I confess, on that part I was just taking funny car names from the list I posted of old defunct manufacturers. Dort instantly became one of my favorite car names.
The OP said automobiles. We can not rule out either commercial vehicles, or motorcycles. In fact, we have to count them.
Now what about electric powered bicycles? Do we count them? I see them on the shoulder of highways around here. They are automobiles by definition.
I think that we need a definition of terms here. Automobile, today, highway?
Someone ruled out Studebaker, Two of my neighbors use their Hawks as daily drivers. Last I knew, we lived in the USA. BTW, They do their own maintenance, so no local repair shop is going to count those cars.
While the number the OP asked about is indeed finite, I do not believe that we can figure out that number. I am not sure that we can come up with a WAG, say nothing about as SWAG.
Why do we have to count them? Automobile is synonymous with “car,” not “road vehicle.”
Let’s limit this to gas or diesel vehicles.
Here there is ‘Subaru’ and ‘Not a Subaru’.
I think you misread that. I didn’t rule out Studebakers. I ruled out all antiques like the Studebaker for a somewhat related project I once worked on.
Obviously this is a long-tail problem. Which means strictly speaking it’s unanswerable. We’ll always have some error bars based on what constitutes “driving”, “road”, and over what time interval? Plus of course what constitutes a “make” and a “model”.
To a very crude first approximation there are two makes/models: Toyota Camry & Freightliner Class I tractor. Each time we add another lower-volume make/model or subdivide an existing make/model, we get closer to the elusive ineffable truth. But we’ll never get there until/unless we have total omniscient knowledge of everything going on within our shores.
I have an idea: let’s ask NSA. They’re sure to know!
Why limit to gas or diesel? I see dozens of all-elecric vehicles every day. I also see LNG and even propane powered vehicles, though these are modified production cars so maybe they don’t count.