The Public Health Case for Decking Over the Cross-Bronx Expressway

Capping the sunken parts of the highway with parks would be more than worth the cost once you factor in the health benefits of increased physical activity, according to researchers at Columbia University.

Covering the below-grade sections of the Cross-Bronx Expressway with parkland would produce significant public health dividends, according to a new paper from researchers at Columbia University. Photo: Google Maps
Covering the below-grade sections of the Cross-Bronx Expressway with parkland would produce significant public health dividends, according to a new paper from researchers at Columbia University. Photo: Google Maps

Capping the sunken sections of the Cross-Bronx Expressway with new parkland would save lives and money, according to a paper from researchers at Columbia University published in the American Journal of Public Health.

The Cross-Bronx is an east-west gash across the borough, dividing neighborhoods and saturating streets with traffic and pollution.

Researchers evaluated the cost-effectiveness of capping the 2.4 miles of below-grade sections of the highway with public space. They found that building a park over the sunken Cross-Bronx Expressway segments would increase access to public space and physical activity, decrease noise pollution, and improve cardiovascular and mental health. In their model, those benefits would outweigh the expense of building the deck parks.

Capping a highway costs less when it’s already below surface grade. Using construction cost figures from similar projects, the Columbia researchers estimated that building deck parks over 2.4 miles of the Cross-Bronx would cost about $750 million.

The benefits, meanwhile, would accrue financially, mainly in the form of higher property values, and to public health, mainly via increased physical activity and cardiovascular fitness thanks to improved park access. New housing construction and subsidies could maintain affordability for residents to offset rising property values, the researchers said.

“You would be solving a lot of problems with one investment,” author Peter Muennig told Streetsblog. “It’s not just saving lives, it’s also saving money.”

Investments that save both money and lives are rare in public health, the researchers note, and are usually limited to preventive measures like vaccines.

In light of the cost-effectiveness of decking the sunken parts of the Cross-Bronx, Muennig said it’s possible that net benefits could be derived from other deck park projects, including ones that require some form of excavating, like Boston’s Big Dig.

“You can put a lot more into an infrastructure investment than you might otherwise anticipate because these health returns are large enough to offset the cost of the investment,” he said. “It’s definitely worth looking at other projects to see where you find some value.”


    Although I’d rather see this asthmaway deleted entirely, decking it would be EXTREMELY beneficial!

  • MFS

    It sounds really nice, but when they did the “Fix the Ditch” study along the BQE near Columbia Street, turns out you need some really big ventilation towers to cap a highway and put parkland on top. :

  • Vooch

    The best solution would be remove the blight and restore the pre-existing street grid.

    Selling off the land would generate billions for the city ( finally fund those pensions eh ) and instead of the value subtracting blight of the highway – we’d have a restored street grid with a half a trillion in property paying property taxes !!!!

    remove the blight

    restore the pre-existing street grid

  • Rex Rocket

    New construction in New York City seems to be based entirely on tax abatement, so for the first 75 years the only tax revenue you’re going to see is sales tax from the Starbucks, CVS, nail salons, etc. (It’s the Bronx, so at least there won’t be any non-productive bank branches hogging retail space).

  • Vooch

    Funny – but sadly true. I reckon thevprooerty tax gimmes could be reduced to 15 years. :)?

  • Joe R.

    For now. Might not be the case in 5 to 10 years if we push electric vehicles. This is yet another reason government should encourage zero emission vehicles. It becomes much less expensive to cap highways.

  • HamTech87

    Interesting. Would be able to create a fabulous cycle track across the BX all the way to the GW Bridge. Gives even more impetus to improve cycling routes on the GW Bridge.

    The Cross Bronx Expressway is capped at Parkchester station on the #6 train. What’s that feel like for pedestrians and cyclists above ground? What’s the air quality like?

  • HamTech87

    Just did a Google Street View. It’s not great. More of a giant 4 1/2 lane road for cars with very wide crossings.

  • HamTech87

    Awful place to cross a street. Notice those people standing in the car lane trying to get a jump on the crossing. Let’s hope any capping plan doesn’t leave us with this situation.

  • AnoNYC

    Parkchester is very walkable but the oval is pretty busy with all kinds of street users. The city recently came calmed traffic there so it’s better than it was.

    Good use of the space over the highway.

  • Rex Rocket

    Moses would deck it–with another expressway.

  • urbanresidue

    Crotona Parkway bridging over the Cross Bronx is a better example.

  • HamTech87

    Yes. Looks like NYC-DOT could do a lot more with Crotona Parkway. Protected Bike Lanes or doing more with the central promenade.

  • HamTech87

    Thanks. Must have been really recent since Google Maps streetview shows the photo as September 2017.

  • bolwerk

    Hell, why stop at parks? If you want to make money, fill a public health need, make the area more attractive to pedestrians (I know the city hates cyclists), and even improve the housing stock, why not put some small-scale attached mixed use housing over sunken sections?

  • redbike

    I’d be cautious about advocating for housing over the roadway. There’s historic research showing increased CO both outside and inside the apartments above the Trans-Manhattan Expressway. “Historic research”: a very quick / superficial search turned up nothing more recent than the 1970’s. Different fuel formulation and emissions controls affect other car and truck exhaust components, but I expect CO has remained constant. When (not if) zero-emissions vehicles are a significant percentage of what’s on this road, residential development above it might make sense. I’m unsure if there’s an engineering or architectural solution short of zero-emissions vehicles to sufficiently mitigate this risk to health so that living above the roadway would incur no additional health risk as compared to surrounding neighborhoods. (And closing the Trans-Manhattan / Cross Bronx Expressways – particularly to trucks – is a pipe dream.)

  • AnoNYC

    Sept 2017 should be up to date. The DOT extended the west curb on the north intersection of Virginia Ave which is a major pedestrian crossing point and pedestrianized the southern part (forced turn from northbound Virginia Ave into the circle now.

    The number of lanes could be reduced further though, especially in the southern half of the circle. I would knock it down to two moving lanes on that side. Three moving lanes on the north half, with one dedicated to turns into Metropolitan Ave.

  • AnoNYC

    At the minimum the city could extend the curb on the north side of the street through the parking lane to reduce the crossing distance. Personally, I feel that half could get away with two moving lanes westbound, and one turning lane into Metropolitan Ave/Virginia Ave.

  • AnoNYC

    Yup. Could use further calming.

  • AnoNYC

    I would like to see it decked. If automotive traffic volumes one day decline maybe we could get BRT along the inner or outer lanes.

  • AnoNYC

    I think by the time decking would be become a reality we would see a big increase in the number of EVs on the road.

  • bolwerk

    Yeah, I’d thought through that and almost didn’t post because I wasn’t sure how to answer that. But in the end I figured, well, there’s housing next to the roadway anyway and that’s probably even more exposed. Likewise, decking over, with housing and parks alike, creates a problem of concentrating pollution as it exits from the ends of the the decked over sections.

    I guess you could argue that a park is a place people might go for a few hours at most, while living 24/7 over polluted tunnel sections is different, and it’d be best not to encourage more people to live near those roadways – and parks are simply accommodating the people already there.

  • cjstephens

    I’m all in favor of decking this over, but the public health case is probably the weakest case to be made. If you want this to happen (and I’ll repeat, I think it’s a great idea), don’t even mention the health benefits. Start by getting developers interested: acres of vacant land not far from Manhattan! Figure out a way to finance the decking by selling off the new land to developers (hello, Hudson Yards). Then require the new development to have plentiful affordable housing (not as tough a sell in the Bronx as it is in Manhattan or much of Brooklyn) and a linear park (shades of Westway). Then when the usual anti-development, NIMBY and BANANA crowd gets riled up, as they always will, shut them down with: “and by the way, this will solve the asthma epidemic in the neighborhood. Oh, what, you’re _in favor_ of kids having asthma attacks?”

    Boom: the air quality gets better, there’s more affordable housing, parkland gets built, and Vooch gets his pre-existing street grid back. Plus, I dunno, something about bikes. Everybody wins, right?

    But if you lead with “public health”, nothing will get done. I’m not saying that’s how the world should work, but decades of public advocacy haven’t been very effective.


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