Her most influential work was The Death and Life of Great American Cities (1961), in which she harshly criticized the urban renewal practices of the 1950s in the United States, whose planners (urban planning, urban design) assumed ideal schematic models that according to her led to the destruction of public space. Using innovative and interdisciplinary scientific methods (coming from both social sciences and natural sciences), the author identified the causes of violence in everyday urban life, depending on whether it was subject to abandonment or, on the contrary, to good nutrition, security and quality of life.[38].
His ideas about the spontaneous self-organization of urban planning were applied in the later concept of emergent systems. As Marcelo Pisarro wrote), "contemporary urban paradigms (communal spaces, reduction in vehicular traffic, preservation of historical heritage, alternative means of transportation, local economies, recycling) have something of Jacobs' book, even in the negative, since she was also full of good intentions. The hell it caused, at least in Greenwich Village, was residential elitization: gentrification turned the neighborhood into one of the most expensive and exclusive in the United States.
In addition to his literary work, Jacobs stood out for his activism in the organization of social movements self-defined as spontaneous (grassroots), aimed at paralyzing urban projects that he understood to be destroying local communities. First in the United States, where he achieved the cancellation of the Lower Manhattan Expressway; and later in Canada, where he emigrated in 1968 and where he achieved the cancellation of the Spadina Expressway")[39] and the network of highways that were intended to be built.[40].
Jacobs is credited, along with Lewis Mumford, with inspiring the New Urbanism movement.[41] She discussed her legacy in an interview with Reason magazine "Reason (magazine)").
Expansion and development are two different things. Development is the differentiation of what already existed. Virtually everything new that happens is a differentiation from an old thing, from a new shoe sole to changes in legal codes. Expansion is real growth in size or volume of activity. That's something different.
I have done it two different ways. A long time ago, when I wrote The Economy of Cities, I wrote about import substitution and how that expands, not only the economy of the place where it occurs, but also economic life in general. As a city replaces imports, it displaces its imports. It doesn't matter less. And yet it has everything it had before.
While Jacobs saw his greatest legacy as his contribution to economic theory, it is in the realm of urban planning that he has had his greatest impact. Her observations about the ways in which cities function revolutionized the urban planning profession and discredited many accepted planning models that dominated mid-century planning.[42] Economist Edward Glaeser, known for his work in urban studies, acknowledged that Jane Jacobs (1960) had been prescient in attacking Moses for "replacing well-functioning neighborhoods with towers inspired by Le Corbusier." Glaeser agreed that these housing projects proved to be Moses' greatest failures, "Moses spent millions and evicted tens of thousands of people to create buildings that became centers of crime, poverty and despair."[43].
She was also famous for introducing concepts such as "eyes on the street", a reference to what would later be known as natural surveillance. The concept had a great influence on planners and architects such as Oscar Newman, who put the idea into practice through a series of studies that would culminate in his theory of defensible space. Jacobs and Newman's work would affect US housing policy through the HOPE VI Program, an effort by the US Department of Housing and Urban Development to demolish the high-rise public housing projects so maligned by Jacobs and replace them with low-rise mixed-income housing.
Throughout his life, he fought to change the way the city's development was approached. Arguing that cities were living things and ecosystems, he advocated ideas such as "mixed-use" development and bottom-up planning. Furthermore, his harsh criticism of "slum clearance" and "high-rise housing" projects were instrumental in discrediting these once universally supported planning practices.[44].
Jacobs is remembered as an advocate for the conscious development of cities and for leaving "a legacy of empowerment so that citizens trust their common sense and become defenders of their place."[45].
Although Jacobs focused primarily on New York, his arguments have been identified as universal.[46] For example, his opposition against the demolition of urban neighborhoods for urban renewal projects had "particular resonance" in Melbourne, Australia. In Melbourne in the 1960s, residents' associations fought against the Victorian Housing Commission's large-scale high-rise housing projects, which they argued had little regard for the impact on local communities.[47].
Jacobs fought an uphill battle against dominant planning trends even though the United States remains a suburban nation,[42] Jacobs' work has contributed to city life being rehabilitated and revitalized.