including landscaping, enforcement and fencing. But the group noted a possible backlash.

“While some communities welcome the prospect of increased safety in their neighborhoods by directing jaywalkers to crosswalks, others interpret any kind of fencing as a means of ‘dividing’ a neighborhood,” they wrote, noting that “should [the District Department of Transportation] decide to use fencing as a deterrent, it will be important to work collaboratively with local stakeholders to convey that safety is the motivating factor behind this suggested deterrence.”

The heater issue is emblematic of the dysfunction in the project.

“The installation of switch heaters is critical to minimize or eliminate disruption to the service during adverse weather conditions, especially when it snows. The snow can fall in between track switches that prevents them from functioning correctly,” according to the report. Having the heaters “would minimize labor hours that otherwise will have to be expended to clear snow/ice from switch areas.”

There was no clear description of why they weren’t installed. “We understand that switch heaters were part of the original design but then subsequently deleted. The Project team should revisit the issue and consider installing them,” the report said.

Mayor Muriel E. Bowser’s pick for DDOT director, Leif Dormsjo, brought in the APTA team earlier this year to provide a fresh look at the program. Bowser assigned him the task of getting the system opened safely.

Dormsjo said the heaters were cut from the project to save money.

“The previous management team value engineered that component out of the project,” Dormsjo said Thursday. “Value engineering is a process of looking for cost-cutting opportunities with a project that should not result in any lower level of quality — when done right. But when done wrong, it leads to situations like this.”

The heaters will now be put in.

“We accept that recommendation as a good finding and a worthwhile investment,” Dormsjo said, adding that it’s “another example of a corner being cut and us coming in with retrofits to get it right.” He said the streetcar team has been making progress on many of the recommended fixes.

Officials are coordinating with safety oversight officials on a schedule for opening. Dormsjo said it will be this year. “I’m talking months,” he said.