What this fails to consider is that auto-driving cars are reused throughout the day. They might take the main bread-winner to work, then return home (on their own) to take the spouse food shopping and kids to soccer, then take an unrelated person on their chores, then back to pick up the bread-winner from work, and finally off to the cleaning location where the car is sanitized, refueled (electric or gas or hydrogen — don’t matter), and maintained. There’s very little inner-city parking needed since the car is almost always in motion. Passengers will end up waiting for the next available car, but that’s easily fixed if neighbors share cars (a “pool of cars”) or share rides (a “car pool”). A self-driving car can take the dog to the vet, pick-up groceries or dry-cleaning, or return drunk people safely home. Since electric cars are so cheap to run, I expect people will not think twice about sending cars on more errands, and have physical ports built into their residences (like mail boxes but standardized and for larger boxes) where the car can safely deposit deliveries without human interaction.

Note that splitting a large market (that everyone has to drive to) with multiple smaller markets only reduces the mileage of the shoppers. The delivery trucks would travel far more miles, and with more stops, over smaller roads, and these diesel 18-wheeler trucks are more far polluting than electric cars. Those who suggest walking/biking to the market may never have bought frozen food or had to tug a case of beer or 2 gallons of milk home, and don’t have a solution for the disabled, elderly, or single mom with 3 young kids scenarios.