I suspect that if you started from the outside, and worked your way in, that even small impacts on traffic outside of the "city center" could have large impacts

I suspect that if you started from the outside, and worked your way in, that even small impacts on traffic outside of the "city center" could have large impacts on the "city center" of New York. And even if it doesn't, having a small positive impact on areas outside the "city center" would still be a good thing.