In The Death and Life of Great American Cities Jane Jacobs is concerned with the problems of city planning and the strategy that planners followed in the year of 1961. Jacobs provides a good analysis of what contributes to the success of neighborhoods by looking at city streets and sidewalks, parks and neighborhoods. She explained that the street is the essential public space of a city providing safety and also allows for a healthy level of informal human contact, balancing between the need for privacy and the need for community. A high ratio of adults and enough sidewalk space allows children to play freely, relieves some of the burdens and costs of parenting. Small parks can benefit an already vibrant neighborhood, but they must fit their context. Out of place or excessively large parks interrupt street life and denigrate its safety. Underused parks can be redeemed by specializing in a certain service or activity. It is most effective, politically and socially, to consider cities in three senses: as whole cities, as neighborhoods, and as districts, each with different needs and strategies. Jacobs argued that urban renewal did not respect the needs of most city-dwellers. Jacobs is well known for organizing grassroots efforts to protect existing neighborhoods from, "slum clearance," and particularly for her opposition to Robert Moses in his plans to overhaul her neighborhood of Greenwich Village. She is responsible for the eventual cancellation of the Lower Manhattan Expressway, which would have passed directly through Washington Square Park, and was arrested in 1968 for inciting a crowd at a public hearing on the project.