I have heard all the excitement about converting the Tappan Zee Bridge into a 3 mile green park once it is replaced by a new structure, and I have to admit it sounds pretty cool, but I wonder if it would work in practical application. There are two big concerns. The first is the physical efficacy of the bridge being a park that would be a cost saver over demolition. The second is whether a park on a narrow span over the widest part of the Hudson would even be usable most of the year.
Saving $150 million by not demolishing the structure does not occur in a vacuum. The new greenway would still need to be maintained and converted over to sustain several feet of soil to have grass and trees, would require irrigation and other services, and would still be an expense to manage. It would require police. It would need bathrooms. There would have to be some means of having vehicles navigate it for EMS or emergency. If there were any food or retail on the span they would need infrastructure as well.
While I am no engineer, I have to wonder if the elimination of traffic would be sufficient to counter balance the stress of tons and tons of earth and soil needed to make the greenway work. Just holding up its own weight after 56 years must be a concern. How would it be-and what would it cost-in another 10 years? or 25 years? That would be less expensive than maintaining the current bridge, but it would have to be added to the cost of maintaining the new bridge as well.
But even if the structural and logistical concerns could be addressed, I have to wonder what the quality of the greenway experience would be most of the year out in the middle of the Hudson. We are talking about a bridge that has wind advisories and a speed limit of only 40 MPH for good reason. It isn't windy out there sometimes. It is very windy most of the time. I cannot imagine it being a pleasant or warm setting anytime between October to May. That is a big chunk of the year where you won't see many frisbee games or baby strollers.
Moreover, the new bridge will be built right next to the old one, so that theoretical oasis of pastoral beauty over the water would in actuality be right next to an 8 lane Interstate with no natural buffer.
Rather than have future generations pay for a park that could end up being less useful than we might think, why not put the old bridge to work for us? To me, it is a natural wind farm. Let's put some windmills out on that thing when it closes and get a few decades of energy from it instead of splitting some atoms. It couldn't be any noisier than the Interstate right next to it, could it?