Correction: An earlier version of this story gave an incorrect number for passengers transported by water taxi between National Harbor and Alexandria annually. The water taxi carries more than 130,000 people a year. This version has been corrected.

There is a proposal to add a cable car to ferry passengers from Rosslyn to Georgetown over the Francis Scott Key Bridge. (Nikki Kahn/The Washington Post)

How about a high-speed ferry to transport commuters from Woodbridge to the D.C. waterfront in under an hour? Or a gondola to carry people through the skies over Rosslyn to Georgetown in less than five minutes? A superfast train that could take you from Union Station in Northeast Washington to Baltimore in 15 minutes and another that would get you to Richmond in 90 — more than an hour faster than today’s Amtrak service?

Sound too unrealistic for a region that struggles with upgrading its crumbling bridges, paying for new roads and finding the money to rebuild its struggling Metro system? Possibly. But transit planners, advocates and government officials say the proposals aren’t just wishful thinking.

“Some people say given Metro’s needs why should we do that? Well, we’ve got to be able to walk and chew gum at the same time,” said Rep. Gerald E. Connolly (D-Va.). “We can maintain the infrastructure we’ve got while also looking at the future in terms of what our needs are and how they might be best met.”

The Washington region consistently ranks near the top for having some of the worst traffic in the country. In 2014, residents spent an estimated 82 hours stuck in traffic — up from 74 hours in 2010, according to the Texas A&M Transportation Institute.

American River Taxi owner, Shaun Guevarra, walks onto his vessel before it departs from Gangplank Marina to Washington Harbour. The taxi has been offering commuter services since April 2011. (2011 photo by Matt McClain/FOR THE WASHINGTON POST)

The region also is projected to add more than 1.5 million people and 1 million jobs by 2045, according to a report by the Metropolitan Washington Council of Governments, worsening congestion.

Separate studies are underway to determine the feasibility or next steps for projects such as the commuter ferry and the gondola to provide relief.

“We need to look at making every transportation option available,” said Kanti Srikanth, director of transportation planning at COG. “If it works out, great. We can provide one more option.”

The first six months of Metro’s SafeTrack rebuilding program have shown the importance of having options.

Telecommuting and the integration of bike- and ride-sharing and buses have helped riders navigate the Metro disruptions. So why not explore commuter ferries, cable cars and bullet trains for the future, proponents ask?

Studying the proposals doesn’t mean they will materialize or that they will happen overnight, Srikanth said. It was about half a century between the time Metro’s Silver Line was proposed in a federal document and the 2014 opening of the line’s first five new stations.

Prince William County Supervisor Frank J. Principi has been pushing to bring commuter ferries to Washington’s waterways for over a decade.

In this file photo, a trial commuter ferry service for Prince William County stops in Old Town Alexandria. (Tracy A. Woodward/The Washington Post)

The project was recently awarded a $174,000 federal grant for an environmental impact study.

Principi (D-Woodbridge) said a market exists for fast ferry service between Alexandria and the District. Eventually, as areas along the Potomac River continue to develop, Principi envisions a wider system, accessed by bus, bike or rail, where commuters would pay fares with their Metro SmarTrip card, and with routes as far as the Occoquan in Woodbridge to the Washington Navy Yard.

“I see no reason why we can’t have fast ferry service here in our own region. It’s just a matter of time,” Principi said. He said the project could come to fruition within five years.

Ferries are heavily used in harbor cities such as New York, San Francisco and Seattle. New York City, for example, recently announced plans to expand its ferry system to connect communities not served by the subway in Queens, Brooklyn and the Bronx to work centers in Lower Manhattan.

But in Washington, aside from some river taxi service mostly used by tourists, the concept of a commuter ferry has been largely unexplored.

“It’s too bad because the water is a great way to get around,” National Harbor developer Jon Peterson said in an interview earlier this year. “It is a great alternative. Every major city uses their waters.”

The water taxi that connects National Harbor to Alexandria has been successful, carrying more than 130,000 people a year, according to the Potomac Riverboat Company. But the 20-minute, $7 ride isn’t appealing to commuters. Washington’s speed and noise restrictions on the Potomac also present a challenge in running a successful commuter ferry, Peterson said.

Principi said speed waivers would be granted once a plan is approved.

The proposed transit system, under study by the Northern Virginia Regional Commission, still faces questions and hurdles. As with other major transportation endeavors, funding remains the key challenge.

Operating a ferry route from Alexandria to the District could cost nearly $6 million. According to a market feasibility report last year, with as many as 2,000 trips per day, the route is commercially viable.

Although there is no estimate of how much it would cost to build docks and access points, a major hurdle, according to one study, would be addressing stakeholders’ concerns “about adding another mode to the mix of decisions on existing highway and transit infrastructure maintenance needs as well as already planned and underway transportation infrastructure expansions [that] may cause even more ‘fog’ in the funding equation.”

Still, some supporters say a ferry system would be cheaper and easier than investing in underground tunnels to expand Metro. The Silver Line extension, the first phase of which opened two years ago, cost $5.8 billion. Adding an infill station in Alexandria’s Potomac Yard community is expected to cost $268 million.

By comparison, building a gondola over the Potomac connecting Rosslyn and Georgetown would cost $80 million to $90 million, according to a feasibility study released last week. The annual operating cost would be about $3.25 million.

The cable-propelled transit system has potential to allow people to travel more quickly between Washington and Virginia, and serve at least 6,500 passengers a day, the report says.

“This is something that could be done,” said D.C. Council member Mary M. Cheh (D-Ward 3). Cheh, who chairs the council’s transportation committee, helped secure $35,000 in the city’s budget to fund a gondola feasibility study.

“Given that it has great advantages for easing some transportation snags and revitalizing the Georgetown area, which doesn’t have a subway, I am kind of keen to seeing what the steps are to implement it,” Cheh said.

Other ideas appear more out of reach. Building a 40-mile high-speed magnetic-levitation, or maglev, train system that could carry passengers between Washington and Baltimore in 15 minutes would cost at least $10 billion, according to estimates.

Still, a critical step was taken last year when the U.S. Transportation Department awarded nearly $28 million to conduct studies on building the high-speed rail line. The funds support ­private-sector efforts to bring maglev trains to the region as part of a larger vision for building such a system along the Northeast Corridor.

In the plan to speed up rail service along the 123-mile stretch between Washington and Richmond by 2025, some investments, include adding a third track, are already underway. Cutting down travel time between the two capital cities from the current 2 hours and 45 minutes to 90 minutes would make train travel more attractive to travelers in the corridor

In the mix of ideas, some officials say, should be plans to continue broadening the bicycle infrastructure and extending Metro to unreached areas, such as Prince William.

Connolly says he is interested in investments that will have big payoffs.

“I say let a thousand flowers bloom and see what works,” Connolly said. “I don’t want to discourage imagination or alternatives. But once we go through it in a methodical way, the feasibility and the initial engineering processes, we will have a better idea of what’s practical and what’s not. But let’s not rule out a lot of things in advance.”