Research evaluating the impacts of smart growth, new urbanism, and pedestrian oriented design on transportation, public health and community life is limited by weaknesses of conventional urban form measures. A review of recent literature finds standard measures, such as development density and land use, do not sufficiently differentiate basic elements of neighborhood form. This contributes to ambiguous research findings. Improved methods for operationalizing urban form as an independent variable is a critical need for the emerging field of urban design.

This dissertation explores the potential of developing simple, replicable measures that can better distinguish first order differences between neighborhoods. The complex nature of three dimensional space and a lack of useable datasets at this scale suggested an exploratory, hypothesis generating, research approach. The project is built around detailed study of a dozen neighborhoods in the Upper Valley Region of Vermont and New Hampshire. An extensive field based analysis of urban form identified key urban form variables and speculated on associations with perceived qualities of the neighborhood environment. Based on those findings, a GIS based, parcel-level data set was compiled at two scales of analysis neighborhood-wide and the more detailed realm of the street, block, lot, and building. The database was the basis for exploratory derivation and testing of simple replicable measures of neighborhood form. A field based survey tour established a perceptual baseline for a series of environmental qualities across the case studies. Correlating mean survey scores with calculated values served as a basic validity test for experimental measures.

Initial findings suggest both substantial limitations and promising areas of research related to developing quantitative measures of city form. The complexity of the built environment limited successful measures to very simple constructions based on the standard density measure of units per acre such as parcels per acre, buildings per parcel, or simple ratios such as building height to setback. Correlations of measured and perceived values offered insights into the relationship between urban form and environmental qualities. For qualities such as density, connectivity, and enclosure, the associated physical dimensions were generally clear and relatively easy to measure. Physical relationships associated with other qualities such as grain, scale, consistency and permeability, are more complex but certain classes of measures seemed to capture much of the observed variation between cases. Others, such as variability, are so complex that they seem best approached, at least initially, through use of proxy measures. Opportunities for future research include testing measures across a broader context of urban form and density and operationalizing measurement protocols within a GIS framework.

This dissertation uses theories of ethno-racial competition, boundary work, and collective action to explain the variable mobilization of collective ethnic violence against indigenous peoples in early American California, ca. 1850-1865. To do so, the dissertation proceeds through three chapters. The first chapter, “American Settler Colonialism, Racial Formation, and Competition Theory,” provides a theoretical framework that supports the empirical inquiries in the subsequent two chapters. To develop this framework, I draw from the American settler colonialism, collective action, ethnic competition, and mass violence and atrocities literatures to suggest new directions for the study of settler-colonial (i.e. inter-polity) intergroup competition and conflict. The second chapter provides a regional analysis of the dynamics of collective ethnic violence against indigenous peoples in central and northern California, ca. 1850-1865. This chapter focuses on the role of frame disputes as a mediating mechanism in intergroup conflicts. The central theoretical claim, which finds strong support, is that frame disputes among settlers in different California regions influenced the dynamics of collective violence by attributing different levels of collective out-group “threats” to proximate indigenous groups. As in contemporary cases, this ethno-racial polarization and subsequent violence was produced by the explicit attempts of local political actors to durably politicize ethno-racial group membership. The third empirical chapter looks more closely at the mechanisms supporting varying annual levels of collective ethnic violence against indigenous peoples in the Humboldt Bay region of California, ca. 1853-1865. This chapter continues my emphasis on framing and boundary work mechanisms as mediators of collective conflicts, while focusing my theoretical attention more squarely on issues of threat assessment, or the ways in which group-based threats are collectively appraised by nominal power-holding group members. Drawing from theories of mediated competition, I demonstrate the specific necessity of organizational resources for extremist mobilization, and that elite framing and boundary work were required to link aggrieved individuals with these mobilizing resources. These findings confirm the role of framing and associated boundary work mechanisms in the politics of collective threat assessment. To conclude, I discuss the implications of these threat assessment issues for future historical and contemporary study of reactive mobilization.

On September 14, the editors of the Berkeley Planning journal met with eight professionals and scholars to discuss a body of work we called "the new urbanism." This design movement has captured the attention of public officials, planners and citizens alike in recent years. We asked the participants to read at least two of four influential books and a recently published critique, to serve as a touchstone for the discussion; the result was a far-ranging discourse on the promise, pitfalls, and politics of urban planning and design in the 1990s. The participants brought very distinct concerns and first-hand experiences to the table. While agreeing that the new urbanism offered a much­ needed step in the right direction, they divided on whether its ideas, as now articulated, speak to the systems and attitudes that shape and divide suburban and urban communities today. Overall, we believe the participants pushed the discussion of this new movement onto

important ground.