I want zoning reform for the higher density necessary to make those things viable.

(It also would vastly reduce the amount of concrete needed per capita, reducing CO₂ emissions from its manufacture, and would also reduce HVAC energy use because multifamily buildings with shared walls are more efficient than single-family homes with all 6 sides exposed to the environment.)

(Frankly, it’s amazing how many initially seemingly unrelated problems really boil down to bad zoning, once you follow the line of causation.)