American River Taxi owner, Shaun Guevarra, walks onto his vessel before it departs from Gangplank Marina to Washington Harbour. (Matt McClain/THE WASHINGTON POST)

Hot coffee. Check. Gas. Check.

On a bright and sunny Wednesday morning, Washington’s newest water taxi commuter service was ready to go.

There was just one thing missing: commuters.

For decades, regional leaders and private entrepreneurs have dreamed of harnessing the Potomac River to relieve congested highways. But despite hundreds of thousands of dollars spent on studies, a network of ferries and water taxis that quickly deliver commuters from their homes to their workplaces has yet to materialize. But that might be changing.

American River Taxi is the latest company to attempt to lure Washington area residents out of their cars, off Metro and onto the water. After months of shuttling baseball fans from Georgetown to Nationals Park, meeting area residents and researching the market, the company decided to enter the commuting game. In April, it launched an early morning water taxi service to shuttle workers from the Southwest waterfront to Georgetown.

For $8 each way, American River Taxi whisked commuters from the waterfront to Washington Harbour. The 30-minute ride was billed as a pleasant, relaxing alternative that would take commuters around Hains Point and Reagan National Airport and past several major roadways where passengers could see lines of cars idling in traffic. The boat, painted bright taxi yellow, can accommodate 24 commuters.

But the company is struggling to make the service work. Commuters say that while they love the concept, they’re not quite ready to make the switch.

“It was relaxing, and I was in a fantastic mood when I got to work,” said Jennifer Druliner, one of American River Taxi’s first customers. But, ultimately, Druliner, who works at the U.S. Green Building Council, said the water taxi wasn’t practical because it was about four times as expensive as Metro and took too much time.

That, transportation planners say, will be a challenge for companies with hopes of using the river as a commute route.

“It’s easy for people to say they’d take it, but then they have to figure out the logistics — how they’ll get to the ferry and how they’ll get from the ferry to work,” said Katherine Graham, a transportation engineer with the Virginia Department of Transportation.

Ron Kirby, director of transportation planning for the Metropolitan Washington Council of Governments, said regional leaders have talked about using the Potomac as a commuter route for decades but have never been able to make it happen.

“It’s kind of an obvious thing to look at, because [the Potomac’s] there and there are other places that have ferry services,” Kirby said. “But when people start looking at the details — that’s when reality starts to set in.”

A 2009 study, funded by the Virginia Department of Transportation, estimated that it would cost nearly $30 million to make the necessary capital improvements for a Woodbridge-to-D.C. route and about $20 million for improvements for service that would run between Virginia and Maryland. Then there’s the question of whether people would use such a system and whether fares could be priced to compete with other modes of transit, Kirby said.

Officials might soon have those answers. Prince William County Supervisor Frank J. Principi (D-Woodbridge), an enthusiastic backer of ferry service, is part of a new group of regional leaders working with the Northern Virginia Regional Commission to study the viability of a ferry system. After a series of test trips in 2009 to gauge travel times, Principi said, the new group decided to commission a study to determine whether there is enough demand.

Kirby said the key to building a Potomac-based transportation system, at least initially, might be to focus on other types of users, as Potomac Riverboat Co. has: tourists and residents looking for weekend fun.

“We have a tendency to focus on commuting because that’s the first thing we want to tackle, but commuting is only 20 percent of the trips” people take, he said.

Kirby might be on to something.

Willem Polak, president of Potomac Riverboat Co., has built a successful business that offers water taxi service between National Harbor and Alexandria and on several other routes along the Potomac. The service is geared toward the leisure, business traveler and tourist market. Lately, though, Polak, who is part of the Northern Virginia group looking into expanding commuter offerings, said he has noticed that a growing number of commuters are riding his boats, which is why he thinks there’s a market for the service.

Despite quietly suspending its early morning service at the end of May, American River Taxi is hopeful that the Potomac can become a viable route, said Shaun Guevarra, the company’s president. He said the company plans to retool its efforts to make the service work.

“It’s really about changing people’s mind-set, getting them to think about the water,” Guevarra said.