A proposal to build a Cross Downtown Brooklyn tunnel, an idea studied by the state in 2010, is sparking new interest. It would redirect traffic from the ailing BQE, cut travel time and improve quality of life, according to Cobble Hill resident Roy Sloane, who came up with the design in 2010. This map shows the alignment of the proposed tunnel. Map courtesy of Roy Sloane

A proposal to build a Cross Downtown Brooklyn Tunnel, an idea studied by the state in 2010, is sparking new interest.

As the Brooklyn-Queens Expressway from Atlantic Avenue to Sands Street faces a massive, $3.4 billion reconstruction, a once-in-a-lifetime window of opportunity has opened, says longtime Cobble Hill community leader and graphic designer Roy Sloane. Sloane came up with the tunnel concept at a planning session in June 2010.

Sloane, former president of the Cobble Hill Association, is the first to admit he is not an engineer. He was, however, a member of the original Brooklyn-Queens Expressway Advisory Committee and the longest-serving citizen member of the Community Board 6 transportation committee.

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A roughly 3-mile-long tunnel, running from the Gowanus Expressway vicinity near the intersection of Fourth Avenue and the Prospect Expressway in the south to Flushing Avenue at the north end, would cut travel time from Gowanus to the Brooklyn Navy Yard by 10 to 30 minutes per trip, Sloane says. It would handle truck traffic bypassing local streets, and much of the cost of constructing and maintaining the tunnel would be borne by roadway users. The tunnel would be tolled, and construction could be financed with bonds.

Would eliminate need for Promenade highway

A Cross Downtown Brooklyn Tunnel could eliminate the need to build a temporary six-lane highway atop the Brooklyn Heights Promenade while the triple-cantilever beneath is rebuilt, supporters say. The “innovative” temporary roadway plan proposed by the city’s Department of Transportation, has shocked local residents and businesses, as it would bring the noise and pollution of 153,000 cars and trucks up to the level of neighborhood yards and streets for years.

With a tunnel bypass, the existing BQE section, which includes the triple cantilever in the Heights, would remain in place as a local feeder road.

“If we could remove the weight from the triple cantilever and cut it to two lanes plus a recovery and merge lanes [in each direction], we would take a third of the weight off the structure,” Sloane told the Brooklyn Eagle.

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With less weight, a rebalancing toward the cantilever wall and a lower speed limit, “I think there is a very good possibility that the Triple Cantilevered Roadway could be rehabbed in place instead of a complete rebuild, substantially reducing the cost and impact of the project,” he said.

Sloane is in favor of reducing the speed limit on the triple cantilever section from 45 miles per hour to 25-35 miles per hour to reduce vibration. He is also recommending de-certifying the BQE from Hamilton Avenue to Sands Street as a Federal Interstate Highway.

State DOT studied tunnel ideas in 2010

A 2010 NYS DOT study looked at six possible tunnel routes, including the one suggested by Sloane, labeled W-2. According to the state report, the W-2 tunnel would pass all major engineering, operational and structural considerations. Another advantage: the six lanes of the BQE would be maintained during the construction period.

The state also found several disadvantages. The plan would involve “considerable property acquisition to construct portals and one or more ventilation structures,” NYS DOT said.

In addition, tunnel portals would be located in the vicinity of North Portland Avenue, areas that include minority or low-income populations. These include the Walt Whitman and Ingersoll housing projects. Part of the criteria in the evaluation process was the desirability of avoiding negative effects to minority and low-income populations.

Sloan told the Eagle that the portal would not be near the housing projects.

NYC DOT revisited tunnel ideas in 2016

City DOT told the Eagle that the agency explored the various tunnel options in 2016 and came to the conclusion that there were a number of factors making the idea infeasible.

According to the city, some of the tunnel routes originally proposed were impossible due to infrastructure issues, including existing subways and water tunnels. Some of the tunnels deemed feasible could crack foundations of historic buildings and brownstones, the source said, and tunnel entrance, egress and ventilation would require property seizure.

The BQE is currently six lanes, and a tunnel would only have a maximum of two lanes in each direction, DOT said. In addition, a tunnel would not replace the connection to the major East River crossings.

Sloan said NYC DOT’s own report contradicts a number of these assertions. DOT’s study looks at both four-lane and six-lane tunnel configurations, for example.

Sloane says his tunnel plan “survived the City’s 2016 feasibility study.” And, earlier, just before the state dropped the project, NYS DOT’s consultant approved the geology and alignment and said that the tunnel would be deep enough to pass underneath the infrastructure at Atlantic Yards and the Long Island Rail Road to leave room for a tunnel.

City DOT estimated the cost for a tunnel would range from $7 billion to $8 billion. Sloane said that much, if not all, of this cost would be financed for through tolls paid for by roadway users.

Time to ‘take a new look’

“There’s no way DOT’s ideas to repair or replace the cantilever make any sense,” said William Harris, a member of the Community Board 2 Transportation Committee in 2010, when the committee was working with the state DOT on a BQE solution.

“The issue has become so pressurized that people can’t understand it holistically. We need to stand back and take a new look,” he told the Eagle.

“In one of the last meetings in 2010 — before the state left in the middle of the night — we had a charrette with 40 or 50 people, six to seven tables. A vote was taken on the best approach regardless of cost. Eight out of nine came up with the tunnel as the best solution,” Harris said.

Harris feels the city DOT is shying away from a tunnel because of “ignorance, lack of initiative, fear of what’s going to happen and playing on the safe side.

“All of the easy solutions have been presented. Now we have to think boldly like we used to think — and big, like building bridges over the East River,” he said.

Patrick Killackey, a member of CB2’s Transportation Committee, said that the city’s own analysis “concluded a tunnel option is feasible in terms of geometrics, geotechnical issues, constructability, and operational requirements and Federal Highway standards.”

“The critical issue for the near term is that city include this option in their environmental scoping process so as not to foreclose it,” he said.

Borough-wide benefits

Unlike other BQE bypass ideas examined by the state, the Cross Downtown Brooklyn Tunnel option would benefit the entire borough, Sloane said.

The W-2 tunnel would cut a 25-45 minute drive to 3-4 minutes, and has a “throughput advantage,” he said. “With four BQE lanes and four to six in the tunnel, that equals a minimum of eight moving lanes through the BQE corridor instead of the current six lanes available to through traffic.”

That means less through traffic in Downtown Brooklyn, the possibility of carbon recapture from the tunnel and improved residential quality along with pedestrian and bicycle safety, Sloane said. Residents living near the BQE in DUMBO, Vinegar Hill, Brooklyn Heights, Cobble Hill and Carroll Gardens would receive an immediate quality-of-life improvement from the reduction of number of moving lanes from three to two and from less noise and vibration by reducing the speed limit.

Currently, a large amount of traffic uses the BQE for intra-Brooklyn travel, Sloane said. With a tunnel, “It won’t have to go through Park Slope.”

The plan also has the benefit of preserving Lower Van Voorhees Park, Sloane said. And with only local traffic on the BQE triple cantilever, the tunnel might also lessen the necessity for the sound attenuating berms in Brooklyn Bridge Park. “With a quieter park, you wouldn’t need the berms and you could have a bigger park — and, most importantly, preserve the Promenade as it exists today,” he said.

Other proposals

Inspections have found that the section of BQE from Sands Street to Atlantic Avenue is so rickety it needs to be replaced before 2026, or tens of thousands of trucks daily will be rerouted through Brooklyn’s residential streets.

As an alternative to DOT’s Promenade Highway proposal, the Brooklyn Heights Association has proposed a “Parallel Highway,” designed by Heights-based Marc Wouters Studios. It would move traffic to a temporary two-level structure west of the existing triple cantilever underpinning the Promenade, rather than atop the popular walkway.

NYC DOT says the BHA plan is one of several alternatives under consideration, including a more traditional option which would replace the BQE lane-by-lane. This option carries its own drawbacks and would take longer, DOT says.

Peter Bray, BHA’s executive director, told the Eagle that the organization welcomed the reintroduction of Sloane’s tunnel option. “The BHA welcomes creative ideas from the community that can contribute to broadening the alternatives DOT will consider as part of its upcoming environmental assessment of the BQE reconstruction project,” Bray said on Thursday.

He added, “It has been our long-standing demand that DOT remove the Promenade Highway from consideration, listen to the community, and come up with a better, less environmentally destructive plan.”

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The full Cross Downtown Brooklyn Tunnel proposal can be found here.