The Cross Bronx Expressway (CBE) is arguably the most detested road in America. It was cut through thriving neighborhoods, and destroyed a large part of the Bronx -- concentrating minorities in the south of the borough in neighborhoods of grinding poverty.

The powers that be are planning to correct the environmental “injustices” that are the result of this notorious thoroughfare, chiefly the air pollution.

Community advocates, elected officials, and one Columbia Mailman School professor have worked for years to do something about the Cross Bronx Expressway, a major source of air pollution linked to high rates of asthma in nearby communities of color. -- Columbia Health Nov 11, 2021

These green lobbyists have come up with a brilliant idea. Their proposed solution is to cap the expressway by erecting overpasses over the road which will have parks and trees, remedying the problem.

Of course, the initial study alone will cost two million dollars.

New York City Mayor Eric Adams today kicked off a landmark community-driven study to reimagine the Cross-Bronx Expressway, including examining the feasibility of decking sections of the highway. -- NYC.gov Dec 19, 2022

However, has anyone done the math?

Approximately 200,000 vehicles use the CBE each day.

We can create a Cross-Bronx Expressway that both uplifts marginalized communities and provides rapid transit for the 200,000 vehicles it serves each day -- NYC.gov

We can safely assume an average mileage of 15 miles per gallon of fuel for those vehicles, which is probably generous, as a lot of the traffic on the CBE includes belching trucks, and poorly maintained cars, all of which will be stalled in traffic congestion, which can create visible heat eddies in the air (which I have seen in person). Yes, I know some vehicles will be using diesel, but this is a back of the envelope estimate.

These 200,000 vehicles will go across the 6.5-mile length of the road -- (200,000 x 6.5) or 1.3 million miles -- every day: (approx 475,000,000 miles per year). Divide that by 15 miles per gallon and we have 86, 667 gallons of fuel being used per day, as a very rough estimate.  Approx. 31.6 million gallons per year.

A gallon of gas produces approx. 20 pounds of carbon dioxide.  Our estimate will ignore, for now, the carbon monoxide output. So 86,667 gallons of gas will produce approx. 1.73 million pounds of C0₂ per day.  In one year, that would translate to roughly 631 million pounds of carbon dioxide.

However…

A tree absorbs approximately 25kg [55 lbs] of CO2 per year. -- Ecotree.green

At that rate, over 11 million trees would have to be planted along the CBE.  And mind you, other sources say trees absorb even less carbon dioxide… around 48 pounds.

How about this?

One acre of trees annually consumes the amount of carbon dioxide equivalent to that produced by driving an average car for 26,000 miles. -- Thoughtco

So, let us divide our 475 million vehicle-miles (per year) by 26,000 vehicle-miles (Note it was one car/vehicle annually) per acre. And we have approx. 18,270 acres of trees which would have to be planted, along the CBE which is only 6.5 miles in length.  18,270 acres is approx. 29 square miles of dense forest.  Or roughly 2.2 miles of forest on both sides of the roadway.

It ain’t happening.

And we have not even considered carbon monoxide, or the soot which comes out of those trucks, etc. There is no way that capping/decking the CBE can correct production of carbon dioxide and other air pollution.

Now, there might be an esthetic aspect to creating some parks over the roadway. It would certainly look nicer, but as this is the Bronx, how nice can it really get?

Yet, the airspace/roadway under those parks will concentrate carbon dioxide from the exhaust, which is heavier than air. However, if the overhead parks are kept small in length, there should not be too much of a problem unless one is stuck under the overhead cap in crawling traffic during a windless summer day, with every car’s air conditioning running and the heat eddies fuming up from the pavement, which is pretty par for the course on the CBE before a Yankee ball game.

The overhead parks cannot be too long, as there will have to be punctuated spaces open to the sky, or the drivers will all suffocate. Those living next to the park might have a pleasant sight, but those living next to the still open spaces will get a double dose of pollution. But in the Bronx, who will notice?

The noise coming out of those effectual punctuated mini-tunnels will echo back to Manhattan, and out to Long Island. Sound absorption technologies will have to be implemented.  And the upcoming air drafts from those even more concentrated heat eddies will be considerable. Anyone in the overhead park who dares fly a kite will be in danger of being carried away.

What such caps will not do is address the air pollution. For that you need the air coming in from Pelham Bay and the forests of upstate New York. It is the outside forests which clean the air.

Yet, this stupidity is what is being sold to the public as a remedy for pollution. It is more green idiocy.

I do not mind if one or two parks are planned, but they will not help the environment in the area. They would pretty up the Bronx, but add all but nothing to the air quality

So, now that I have solved the problem, will Mayor Eric Adams pay me the two million dollars set aside for the feasibility study?  I think I have earned it.

Image: PxHere