Built up in the 1970s and ‘80s, Westchester County’s “Platinum Mile” is a cluster of corporate office parks along the I-287 corridor that once brought good jobs and tax dollars to the county. In recent years, however, big-name companies have been packing up their offices and heading back to the Big Apple. Others, like Starwood Hotels, are off to Stamford, CT. For those left behind, the question is: Why? And can something be done to stop the bleeding?

Across the country, the suburban “Corporate Campus”—typified by modern buildings, manicured lawns and lots of parking lots—was a product of a certain era of corporate culture that strove to consolidate operations, build teamwork and improve efficiency. Suburban job sprawl changed landscapes and economies across the nation, fueled by local tax incentives, lower real estate prices, transportation and land-use policies, as well as demographic shifts, such as “white flight.” Today, the corporate campus is being labeled a dated model and “bright flight” is the new term being floated to capture a demographic shift of bodies and brains back to the center.

“It’s a switch back to ‘I don’t want to be isolated in an office park, I want the vibrancy of a downtown, public transportation and the ability to shop and walk around,’ ” Gerard Hallock of Colliers International told the Wall Street Journal earlier this month. As personal computers and mobile phones transform the relationship between employees and their desks, corporations are now leaning towards a model where employees are out in the field, and urban corporate offices offer easy, centralized access for both clients and workers.

Unfortunately for Westchester, bodies and businesses can move and adapt faster than buildings and communities. The county now has 6 million square feet of vacant office space—a 17.9% vacancy rate compared to New York City’s 10.7% rate—and jobs are down a whopping 25%, from 2005 to 2008.

If, as some believe, this is a structural shift in business culture that won’t be turned around with the economy, major interventions will be needed. One business group has concluded that the answer is one of marketing—adding amenities like health clubs and day cares, and advertising the community’s strengths, like lower rents. Westchester County Association president William Mooney recently said, “Frankly, we’re a better deal than New York City.”  But the old model of cheap rents and tax incentives doesn’t seem to have worked.

A more successful strategy could be to bring transit to the I-287 corridor, such as the bus rapid transit system envisioned in the state’s long-running study of replacing the Tappan Zee Bridge. A Brookings Institution study reconfirms that one way to compensate for recent demographic shifts is to improve the links between city and suburban transit. However, Westchester County Executive Rob Astorino recently suggested that the Tappan Zee be replaced without the addition of new transit on opening day.

Mooney has also suggested that the county’s economic development efforts shift primarily to its cities, such as White Plains, Yonkers, New Rochelle and Mount Vernon. This would fit with the state’s commitment to concentrate infrastructure dollars on downtowns, as embodied by last year’s Public Infrastructure Policy Act.

Other areas of the country are facing the issue of aging corporate campuses, and many are coming to the same conclusions. “Your transportation investments ought to be driven by your desire to grow the economy, not to spread investment across the state as if it were peanut butter,” Frank Beal of economic development group Metropolis Strategies told Chicago Business.  “The global economy is changing in ways that demand higher densities that can only be serviced with transit.”