Highway I-66 near Manassas in Virginia. (Stephanie K. Kuykendal/For The Washington Post)

Before diving into a thicket of transportation data and questions, a hefty new federal study makes a traffic projection that could get a chuckle, even from folks in Nebraska: Omaha, the new Los Angeles.

That’s by 2045, the study says, when traffic congestion in Omaha (current population of 435,353) could be just as bad as it is in L.A. (current population of 10 million).

The provocative prospect of gridlock in the heartland sets the stage for a 316-page document produced by the Transportation Department and released Monday by Secretary Anthony Foxx.

With Capitol Hill still in a rugby scrum over how to find fresh cash to pay for transportation, Foxx and his staff have spent almost 18 months compiling a futuristic look at how the nation will fare if the ways in which people and goods get from place to place evolve just as they did in the 20th century.

“We’ve been planning like it’s 1975,” Foxx said last month in an address at the Transportation Research Board’s annual convention. “In a real sense, our transportation system hasn’t caught up with the 21st century.”

The forecast in the DOT study is based on projected population growth (70 million people by 2045), increased growth in urbanized areas, lifestyle trends among millennials and baby boomers, and the impact of emerging technologies.

Mix those with current congestion, highway, port and aviation bottlenecks that stifle commerce, and an aging system, and the challenges of the next decades emerge.

“Let's just be honest,” Foxx told the TRB, “we’ve been moving from crisis to crisis.”

The study, which draws its data from scores of sources in government and the private sector, is the most comprehensive document of its type in recent years.

“This report will answer the argument that not addressing the [cost] is free. It’s not,” Foxx said in a recent interview. “Part of the purpose of doing a report like this is to get people to think about it before it happens.”

Foxx said he sees the report, titled “Beyond Traffic,” as an attempt to decouple the quest for long-term vision from the immediate politics and policy concerns of the present.

“It is important to note that Beyond Traffic is not an action plan and is not intended to be,” Foxx writes in an introduction. “It is a survey of where we are and where current trends may take us if left unaddressed.”

He suggests it is the beginning of a conversation and invited public comment.

In a nod to technology and the 21st century, Foxx eschewed the traditional Washington news conference to present the report, opting instead for a “fireside chat” in San Francisco with Google chairman Eric Schmidt for live broadcast on YouTube.

Although the study casts the future of transportation in gloomy terms, it suggests taking a holistic approach rather than addressing each system — highways, transit, aviation, shipping and pedestrian — as a separate entity.

“The potential is there to make a transportation system as amazing, frankly, as the stark scenario above is troubling — a system that is safer, more efficient, more sustainable, and more satisfying — one that successfully connects all Americans to the 21st century economy,” the report says.

Among the findings in the report:

●The country’s population will remain largely suburban given the current housing supply and infrastructure network in the suburbs.

●Urban areas will be larger and less dense.

● As the need to transport freight to large urban areas increases, conflict between freight and passenger traffic also may increase.

● Evolving technology will demand government flexibility. Regulations may be necessary in order to advance and encourage innovation, not to prevent it.

● Cars will continue to be a predominant mode of travel, but the rate of growth in vehicle miles traveled will increase more slowly than it has in the last 30 years.

●Transit may take on a larger overall share of commuting and local non-work travel, but cost and convenience will be paramount.

● Designing and retrofitting of roads to allow for safe passage of vehicles, bicycles and pedestrians will encourage multi-modal usage.

● Demand will increase for intercity transportation connections for people and goods.

● There will be increased need to upgrade and expand pipeline networks as oil and gas and other commodities are extracted far from ports and inland waterways.

The study concludes by saying that “there is a difference between having choices and making choices.”

“Our transportation network is the tie that literally binds our nation together,” the study says. “But it is aging and increasingly incapable of bearing the load our future demands. By knowing more about trends impacting upon our transportation system over the long term, we hope to make clear that current and future conditions will require greater coordination between levels of government and between government and the private sector.”