This is perfect – Don Shoup talks about the relatively insane ways planners select the number of parking spaces needed for a particular business – 1 for every 2.3 nuns in a nunnery, 1 per every 25000 gallons in a swimming pool, etc – Well this article compares the similarities and differences between the need for parking spaces and the need for toilets in a particular facility. Not only is it hilarious, but it hits pretty close to home. A sample:
As mentioned above, one rationale for requiring them (toilets) with buildings is so people won’t have to use the streets (or not too much anyway).
Another reason they are required with buildings is so people don’t freeload on the facilities of neighboring buildings. In parking this is called “spillover”. This might be apt for toilets too, come to think of it.
There are eight comparisons listed, and many more in the comments – thanks to Paul Barter from Singapore and his blog for this gem.