Lexington has a propensity to develop properties at the very edge of the Lexington town line. A "memory care " facility was recently opened next to the Belmont Country Club. Avalon at Lexington Hills repurposed the old Met State hospital next to Waltham (Waltham has chosen to preserve as open space the part of Met State that falls within their boundary). There is another Avalon on Waltham St. in Lexington and a massive (31 acres) new complex called Brookhaven, an assisted living facility literally across the street from Avalon. The traffic problems are obvious. Lexington could prevent this development if it were inclined to do so. By contrast, a solar farm is mostly passive.