Massachusetts is trying to force Boston suburbs to lift single family restrictions. Great intention, though i have feeling each town is going to fight for years against it.
It's not compulsory and it's not lifting, only requiring multifamily zoning around transit catchment areas. Towns that refuse to implement it lose out on state funding meaning the wealthy towns are free to ignore it. Perversely, those towns will now cost even more to live in because they need to offset the lost state money.
https://www.mass.gov/info-details/multi-family-zoning-requir...