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Md.’s new transportation chief explains ‘practical design’ approach to Purple Line

Pete Rahn, the newly appointed Maryland transportation secretary under Gov. Larry Hogan (R) is seen at the BWI MARC station on Thursday, Feb. 12, 2015 in Linthicum, Md. (Amanda Voisard/For the Washington Post)

Want to know more about what Maryland’s acting transportation secretary is thinking as he considers whether the state should build a $2.45 billion light-rail Purple Line?

In his first sit-down interview Feb. 12, Pete K. Rahn told The Washington Post that he and his staff are reviewing whether a 16-mile transit line between Montgomery and Prince George’s counties could be built for less money. (During the gubernatorial campaign, Rahn’s new boss, Maryland Gov. Larry Hogan (R), called a Purple Line and a $2.9 billion Red Line planned for Baltimore too expensive.)

In a Feb. 15 story, Rahn said he and MDOT staff are reviewing the costs at different “decision points” along the Purple Line’s decade-long planning process, including designs for the 21 stations and the choice of a light-rail train line over a less expensive rapid bus system.

Here are more of Rahn’s Purple Line insights that didn’t fit into our profile of the new transportation chief:

“I’m sure everyone is aware we’re looking at its costs,” said Rahn, a former transportation chief in New Mexico and Missouri. That includes, he said “what the need was for every feature in the project.”

Rahn, whose nomination is pending Senate confirmation, said he’s focused on “practical design,” an approach he used in both New Mexico and Missouri. He defined “practical design” this way: “You prioritize the needs of the system over the wants of a project … When we deliver a project that meets the needs for less money, there are more resources for other needs in the system.”

That includes, he said, examining “the value of all those extras” and “how much in a project is wants and how much is need?”

Engineers who design transportation projects, he said, often are trained “to address every conceivable thing that could go wrong” rather than use a more practical, cost-efficient approach. For example, he said, the Missouri highway department once used a 17-inch across-the-board standard for the thickness of new pavement, whether a road was being built atop hard rock or soft clay.

“Practical design says if we know we’re building on rock, we don’t need 17 inches of pavement,” he said.

On a light-rail line, Rahn said, long-term operating costs could be reduced by running trains less frequently.

He said no decisions have been made about possible cost-cutting measures but that he doesn’t foresee changing the proposed route or building only part of the 16-mile alignment planned between Bethesda and New Carrollton. He noted that rapid-bus systems are cheaper to build but more expensive to operate long-term.

Ultimately, Rahn said, Hogan will decide whether building a Purple Line — in whatever form, at whatever cost — is worth it.

“I’m viewing this from the standpoint of ‘Let’s see the best number we can come up with from a practical design approach,’ ” Rahn said. “I plan to give [Hogan] options.”

Bid proposals for a 35-year public-private partnership in which a team of private companies would design, build and operate a Purple Line, in addition to helping finance its construction, are due March 12. Rahn said the state might extend that deadline if bidders think they could do more to reduce costs, he said.

Rahn said he hopes to make a recommendation to the governor ​before the General Assembly adjourns in April.