Noah Kazis from Streetsblog runs the numbers:
"In total, the inventory shows New York City reducing its carbon emissions from 56.6 million metric tons of carbon dioxide equivalent to 49.3 million. Only a small fraction of that reduction came from transportation, however: 359,000 metric tons. The bulk of that change came from improvements in the transit system: huge reductions were posted in emissions from diesel buses and in the amount of electricity used by the subways and commuter rail."
Thanks to Noah Kazis