Autopia!

Not related to autsim but people with down syndrome have a town where there are nearly 50% of the population the whole enviroment is adjusted to there needs and the people there live very fuilling lifes as i understand it

the local servese are trailord to there need and are ran a lot cheaper then anywhere else in the country

https://en.wikipedia.org/wiki/Botton,_North_Yorkshire

https://www.camphillvillagetrust.org.uk/locations/botton-village/

their is another community in the usa in newyork

you also might find theses articals intresting

https://www.forbes.com/sites/michaelbernick/2019/06/26/the-autism-city-part-1-the-intentional-community/?sh=492d34ead482

https://embrace-autism.com/autism-friendly-towns/

I have given this some thought. Have you heard of land covenants? When you sell land you can make conditions on how the land is used. Provided the first buyer agrees to it these conditions are binding on all future owners.

you could in theory buy up a large city sized piece of countryside and sell off chunks to developers under a covenant that it can only be used as a residence if at least one resident is autistic. In effect you’d have an area in which every occupied house had to have at least one autistic person in it.

You could create a charitable trust who’s stated aim is the creating of a city for autistic people. It buys up the land in an out of the way place and applies for planing permission. Then create a not for profit housing association to develop parts of this land under covenant. Hopefully as the houses fill up other developers seek to build on the unused land with planing permission but if they want to do so they have to do it under covenant. 

You’d needs a phased approach. Start by building a village. Which is basicly a housing estate + some shops an the outline of the roads.

but planing wise you leave room for a city centre just to one side of the village. You leave corridors for train tracks, ring roads. Electricity pylons and utilities. Then after your village is well populated you sell off one or two other plots around the ‘empty’ city centre holding back the needed land for future infer structure. And you start building the roads and infer structure of the city centre and offering small plots  for development to become shoping centre's, cinemas etc.

the important thing is to always have a band of unused land around the developments in the early stage so no one else can buy it up land next to your development and build on it without covenant.

You’d needs a phased approach. Start by building a village. Which is basicly a housing estate + some shops an the outline of the roads.

but planing wise you leave room for a city centre just to one side of the village. You leave corridors for train tracks, ring roads. Electricity pylons and utilities. Then after your village is well populated you sell off one or two other plots around the ‘empty’ city centre holding back the needed land for future infer structure. And you start building the roads and infer structure of the city centre and offering small plots  for development to become shoping centre's, cinemas etc.

the important thing is to always have a band of unused land around the developments in the early stage so no one else can buy it up land next to your development and build on it without covenant.