My city doesn't even have bus fare. It's not like they're grabbing my biometrics when I step in. They're not trying to identify me when I walk on.

You just walk on, wait, then walk off.

It may not be the most private way of transport but it's not actively collecting data on you, which is what this is about.

EDIT: Further, it's just easier for a car to collect data on it's owner. When you buy a car, you get a Title which registers the Vehicle Identification Number to the owners name. Then, when you're driving, because you're in public you're required to have your Drivers License, Registration, Insurance, a License Plate and up-to-date Tabs all very specific identifiers that identify both the driver and the car. The cars sensors only have to identify the owner, to whom it is already registered, and so they know the data they're collecting is from one person/one family.

I've seen my cities bus budget. They have cameras on the bus for the protection of drivers but can barely afford them. They're definitely not dumping money into shit like facial recognition. I don't even need an ID to ride the bus. I can walk on with empty pockets and no one is gonna tell me I can't ride the bus without ID. If you drive without your license, you can get it taken away.