From 1800 to 2000, cities grew enormously, and saw an expansion of public spaces to serve the varied needs of a diverse population living in ever more cramped and urban circumstances. While a wide range of commercial semipublic spaces became common in the late 19th century, parks and streets were the best examples of truly public spaces with full freedom of access. Changes in the design and management of streets, sidewalks, squares, parks, and plazas during this period reflect changing ideas about the purpose of public space and how it should be used.
Streets shifted from being used for a wide range of activities, including vending, playing games, and storing goods, to becoming increasingly specialized spaces of movement, designed and managed by the early twentieth century for automobile traffic. Sidewalks, which in the early nineteenth century were paid for and liberally used by adjacent businesses, were similarly specialized as spaces of pedestrian movement. However, the tradition of using streets and sidewalks as a space of public celebration and public speech remained strong throughout the period. During parades and protests, streets and sidewalks were temporarily remade as spaces of the performance of the public, and the daily activities of circulation and commerce were set aside.
In 1800, the main open public spaces in cities were public squares or commons, often used for militia training and public celebration. In the second half of the 19th century, these were augmented by large picturesque parks. Designed as an antidote to urbanity, these parks served the public as a place for leisure, redefining public space as a polite leisure amenity, rather than a place for people to congregate as a public. The addition of playgrounds, recreational spaces, and public plazas in the 20th century served both the physical and mental health of the public. In the late 20th century, responding to neoliberal ideas and urban fiscal crises, the ownership and management of public parks and plazas was increasingly privatized, further challenging public accessibility.
A New Domain for Public Speech: Opening Public Spaces Online