Something I noticed recently was the amount of steps you have to take to secure yourself in a well-lit restroom.  The other day, while at UHS, I had to lock the door with an additional deadbolt besides the lever handle lock to signal on the outside that the bathroom was occupied as well as turn on the light.  Lock, lock, light.  Three steps.  Airplanes do it in one.  To turn on the lights of a plane restroom, you must slide the lock, which acts as the switch.  Why don’t we do this more widely in bathroom use cases?  Like at doctor’s offices, restaurants, etc.  Single use, all gender bathrooms are spreading for the better, and have been backed up by architectural studies to show they are more space-efficient and cost-effective in addition to being humanitarian. This will not only ensure privacy but save electricity for businesses and institution.

Article on All Gender Bathroom Architecture: