Inner-loop evening traffic just south of the Baltimore-Washington Parkway. (Mark Gail/The Washington Post)

Ted Leonsis is chief executive of Monumental Sports & Entertainment, which owns the Capital One Arena in Washington, the Capitals, Wizards and Mystics and the AFL teams the Valor and the Brigade, and is a member of the Greater Washington Partnership.

The good news is that millennials are interested in the Washington area. The bad news is that we're not keeping up with other regions, and too many talented workers are leaving. It's more essential now than ever to keep the caliber of people we have and to attract the best and brightest from around the country, even the world.

To compete, the Washington area must evolve into a "supercity" to put us on par with other large metropolitan regions, such as those centered in New York, Los Angeles and Chicago.

To our north, Baltimore has long been merging into the greater Washington area. Just consider the three major international airports serving the region. Baltimore-Washington International Marshall Airport is the busiest, serving a record 25.1 million passengers in 2016, compared with Reagan National Airport's 23.6 million passengers and the 21.8 million passengers flying through Washington Dulles International Airport. I fly out of BWI just as often as I do the others.

And on land, soon you may be able to travel the 40 miles between these two cities in just 15 minutes. Maryland Gov. Larry Hogan (R) has pushed plans to build a high-speed maglev rail that can get passengers from Baltimore to Washington in the time it takes to drive from Capitol Hill to Capital One Arena — on a good day.

To the south, we're increasingly sharing our workforce. Between 2000 and 2013, daily commuters from Richmond to Washington have increased 69 percent; conversely, commuting from Washington to Richmond has increased 25 percent. Richmond is sending more than 10,000 daily commuters to Washington. The Virginia Department of Rail and Public Transportation's recently announced plan for more tracks to bring faster, more frequent Amtrak and Virginia Railway Express service between the two cities, meaning even more workforce-sharing in the future.

Entrepreneurship communities are also booming well beyond Silicon Valley, as Entrepreneur magazine recently credited Baltimore for its impressive list of start-ups and boasted of Richmond's plans to bring in more creative and tech industries.

The Baltimore-Washington-Richmond supercity isn't just an idea; it's a necessity to keep our economies strong. Despite obvious gains for these cities individually in recent years, economic growth for the region is expected to lag similar regions in the next five years.

That's why I joined other leaders in the region to launch the collaborative Greater Washington Partnership, a team of civic-minded chief executives committed to keeping this supercity one of the world's best places to live, work, innovate and build a business.

Recently, we unveiled an initiative to find solutions that will make the region an even bigger economic engine. And one major principle is a first-of-its-kind regional mobility blueprint that blurs the line between states and cities. We will show what this future supercity already has in terms of transportation and what is needed in the near future to maintain healthy growth.

Together, we’re working to promote forward-thinking ideas, starting with a focus on improving our clogged transportation network and building a workforce with the skills needed for the economy of the future. We’re working to share vital resources and elevate our region as a vibrant hub for business.

We are the third-largest regional economy in the United States and seventh-largest in the world. This is a global capital, among the most powerful, wealthy and generous communities in the world. We are a top-10 tourist destination with many universities and research institutions and a vibrant economy. Our region also boasts a thriving cultural scene and well-educated workforce.

Businesses coming to the area will want access to it all.

We have the building blocks for success. Now it’s time to start putting them all together.