Muriel E. Bowser, David A. Catania and Carol Schwartz prepare to take part in a debate at NBC4 on Oct. 15. (Matt McClain/The Washington Post)

There was one moment during a Sept. 18 debate, when the three D.C. mayoral candidates talked about what form of transportation they would use if they had no access to a car, that became a rare public discussion of an issue affecting all city residents: transportation.

In subsequent public debates, there was little to no mention of the District’s deteriorating roads and bridges, Metro disruptions, crowded streets or the troubled streetcar project. On one occasion, time ran out before the candidates could address transit accessibility.

The city’s aging transportation system took a back seat during the campaign.But when the new mayor takes office in January, he or she will encounter the critical problems of a rapidly growing and changing city that demands more transit and better road infrastructure.

“We have a real opportunity to do some very smart things with transportation, but we are going to need the leadership of a mayor that is going to look expansively,” said Nancy J. MacWood, a longtime D.C. resident and chairwoman of the Committee of 100 on the Federal City, which advocates for historic preservation and serves as a watchdog on transportation issues. “So far it is unclear to us that they all recognize that as mayor, they need to focus on transportation.”

All three major candidates— D.C. Council members Muriel E. Bowser (D-Ward 4) and David A. Catania (I-At Large) and former council member Carol Schwartz, an independent — have agreed that biking, mass transit and multiple forms of mobility are important to the District’s future. They have hinted their support for some of the current administration’s policies, including improvements for cyclists and pedestrians, expanding bus service and the new MoveDC plan, a 25-year vision for city transportation that advocates have praised as progressive.

Looking at where key candidates stand on pressing issues facing Washington.

Some residents and leaders say that with MoveDC in hand — a proposal crafted with public input — the next mayor should be able to move quickly from planning to implementation.

“We are at a point where a lot of the details that had to be done to figure out how we are going to move forward have been done. So the next mayor doesn’t have to do that backfilling of planning and details, and he or she can just move forward with this comprehensive approach,” said Shane Farthing, executive director of the Washington Area Bicyclist Association.

But the ambitious plan comes with a $54 billion price tag, and advocates say it needs a mayor’s political will to get it funded and rolling.

If the plan is embraced by the next mayor, the city could be on its way to having a wider transit network that includes a 22-mile streetcar system, dedicated bus lanes on major commuter corridors, expanded Metrorail service downtown, a water-taxi system and 200 miles of on-street bicycle facilities.

But activists and some residents complain that the candidates have failed to elaborate on their priorities and to offer solutions to critical problems such as parking woes, the recent Inspector General’s report criticizing the city’s unequal and sometimes arbitrary enforcement of parking and traffic rules, and the need to expand rail service and find a fixed funding source for Metro.

“They have shied away from outlining their transportation priorities and their capital improvement vision,” said John B. Townsend II of AAA Mid-Atlantic.

The city’s deteriorating infrastructure is a concern for drivers and other road users who encounter potholes and rough pavement that can cause damage. City drivers collectively pay $311 million a year in extra vehicle repairs and operating costs —or $833 per motorist, according to the American Society of Civil Engineers.

Nearly 40 percent of the District’s roads are in poor or very poor condition, according to the D.C. Department of Transportation. Lack of funding has resulted in poor maintenance and slow response in road repairs, officials said.

According to the ASCE report, 30 of the 239 bridges in the District are considered structurally deficient, and 155 bridges are functionally obsolete, which means they do not meet current standards. DDOT officials said last month that they have a plan for the bridges considered to be structurally deficient. Over the next two years, to advance the MoveDC initiative, DDOT plans to begin replacing the Frederick Douglass Memorial Bridge over the Anacostia River and improving other key bridges.

“It is unacceptable to have a city that is the capital of the free world to have roads in the condition that they are in the District,” Townsend said. “We have been dodging the bullet for years. We have to look at maintaining what we have, and for safety’s sake, take care of our bridges, too.”

Schwartz, the independent candidate, has proposed reinstating a fund for potholes and street and sidewalk repair. She said she would place greater emphasis on maintaining existing infrastructure.

“I would work to ensure that our roads are never in need of repair, mass transit is affordable and reaches all corners of the city, and there is a comprehensive network of bike lanes that allow cyclists to move about the city safely,” Schwartz said in response to a recent survey by the Committee of 100.

Bowser and Catania have said they would ensure that DDOT is more responsive in maintaining city roads, and that a plan is in place to replace roads, bridges and sidewalks.

Regional transportation experts say that as the city grows and adds jobs —170,000 new residents and 200,000 new jobs are projected for the District in the next 25 years — demand for transit, parking and roads also will increase, and the next leader will have to address those needs.

Road improvements are viewed as critical not only for drivers but also the growing number of cyclists. All three candidates say they support adding bike facilities, but advocates say they hope the next mayor goes a step further and focuses on providing more bike lanes and better and more equitable traffic enforcement. About 15,000 D.C. residents, or about 4.5 percent of working residents, commute by bicycle, according to census data. The number has more than doubled in five years.

“The next mayor will have to figure out what pace they can move forward in things like bike lanes and bus lanes,” said David Alpert, founder and editor of Greater Greater Washington. The test, he said, will be in pushing for projects that create tensions among the various users, such as adding bike lanes in front of churches or bus lanes that would take away roadway from the general traffic.

“Are they willing to push ahead projects like that where there’s some controversy?” he said. “We don’t know if they are.”

One thing the candidates have agreed on is that safety should be the top priority for all road users. Catania says he supports a public campaign that focuses on safety and certain core values to encourage a system where bicyclists, pedestrians and drivers all use the public space safely and conscientiously.

Bowser has promised to get the District to adopt a “Vision Zero” pledge, which promotes a transportation network that is safe for drivers, cyclists and pedestrians with a goal of reducing serious injuries and fatalities on the road.

Some residents and advocates say the next mayor should push D.C. police Chief Cathy L. Lanier to reinstate a traffic enforcement unit, with trained officers who would equitably enforce traffic rules for drivers, cyclists and pedestrians.

“We are the only major city that doesn’t have a dedicated set of transportation- enforcement officers in the police department and whose jobs is really to go out and push these things forward,” Farthing said. “I want the police out there watching for unsafe behavior.”

That idea hasn’t been widely mentioned in the campaign, unlike parking and the D.C. streetcar system.

On parking, Schwartz says she does not support a policy that reduces or eliminates minimum parking requirements for private developments. Bowser said she would appoint a parking czar and create a comprehensive parking plan.

“The parking needs of each neighborhood vary greatly such that a one-size-fits-all policy does not necessarily make sense,” Bowser said in response to the Committee of 100 survey. “New development should not exacerbate demands on existing public parking. On the other hand, requiring unnecessary parking can increase the cost of housing and prevent other desirable uses and amenities. In short, a balance must be struck. Parking generally must be considered in a more thoughtful and comprehensive manner.”

Catania says he would focus on revamping the transportation system, including adding bus and bike lanes so that residents and commuters have options, and traffic can be reduced along with the need for parking.

As for the city’s troubled streetcar project, Catania and Bowser say they are strong supporters of the system as a means of moving people around the city and promoting economic development. But neither has pledged to support restoring funding that was rolled back in this year’s budget.

“It’s important we get the H Street line running and connected, and learn some lessons and make decisions about how we move forward with the larger proposal that’s on the table,” Bowser said during an Oct. 13 online chat with Greater Greater Washington. “Are we completely sure about all of the lines on the table? It bears some discussion.”

Catania says he would fully construct the system and will seek to build both east-west and north-south lines.

Schwartz said she is open to building a few lines, particularly adding a line that goes over the Anacostia River. But she said she opposes a wide network of streetcar lines and instead would invest in growing Metrobus’s fleet to increase rider capacity.

“I am not convinced the investment into a fleet of streetcars — not to mention the disruption of tearing up our city streets (which in itself has a huge actual cost as well cost in loss of productivity) — will ultimately give the District a return on investment,” Schwartz said in response to the Committee of 100 survey.