If Doctor Who was set in modern day America, what would the Tardis be?

Coke Machine

No, sorry, my fault for not being specific - His Dark Materials is a book by Phillip Pullman, unconnected to Dr Who. I mentioned it because in that book your idea did seem to work. It wouldn’t really be mobile enough though. The Tardis should be something you can imagine moving, even if being pulled by something else, rather than having to be packed up into discrete pieces and carried around.

A car or a camper or a panel van are all too large. Part of the beauty of the police box is that it occupies such a small footprint; it can fit inside rooms without a problem.

The Porta-Potty fits the small footprint requirement, has a person-sized door, and people all over the world are accustomed to seeing them in all kinds of settings: sidewalks, fields, road construction sites, etc. There is nowhere that one could be found that people wouldn’t just walk past it and at most wonder if the project that occassioned it’s presence was over already and the rental company (Gallifrey Maintenance & Waste Disposal Services) just hadn’t picked it up yet or if the project hadn’t begun yet. The only problem I can see with it is that they lack a keyed lock, but I’m sure that the presence or lack of a need for one could be explained some how.

I know exactly what you’re talking about- really good one. Even comes with the locking hinged door, no windows, and unlike the portapotty something few if any people would even try to open anyway. My choice so far.

Ha!!

PS- They’re called transformer boxes.

I think it would have to be something like the portable toilet or the Fotomat. It would have to be someplace that generally one person would walk into. Not something that could seat several people, like a van. Part of the charm is everyone going, “how’re we all going to fit in there”. Also I don’t think a vehicle would be in the spirit of the TARDIS since all too often people think they have the Doctor surrounded in his box and they know there is no way for him to escape, but then he does. You couldn’t pull off that bit if he and his friends all got into a van or cab or something.

The police box idea was brilliant, wasn’t it?

Going to have to go with the storage shed idea or the porta-potty.

But I’ll post this for USA relevance since it involves Superman.

Except the Tardis makes people kind of…not notice it. It fits in wherever and whenever it goes.

Depending on the area, they can have locks. Admittedly, that usually means chains as well, but I’ve seen locks.

Or bottle recycling machine.

Oh, thank you. I hate not knowing the names of things. And that’s exactly the thing I was thinking of.

I suppose the Tardis could be a Dumpster, too, but that would be rather undignified.

Or a silver Delorean?

It would aptly be more than meets the eye.

Since size is irrelevant, I’d go with an old-time saloon, complete with the curved wooden door. What’s more uniquely American than cowboys?

If size doesn’t matter, it would be a Starbucks.

I was thinking Starbucks, too. In Canada, Tim Horton’s. Another option … one of those water system access tunnels that is raised above ground.

A corner mailbox

Which confuses everybody by being a lot smaller on the inside.