'Tactical urbanism': The guerrillas from the planning department
According to Wikipedia, 'tactical urbanism', also commonly referred to as 'guerrilla urbanism', 'pop-up urbanism', 'city repair', 'D.I.Y. urbanism', 'planning-by-doing', 'urban acupuncture', and 'urban prototyping', is a low-cost, temporary change to the built environment, usually in cities, intended to improve local neighborhoods and city gathering places. It is often citizen-led but can also be initiated by government entities. Community-led temporary installations are often intended to pressure government agencies into installing a more permanent or expensive version of the improvement.
In this case, the guerrilla warriors from the city of Middleton's 'planning and community development department' have installed a traffic circle at the intersection of Elmwood Avenue and Middleton Street, and narrowed the roadway on Elmwood Avenue mid-block between Bristol Street and Park Street by 'bulbing out' the curb (both pictured).