Instead of asking "how do we power 1.6 billion vehicles" we should be asking "how do we eliminate the need for 1.6 billion vehicles". If we can eliminate the need for so many powered vehicles we can eliminate the resource extraction and pollution caused by powering them. We eliminate the resource extraction required to build them. We eliminate the costs of disposing of them at the end of their lives. We eliminate the extraction of resources and the destruction of Nature required to build vehicle infrastructure, and the costs of maintaining and eventually decommissioning that. We might well strengthen local economies and local communities by shortening supply chains and distribution networks. And, there are likely social benefits to not locking people in metal cans for hours each day.
* If you find yourself on a sinking ship, you might save yourself by clinging to the top of a piano to stay afloat. This does not mean that a piano top is the best design for a life preseerver.