The oil shortages and price rises of the 1970s led to a broad spectrum of policies designed to save fuel in transport. One such group of policies concentrated on utilising the longstanding observation that congestion-free driving improves vehicular fuel economy. In particular, improving the average speed of urban traffic was believed to reduce urban fuel use. Strategies to create free-flowing traffic networks through traffic engineering and management techniques became an integral part of most transport energy conservation strategies. At the same time urban systems studies were appearing which suggested that urban land use factors are fundamental in determining transport energy demand. Some cities with denser, more centralised developnent patterns and congested traffic systems appeared to have lower per capita transport energy use than cities with low density, dispersed land use and free-flowing traffic networks. Conflicts thus began to be recognised between these land use studies and the traffic studies but they were never systematically examined. This thesis focuses on explaining and attempting to resolve these apparent conflicts by drawing out the relative importance of freeflowing, fuel efficient traffic and broader land use/transport factors in determining urban system fuel efficiency. It does this by showing how a holistic understanding of transport energy use can be achieved by recognising the different levels of know1edge involved and by integrating research a t all these levels. Adopting this approach, a detailed examination is made of transport energy use in Perth, Western Australia. Spatial and temporal patterns of urban driving and vehicular fuel consumption are derived using a computer-instrumented vehicle within a framework of urban ecology. These patterns are described in detail and are found to be understandable in terms of a simple model of intersection and vehicle-based traffic events. Using this simple model, urban driving and fuel consumption patterns are then systematically linked back to their urban ecological framework. Centrality, as expressed by urban activity intensity emerges as the major underlying factor in both the urban ecological framework and driving patterns. Driving cycles for central to outer areas as well as the whole city are produced and a detailed examination is made of driving cycle development procedures, including the issue of data resolution. Two new methods of driving cycle synthesis are formulated. Driving cycles together with travel survey and land use/transport model data are then used to estimate spatial differences in transport energy use per capita within the urban ecological framework. This case study is used to test two conceptual models of transport energy conservation implied by the traffic and land use studies: a linear assumptions model which suggests reductions in urban system fuel use through freer-flowing traffic and a feedback assumptions model which introduces some possible broader system effects of free-flowing and congested traffic. The results suggest very strong support for the feedback model and a reversal of the linear model. Urban structural factors such as distance from the CBD and density are found to be the major explanatory factors of Perth's transport energy use. The much higher vehicular fuel consumption in Perth's inner areas due to restricted traffic flows are completely offset by energy conserving land use and transport features which result in lower per capita energy use in these areas; the lower vehicular fuel consumption in uncongested outer areas is swamped by land use factors which result in longer travel distances and less use of energy conserving modes, resulting in markedly higher per capita energy use, i .e. a trade-off is found between a fuel efficient traffic system and a fuel efficient urban system. It is concluded that policies which propose fuel savings from "blanket" improvements in urban trraffic flow, such as major road building programmes will be counter-productive, while urban planning policies which encourage higher density, more compact cities will tend to lower energy use. It is suggested that a key area of research is now how to combine selective traffic system improvements with urban land use policies so that both may work in concert to produce a more fuel efficient urban system.

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The sprawl of U.S. cities has attracted criticism from many sources in recent years. Among the greatest of the cited harms of sprawl is the alleged travel time burden that it imposes on its residents. Previous research has tested the relationship between the sprawl of business activity and travel times by examining only its effects on commuting times and has concluded that people do not choosing housing and work locations to minimize commutes. This research takes a more comprehensive approach by analyzing the relationship between household travel times and sprawl by testing the relationship between access to economic centers and daily household travel time. The relatively minor increase in household travel times with decrease in access to economic centers found by the analysis shows that people logically reduce trips to centers when choosing housing locations with less access to centers. The ability of people to make these reductions in travel is clearly increased by the dispersal of activity from the central business district and other centers. Comparison of predicted household travel times with an estimated rent gradient show that the increase in housing prices with improved access to subcenters is far less than would be expected given the predicted household travel times, contradicting the relationship between household travel time and housing prices embodied in central place theory and its limited polycentric extensions. An analysis of joined trips suggests that households with less access to economic centers used joined trips, in which multiple destinations are visited on a single trip from the home, to reduce household travel. All of the results suggest that auto use enables households throughout the metropolitan area to reduce travel time. The car has greater flexibility and speed than other modes, particularly in areas of lower density. The travel time savings and flexibility that are provided by the dispersal of economic activity have allowed people to choosing housing that they prefer at lower prices with little added transportation cost. Given these benefits we should carefully consider the manner and method we choose to reduce any negative externalities of sprawl and auto use. / Ph. D.

Staden som en handelsplats har djupa rötter och handelns form i våra städer förändras löpande, i samtiden kanske framförallt genom e-handelns intåg. Arenan för kommersiell service är i ständig förändring och när våra städer förtätas har vi genom planering chans att påverka förutsättningarna för kommersiell service. Föremålet för denna studie är förhållandet mellan densitet, service och urban form. Sambandet mellan densitet och urban kommersiell ställs mot en integrationsanalys enligt space syntax för att identifiera om olika områdens urbana form påverkar tillgången till urban kommersiell service. Genom fallstudier av Stockholm och Göteborg visar uppsatsen att över- och underrepresentation av urban kommersiell service i förhållande till befolkningsdensiteten framförallt förekommer i de centrala delarna av staden, men underrepresentation oftare i anslutning till större barriärer. Områden med höga integrationsvärden kan i studiens båda fall kopplas till en stor överrepresentation av kommersiell service.

A large proportion of energy demand comes from urban areas, mostly from buildings and transport, the use of which has impacts on climate and air quality through the emissions of greenhouse gases and other pollutants. To effectively mitigate these impacts, a better understanding of the relationship between energy and urban form variables is crucial. The link between energy and urban variables has been demonstrated before and it is recognised in many aspects of the cities, such as human behaviour and transport dynamics. This research goes forward by analysing the correlation and scaling between energy consumption and different land use typologies derived from urban form variables, as well as at other scales. The work is built on readily available datasets for England to guarantee the replicability of the methodology and ensure the reliability of the results. A combined energy use metric integrating buildings and commute transport produces helpful insights into energy consumption patterns and it is obtained at a large geographic scale. The identification of local scale consumption patterns is attractive to policymakers and planners by providing them detailed information to direct local-level policies. On the other hand, the derived land use typologies deliver new knowledge about the spatialisation of the urban system and to establish the link with the energy use. The results reveal that the relationship between energy and urban variables favours the application of compact city to reduce carbon-based energy consumption. This means that better energy efficiency is achieved by areas with higher population density. The analysis also shows that socio-economic variables have higher impact on energy consumption than physical variables. Moreover, differences at city scale and for the land use typologies are identified, demonstrating the importance of focusing the analysis according to the goal. In sum, the results from this work provide new insights about the relationship between energy and urban characteristics that can be used by policymakers and planners to outline more focused and detailed actions to mitigate energy use in England.

As residential urban development increases in the western United States, few studies have shown how different urban forms influence vegetation cover. The two studies in this thesis examine how to define and measure urban form in order to understand the relationship between urban form characteristics and vegetation cover. In the first study, urban form was defined by using past methods of identifying and measuring urban sprawl. Past studies showed the most essential metrics that define residential urban form are building density, centrality, connectivity, land use mix, and parcel size. This study reviews these metrics and proposes revised unified definitions and measurement methods. It is recommended that consistent definitions and methods be used in further research of urban form. Cache County, Utah was used as a study area to apply these methods as a representative community of the western U.S. Residential parcels were measured for each metric. A K-means cluster analysis assign each parcel to one of 50 groups based on metric measurement similarities. The 10 most widely used groups contained 87% of the residential parcels in Cache County. These groups represented urban forms with distinct identifiable characteristics such as Agricultural residential, urban sprawl, historic plat patterns, and evolved versions each. The second study used the metrics and groups from the first study to check for correlations with vegetation cover. A normalized difference vegetation index ( NDVI) of aerial imagery of Cache County was used to classify land cover into three groups: dense vegetation, light vegetation, and no vegetation. Measurements of vegetation cover were extracted for each parcel and each urban form group. Total vegetation cover ( TVC) and dense vegetation cover (DVC) measured higher in urban areas than in the county as a whole. Agricultural residential groups had among the highest TVC, but had the lowest DVC. Non-agricultural residential groups had the highest DVC as a percentage of TVC with the exception of group 4 “Modern Suburban Sprawl” which had the lowest DVC as a percentage of TVC. Group 7 “Satellite Centers” had the highest TVC while group 3 “Dead End Semi-sprawl” had the lowest TVC. Both groups 3 and 7 had the highest DVC as a percentage of TVC. A correlation analysis revealed that TVC had stronger correlations than DVC with urban form metrics. Building density had the strongest correlation with TVC (r = -0.62, p= 0). Correlations with TVC were also found with Parcel size (r = -0.23, p= <.001) and centrality (r = -0.21, p = <.001). Very weak relationships with TVC w ere found with connectivity and land use mix.

Conventional transportation demand management approaches have had limited success in reducing automobile dependency. As a result, it has become increasingly important to understand the decision-making processes involved in determining travel behaviour. The purpose of this dissertation is to extend research on urban form and travel behaviour beyond adult travel by examining teen travelers aged 13-19 in the Greater Toronto Area. Data from the Transportation Tomorrow Survey (TTS) survey are used to study four main research questions: 1) How has teen mode choice changed from 1986 to 2006? 2) How do these choices vary as teens transition from the 13-15 age group to being of driving age (16-19)? 3) How do these choices vary across the different urban and suburban regions of the GTA? 4) What are some of the differences between teen travel and adult travel? The issue is further probed through the collection of quantitative and qualitative travel data from first year students at the University of Toronto, and a series of focus groups held in locations in the GTA. The first year survey explores attitudes towards different modes in relation to the locational attributes of the respondent‘s hometown neighbourhood. The focus group sessions involve interviews with 26 teen and a take-home parental questionnaire. Results show that across the GTA, active transportation has decreased while auto passenger mode shares have increased. Younger teens walk more and older teens take transit more for both school and discretionary travel. Jurisdictions with better transit supply and orientation have higher transit mode shares for school trips, but discretionary trips have low transit mode shares. Walk mode shares for both school and discretionary travel are similar across all jurisdictions, regardless of whether they are urban or suburban. Additionally, the survey participants' narratives illustrate that the desire to travel actively and independently is strong. However, the reality of the final travel choice is determined by the presence of supportive infrastructure that facilitates active mode choices while shaping perceptions and attitudes formed as a result of daily travel experiences. Findings illustrate the relevance of qualitative work in advancing transportation research--particularly in understanding human travel decisions.

Conventional transportation demand management approaches have had limited success in reducing automobile dependency. As a result, it has become increasingly important to understand the decision-making processes involved in determining travel behaviour. The purpose of this dissertation is to extend research on urban form and travel behaviour beyond adult travel by examining teen travelers aged 13-19 in the Greater Toronto Area. Data from the Transportation Tomorrow Survey (TTS) survey are used to study four main research questions: 1) How has teen mode choice changed from 1986 to 2006? 2) How do these choices vary as teens transition from the 13-15 age group to being of driving age (16-19)? 3) How do these choices vary across the different urban and suburban regions of the GTA? 4) What are some of the differences between teen travel and adult travel? The issue is further probed through the collection of quantitative and qualitative travel data from first year students at the University of Toronto, and a series of focus groups held in locations in the GTA. The first year survey explores attitudes towards different modes in relation to the locational attributes of the respondent‘s hometown neighbourhood. The focus group sessions involve interviews with 26 teen and a take-home parental questionnaire. Results show that across the GTA, active transportation has decreased while auto passenger mode shares have increased. Younger teens walk more and older teens take transit more for both school and discretionary travel. Jurisdictions with better transit supply and orientation have higher transit mode shares for school trips, but discretionary trips have low transit mode shares. Walk mode shares for both school and discretionary travel are similar across all jurisdictions, regardless of whether they are urban or suburban. Additionally, the survey participants' narratives illustrate that the desire to travel actively and independently is strong. However, the reality of the final travel choice is determined by the presence of supportive infrastructure that facilitates active mode choices while shaping perceptions and attitudes formed as a result of daily travel experiences. Findings illustrate the relevance of qualitative work in advancing transportation research--particularly in understanding human travel decisions.

This thesis presents evidence that income polarization is accompanied by increasing social-spatial disparities between areas of the city that were developed in different societal contexts, with different planning approaches, and that have different land use and transportation dynamics. An analysis of the social structure of the Toronto Metropolitan Area finds indications of widespread gentrification in the inner city, socioeconomic decline in the postwar suburbs, and sustained household affluence in the ever expanding outermost suburbs of the metropolitan area. It is argued that, as a political and social endeavor that is embedded in broader development regimes, urban planning influences social-spatial polarization to the extent that it influences urban form.