The organization has collaborated with many major institutions to improve the appearance and functionality of public spaces throughout the United States. In 2005, PPS co-founded The New York City Streets Renaissance, a campaign that worked to develop a new campaign model for transportation reform. This initiative implemented the transformation of excess sidewalk space in the Meatpacking District of Manhattan into public space. Also, by 2008, New York City reclaimed of traffic lanes and parking spots away from cars and gave it back to the public as bike lanes and public plazas. The Center for Human Environments at the CUNY Graduate Center is a research organization that examines the relationship between people and their physical settings. CHE has five subgroups that specialize in aiding specific populations: The Children's Environments Research Group, the Health and Society Research Group, the Housing Environments Research Group, the Public Space Research Group, and the Youth Studies Research Group. The most relevant scientific groups are the International Association of People-Environment Studies (IAPS) and the Environmental Design Research Association (EDRA). Urban Ecology , The Urban Ecologist, and the International Eco-City Conference were some of the first collectives to establish the idea of eco-cities and townships. Challenges The field saw significant research findings and a fair surge of interest in the late 1970s and early 1980s, but has seen challenges of nomenclature, obtaining objective and repeatable results, scope, and the fact that some research rests on underlying assumptions about human perception, which is not fully understood. Being an interdisciplinary field is difficult because it lacks a solid definition and purpose. It is hard for the field to fit into organizational structures. In the words of Guido Francescato, speaking in 2000, environmental psychology encompasses a "somewhat bewildering array of disparate methodologies, conceptual orientations, and interpretations... making it difficult to delineate, with any degree of precision, just what the field is all about and what might it contribute to the construction of society and the unfolding of history." A grand challenge in the field of environmental psychology today is to understand the impact of human behavior on the climate and climate change. Understanding why some people engage in pro-environment behaviors can help predict the necessary requirements to engage others in making sustainable change. Environmental psychology has not received nearly enough supporters to be considered an interdisciplinary field within psychology. Harold M. Proshanksy was one of the founders of environmental psychology and