When the board of the Metropolitan Washington Airports Authority approved an underground Metro station for Dulles International Airport last week, we were guided by two clear priorities: Do what is best for passengers and our communities and do it in the most cost-efficient way possible.

On the first point, the underground station is a far better choice for a facility that will serve Dulles and our region for most of the rest of this century.

It’s better for baggage-laden travelers, who will not have to trek 1,150 feet to an aboveground station to stand in steamy Washington summers or icy winter winds after long international flights. And it’s better as an international gateway to Washington because it preserves the architectural vision of the masterful Eero Saarinen that has made Dulles a design icon worldwide. Washington’s two airports, designed by world-class architects, are worthy of the capital of a great nation. For the airports authority to have decided to provide anything other than a first-rate rail connection at Dulles would have been shortsighted — and soon regretted.

The newly redesigned — and less costly — underground option that the board approved is intended to serve this region for at least 75 years. It’s essential that we get the Metro station right, and now is our only opportunity to do it.

But, mindful of our second major priority, we know that cost is a critical issue, more important than ever in this era of tight budgets. That is why we sent our designers back to the drawing board to give us a less expensive underground option than the one originally proposed and approved by all the regional partners in 2005.

The design they brought back saves about $330 million over the original plan, reducing the added cost of the underground station by about half. We achieved these savings by revising the tunnel length and depth, using a different construction method for excavation, providing air conditioning from an existing airport facility and deciding to put the required electrical substation above ground.

But we are not finished with cost-cutting. We are confident that we can significantly reduce the final costs by finding savings elsewhere in the Dulles Rail project. In addition, the service life of an underground station is more than twice that of an aboveground facility. That will save money for Metro, which will be the system’s operator when construction is completed, and spares future airport users from the more extensive disruptions associated with surface station construction and, later, the inevitable maintenance and repair work.

We are preparing for a future in which Dulles will be an increasingly important economic engine for our region. We expect the number of non-connecting passengers arriving at Dulles to grow from 18 million annually to 42 million. We project that at least 10 percent of those passengers will use Metro to travel to and from the airport, in addition to the thousands of employees who work at Dulles. That will take a lot of cars off Northern Virginia’s clogged roads. When the station is ready in 2017, it will open with at least 5,000 Metro riders per day, or more than 1.8 million a year.

We have already witnessed the consequences of putting a Metro station in the wrong place. The station at Reagan National Airport was originally built at a distance of more than 1,000 feet from the old main terminal, and relatively few passengers made the long hike, especially in poor weather. When we built the new Reagan National terminal, we located it next to the rail station to remedy the problem. Today, about 17 percent of Reagan National’s passengers use Metro, the highest modal share for rail usage of any airport in the country.

We at the airports authority are committed to managing costs well to deliver the highest value in building the best possible system for our passengers and region. The approved design is vastly more passenger-friendly than the alternatives, a key driving factor in airport use and consumer satisfaction. And after we shave additional costs from the project, the final dollar differential will be much lower. Taking all these factors into consideration, a solid majority of the board agreed that the underground station is the best choice for now — and for the next 75 years.

Mame Reiley, Alexandria

The writer is a member of the Metropolitan Washington Airports Authority board and is chair of the board’s Dulles Corridor Committee.

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