Preparations begin for the unveiling of the DC Streetcar line. (Keith Lane/For The Washington Post)

The D.C. streetcar deserves a round of applause.

Not because it’s finally rolling, returning last month after 50 years, but because it shows a commitment to transit that will keep the District among the nation’s great cities. And early ridership numbers are promising.

As millennials — those people born between the early to mid-1980s and 2004 — come of age, they’re deciding in huge numbers to live, work and play in urban areas. Pew Research Center reports that 38 percent of 18- to 29-year-olds prefer to live in cities, compared with 24 percent of all other age groups.

And they’re ditching cars and choosing public transit, ride-hailing services, bikes or a good pair of shoes over car ownership, insurance and maintenance costs.

But it’s not just the young folks. Pew reports that boomers also prefer city living. As people get older, cities offer more convenient amenities, healthy and walkable communities and cultural pursuits not available in the ’burbs.

Cities that want to continue growing and prospering are taking steps now to meet the needs of these massive generational waves. Core to their success is a robust, multimodal transportation network that facilitates mobility.

In the District and in many other forward-thinking cities nationwide, this network includes streetcars.

Why streetcars?

They power economic development in ways bus routes cannot.

Fixed rails involve a bigger commitment than bus routes. The greater investment and ongoing maintenance that a streetcar line demands signal a long-term promise that attracts businesses and developers. Portland’s streetcar line delivered millions of dollars in development adjacent to its route. Kansas City, Mo., attracted at least 11 commercial and 21 residential developments along its starter line.

All of these developments generate tax revenue for municipal coffers.

Plus, moving more people translates into fewer people driving, reducing pollution and congestion. Electric-powered streetcars are zero-emission machines. They’re also quiet, bike- and stroller-friendly and won’t splash pedestrians on sidewalks when it rains.

Most important, streetcars provide connections to the larger transit network for more people.

The 2.2-mile starter line of the D.C. streetcar on H Street and Benning Road NE provides another option for residents and visitors in Northeast to get where they’re going.

And this is just a starter line.

As the streetcar finds success in the District, just as streetcars have in other cities nationwide, the number of routes will grow and the network will lengthen. Longer routes will drive additional investment and provide additional transit options to more of the District, complementing existing bus and Metro routes, ride-hailing services and bike lanes.

An important next step for the District is integrating fares so that streetcar tickets can transfer to bus and Metro services across the region. Planners are working on this.

The times are changing. Younger Americans prefer city living and no longer dream of owning cars. Older citizens, too, want the convenience and amenities of urban areas. We all want less congestion on our roadways and less pollution in the air. Multimodal transportation is key to meeting these demands.

The D.C. streetcar, now operational after a long journey, enhances multimodal transportation in the District, putting the city on track to grow and prosper as demographic waves break across the country in the coming decades.

The writer is vice president of HNTB, an architecture, engineering, planning and construction-services company.