Revise municipal zoning to allow for triplex and fourplex housing

SB 266 requires Montana cities with populations over 5,000 to allow triplexes (three-unit homes) and fourplexes (four-unit homes) in areas where single-family homes are permitted, without imposing stricter rules than those for single-family properties. The bill mandates that zoning regulations for these multi-unit housing types cannot be more restrictive than those for single-family residences, including limits on parking (max one space per unit) and reduced requirements for lot sizes or building setbacks. It also encourages local governments to adopt additional housing strategies, such as eliminating or reducing off-street parking mandates and permitting accessory dwelling units. This bill directly affects cities meeting the population threshold, aiming to increase housing density options for residents.