‘Triple’ headache: The Explainer

What is the “triple cantilever”?

That’s what engineering wonks call the stretch of the BQE that sits under the fabled Promenade and over Furman Street. It’s called a “triple cantilever” because each level of the 60-year-old structure is extended out over the level beneath it.

Why does it need repair?

The road’s six narrow lanes carry 160,000 cars and truck each day, tens of thousands more than it was designed to accommodate. It’s already overdue for repair, but it must be fixed by 2018 or it could collapse.

What are the challenges?

You know of any other “triple cantilever” nearby? Of course not! This is one unique stretch of road (no wonder it’s on a federal list of “exceptionally significant” highways. State engineers are saying that it’ll take five whole years just to figure out the scope of the project. The state says it will unveil a final plan by 2015.

So what’s the controversy?

The cantilever sits next to the proposed Brooklyn Bridge Park development site, a long-delayed housing and open-space project along the waterfront, and below the Brooklyn Heights historic district. Those 160,000 vehicles can’t be re-routed through the narrow streets of the Heights, so they’ll likely end up on Furman Street or in Brooklyn Bridge Park itself. Brooklyn Bridge Park planners maintain that it won’t happen, but they also said a portion of the park under the Brooklyn Bridge would be open next fall — until the city DOT swiped the land from them for repairs to that bridge. Given that whole portions of the park are already off the table — and nothing permanent has been built yet — it seems likely that Brooklyn Bridge Park will be a highway before — or after — it’s an open space.

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