D2. Transport, technology and carbon reduction

Integrating transport and urban design strategies

Aims and method:

Explores how the Density, Diversity and Design (DDD) model of urban development may be combined with the Avoid, Shift, Improve and Finance (ASIF) model of transport to reduce CO2 emissions and Vehicle Kilometres Travelled (VKT). Using a workshop comprised of designers, planners, politicians, and students, three scenarios – 1) business as usual (car focused), 2) increased rapid bus transport, and 3) light rail – for a new development in Perth, Australia were audited.

Key Findings:

· The rapid bus and light rail options showed significant (45-48%) reductions in carbon emissions, despite large construction requirements for light rail

· The light rail option was rated more highly in terms of its positive impact on place-making

Reference:

Tiwari, R., Cervero, R., & Schipper, L. (2011). Driving CO2 reduction by integrating transport and urban design strategies. Cities, 28(5), 394-405.

http://www.sciencedirect.com/science/article/pii/S0264275111000606

Low-carbon urban transport and land uses

Aims and method:

Classifies and examines a range of low-carbon transport strategies in the context of different urban development and land use regimes. Thirteen carbon-reduction approaches (a mix of design and economic interventions) across three strategies (SHIFT, IMPROVE, AVOID) were evaluated to identify optimal strategies in developed and developing cities.

Key Findings:

· AVOID and SHIFT strategies are significantly affected by land use.

· Design changes such as encouraging density, transit oriented development and transit corridor development coupled with economic interventions such as road pricing may significantly reduce CO2.

· IMPROVE strategies rely principally on technological interventions, such as emissions reduction and transport integration.

Reference:

Nakamura, K., & Hayashi, Y. (2013). Strategies and instruments for low-carbon urban transport: an international review on trends and effects. Transport Policy, 29, 264-274.

http://www.sciencedirect.com/science/article/pii/S0967070X12001187

Generating sustainable form-based strategies

Aims and method:

Examines which form-based urban design strategies can most effectively deliver greater environmental, social, and economic coherence in Dubai's neighbourhood development. Using two-rounds of a Delphi questionnaire (n=129, 61% response rate), the opinions of planners, designers, and academics with ties to the region were gathered and reviewed.

Key Findings:

· The majority of respondents (n=32) advocated compact development focused on densification (a variety of density levels), proximity (closeness of housing to work, services, and amenities), diversity, and urban infill/intensification.

· While cultural and institutional issues make implementation of these strategies difficult in the setting of Dubai, the benefits of transitioning from urban sprawl to more compact designs are substantial, notably: reduction in infrastructure and service expenses; reduced heat gain and cooling load during daytime hours; and facilitating passive cooling strategies

· Findings stress that for Dubai, the most sustainable neighbourhoods will feature compactness, connectivity and multiple transportation options, diversity, culturally relevant urbanism, and climate-sensitive urbanism, all integrated in the urban fabric

Reference:

Alawadi, K. (2017). Rethinking Dubai's urbanism: Generating sustainable form-based urban design strategies for an integrated neighborhood. Cities, 60, 353-366.

http://www.sciencedirect.com/science/article/pii/S0264275116301433

Housing form and energy use

Aims and method:

Examines the relationship between urban form (land use characteristics) and household energy demand for space heating. The study employs a two-step quantitative model. First, heating energy demands were calculated for different residential dwellings based on the thermal balance model. Second, the spatial distribution of energy demand of residential settlement patterns was specified using the MOLAND model.

Key Findings:

· Domestic energy use is sensitive to four land use characteristics: 1) type; 2) age; 3) size of housing; 4) household density.

· Newer, smaller, apartments in denser built areas consume less energy.

Reference:

Liu, X., & Sweeney, J. (2012). Modelling the impact of urban form on household energy demand and related CO2 emissions in the Greater Dublin Region. Energy Policy, 46, 359-369.

http://www.sciencedirect.com/science/article/pii/S0301421512002753`

Mixed use, density and energy consumption

Aims and method:

Examines three issues in Xiamen, China: 1) settlement morphology and its transition process in rapidly developing cities; 2) the relationship between transport energy consumption and transition morphology; 3) the policies required to guide transportation technologies in developing settlement morphologies. Uses the TRANUS, an integrated transport-land use model, in which the interactions of activities, traffic, residents, and road network are quantitatively modelled to evaluate different scenarios.

Key Findings:

· Mixed-use developments with greater density lead to lower transportation energy consumption.

· Integrating public transportation into mixed-use, denser developments has the greatest role in reducing energy consumption.

Reference:

Zhou, J., Lin, J., Cui, S., Qiu, Q., & Zhao, Q. (2013). Exploring the relationship between urban transportation energy consumption and transition of settlement morphology: A case study on Xiamen Island, China. Habitat international, 37, 70-79.

http://www.sciencedirect.com/science/article/pii/S0197397511001056

Carbon reducing technologies and urban form

Aims and method:

Models the impact of three different urban forms (high density centralised, medium density averaged, low density de-centralised) and the installation of two potential greenhouse gas reducing technologies (photovoltaic cells and combined heat and power technologies) on predicted emissions in 2030 and 2050 in Utsunomiya City, Japan.

Key Findings:

· Technological interventions drove greenhouse gas reductions in developments, with land use showing little impact.

· Medium averaged density developments provide the greatest opportunity for combining photovoltaic cells and combined heat and power technologies and reducing greenhouse gas emissions.

Reference:

Ishii, S., Tabushi, S., Aramaki, T., & Hanaki, K. (2010). Impact of future urban form on the potential to reduce greenhouse gas emissions from residential, commercial and public buildings in Utsunomiya, Japan. Energy Policy, 38(9), 4888-4896.

http://www.sciencedirect.com/science/article/pii/S0301421509006090

CO2 emissions in megacities

Aims and method:

Evaluates the impacts of socioeconomic factors, urban form and transportation networks on CO2 emissions in four Chinese megacities (Beijing, Shanghai, Tianjin and Guangzhou). Uses the SPIRPAT model to quantitatively evaluate the relationship between the different factors.

Key Findings:

· Rapid urbanisation has led to rapid rises in C02 emissions

· Improvements in energy saving technology, technological know-how and management capacity are required to reduce emissions.

· Reductions in urban sprawl (increasing compactness) and more integrated public transportation networks are crucial to reducing CO2 emissions.

Reference:

Wang, S., Liu, X., Zhou, C., Hu, J., & Ou, J. (2017). Examining the impacts of socioeconomic factors, urban form, and transportation networks on CO2 emissions in China’s megacities. Applied Energy, 185, 189-200.

http://www.sciencedirect.com/science/article/pii/S0306261916314957