So the clearance is needed for the footrests found on wheelchairs, and if you make the stall big enough, you don't have to provide the floor gaps. It's interesting that the ADA regulations have become an important factor in design starting in the 1990s, yet I remember that public restrooms have had those floor gaps since much earlier than that. I wonder if the logic went like this: floor gaps have existed since at least the 1960s --> people with wheelchairs found the gaps useful to maneuver in the restroom --> the ADA codified this into a regulation in the 1990s.

To save everyone from having to wade through stack exchange, here is the ultimate link[1]:

"604.8.1.4 Toe Clearance

The front partition and at least one side partition shall provide a toe clearance of 9 inches (230 mm) minimum above the finish floor and 6 inches (150 mm) deep minimum beyond the compartment-side face of the partition, exclusive of partition support members.

EXCEPTION: Toe clearance at the front partition is not required in a compartment greater than 62 inches (1575 mm) deep with a wall-hung water closet or 65 inches (1650 mm) deep with a floor-mounted water closet."

[1] https://up.codes/viewer/ada/chapter/6/plumbing-elements-and-...

The gaps underneath also make it way easier to mop the floor, and minimize corners and crevices for gunk to collect in.

Source: was a janitor for a while in my youth.

Minimum gap size for the gap at the top and bottom, right? A minimum gap size for between the different wall pieces and the door would be crazy.

Ok, so cost and cleanability might be incentive so have doors like that, but not incentives to make regulations.

Those regulations likely there for "decency and safety". E.g. to discourage people having sex, or to make it more obvious if someone passes out. That is: the regulations really are there to make reduce privacy.

There might be good arguments for reducing privacy, but that is still the proximate goal of the rules.

I think the end goal is making it harder to do heroin in a bathroom.

Haha, probably cocaine as well. Some public restrooms seem designed to minimize flat surfaces, private access to clean water, and secluded locations, while others (like in some night clubs) have randomly placed shelves with hard, easily wipeable surfaces, etc.

Not entirely random: you need a place to set your drink while using the restroom.

In a public restroom, if there's a place to set a drink, trash cups will accumulate there. Then someone will have to be paid to clean them up.

Indeed, this one of the many reasons some night clubs have bathroom attendants.

I can understand this in a public restroom, but why do the bathrooms in my 30-story office building have to be this way?

I've heard that they were more to discourage illicit drug use than "indecency".

Who in their right mind would have sex in a public restroom? That's just disgusting. I very much doubt it has anything with reducing privacy.

We learn something every day

Whether we want to or not.