Commuters struggle with severe service disruptions at McPherson Square Metro station during a morning commute. (Astrid Riecken for The Washington Post)

By 2045, there could be an additional 1.3 million people living in the Washington region. Many will still depend on cars to get around, but a greater number will take advantage of a network of bike lanes, bus rapid transit systems and light-rail to help them get where they want to go as new developments spring up closer to public transit.

That is the future laid out in Visualize 2045, a blueprint for the region’s transportation future approved by members of the National Capital Region’s Transportation Planning Board on Wednesday.

The approval did not come without debate. Some board members said the plan focused too much on roadways and not enough on transit — continuing a long-standing debate about how to spend the region’s scarce transportation dollars.

Others, including Falls Church Vice Mayor David Snyder, said the document failed to take into consideration how new technologies are changing the way people get around.

“We need to focus on ops provided by new tech that get us past the old fight between transit and roads,” Snyder said.

D.C. Council member Charles Allen, who chairs the Transportation Planning Board, acknowledged that there were disagreements but said the document moves the region in the right direction and represents a step forward.

“These plans are not etched in stone,” he said. “They are living documents.”

The region’s leaders are preparing for a future that, according to forecasts, will include more than 3 million additional trips per day. While many of those trips may still be by car, many of the projects in the plan are designed to push commuters to other modes of transportation, including transit, biking and walking. Planners have long maintained that the region must look at a variety of solutions for solving the region’s gridlock.

The document includes two parts. One is an inventory of the possible — a list of more than 600 highway and transit projects for which officials think there is enough money. Think Maryland’s light-rail Purple Line and phase 2 of the Silver Line, which will extend Metro to Dulles International Airport and into eastern Loudoun County. In all, those projects will add about 1,400 new lane miles of roadway to the region’s highways — 460 of which will be toll lanes. The plan also calls for expanding both Metro and commuter rail service. In addition, the region would add five new Bus Rapid Transit segments in Montgomery County and light-rail systems around the region. Total cost for the projects is estimated at $291 billion.

Congestion will still probably worsen, but building the projects listed in the plan will ease some of the pain, officials said.

During the peak of the morning commute, 11 percent of lane miles in the region are congested. By 2045, that number will grow to 14 percent. Translated: Approximately 800 more lane miles will be congested in the morning — an increase of 43 percent from today.

The second list is of seven “aspirational” elements — initiatives that officials would like to see in place but lack the funding to guarantee they will happen. Included among those: a second Metro station at Rosslyn that would be part of a new inner loop on the Metro system, connecting Virginia with Georgetown and Union Station. Another idea: creating a “beltway” for bicycles by adding more than 20 miles to a network of trails dubbed the National Capital Trail. As a bonus, the trail would connect bike commuters to dozens of rail stations.

The plan also acknowledges that new developments might change how they view the future of transportation in the region.

Technological advances, however, make some aspects of future travel difficult to predict, as certain innovations offer the potential to completely redefine travel throughout the country and region. One such innovation that appears to be just over the horizon is the introduction of autonomous vehicles onto the region’s roadways. Though the degree and pace of adoption is still unknown, these vehicles have the potential to completely revolutionize the private and for-hire vehicle markets and vehicle ownership, and ultimately shift land-use patterns if they reduce some of the drawbacks of long-range commutes.

Visualize 2045

Visualize 2045 is required by the federal government, but is used by local planners to outline how they will tackle traffic in the region. And while the TPB does not fund or have final say on the individual projects in the plan, it brings together jurisdictions and encourages them to see beyond their borders and understand how decisions they make affect the system as a whole.

TPB includes elected leaders from 23 cities and counties, as well as representatives from Maryland, Virginia and the District, the Washington Metropolitan Area Transit Authority and other bodies.

Clarification: This post has been updated to clarify that population projections indicated there could be an additional 1.3 million people living in the region by 2045.