Metro Atlanta and Washington have much in common. The population is the same (about 5.7 million); each is a capital; each experienced most of its growth in the late 20th century; and each has southern roots, but has experienced population influx from the North.

The two metro areas also share a crucial 1970s transportation investment: a federally funded heavy rail system.

Atlanta lobbied hard for MARTA because one thing Atlanta understands is the importance of transportation. Why is this important? Transportation drives economic development. This is why we have the Georgia Department of Transportation but no Georgia Department of Sewers, Water or Broadband.

At one point Atlanta was named Terminus, based on the railroads that put the city on the map. Highways followed and then the world’s busiest airport. These were intentional investments, creating the business capital of the New South.

Unfortunately, we have woefully under-invested in MARTA since the beginning and it shows in the economic development comparison with Washington.

There is a sideshow on a website that tracks the evolution of Metro, D.C.’s version of MARTA: http://greatergreaterwashington.org/post/4835/the-evolution-of-metrorail-1976-2010. Each click shows new expansion during the past 35 years; it takes 26 clicks to see its growth through 2010.

There is no comparable website for MARTA, but it probably would take only five or six clicks.

Why should anyone care? Because we have missed out on tens of billions of dollars in new development that would have been infinitely more sustainable economically, fiscally, environmentally and socially, and which, if pursued now, can pull Atlanta out of the economic ditch.

Metro Washington only had two economically important walkable places 25 years ago as the then-new Metro system was gaining traction.

Today there are 23, with another 14 evolving. Downtown Washington is approaching build-out with the final project just starting construction. The greater downtown, which includes eight places akin to Atlanta’s Midtown, is projected to be built out in 10-15 years.

Plus, more than 70 percent of the walkable, rail-served development is taking place in the suburbs. It is more about the transformation of the suburbs than redevelopment of the city.

Now some may think, “Yes, but the federal government is in D.C., so the comparison to Atlanta doesn’t apply.” We have heard a rumor that the Federal government was in D.C. 25 years ago when very little walk-able development existed. The ever-expanding rail system, along with proper zoning and enlightened developers, made it happen.

It is time for metro Atlanta to recognize that expansion of transit, including MARTA, commuter rail and the Beltline, is crucial to the region’s economic future. It is the most important infrastructure investment the region will make in the early 21st century; comparable to building out the freeways in the late 20th century.

According to the Brookings Metro Monitor, Atlanta’s economy is in the unfamiliar bottom half of the largest 100 metro areas in employment growth and recovery. According to Zillow.com, Atlanta housing prices have dropped 29 percent in real terms during the past decade. The only census tracts to gain real value were Virginia-Highland, Grant Park and East Lake, all walkable neighborhoods. Despite this poor performance, Atlanta is still one of the most congested metro areas in the country.

The build-out of the rail transit system will spark direct construction employment. But, more importantly, it will spark billions of dollars in economic development around the stations. It will relieve an over-burdened highway system while reducing energy consumption and pollution. Plus, it will give the market what it wants today, walkable urban places for knowledge-based businesses and their employees.

All it takes is a few more clicks. And the realization that transit really matters.

Christopher B. Leinberger is a scholar at the Brookings Institution and partner at Arcadia Land Co. Jim Durrett is chairman of MARTA and the executive director of the Buckhead Community Improvement District.