Integrated Transportation & Land Use

Policymaking Should Consider the Time-dependent Greenhouse Gas Benefits of Transit-oriented Smart Growth

Transportation Research Record, Volume and Issue Forthcoming.

Proceedings of the 2015 Transportation Research Board 94th Annual Meeting (Paper 15-0254)

Cities are increasingly developing greenhouse gas (GHG) mitigation plans and reduction targets based on a growing body of knowledge about climate change risks, and changes to passenger transportation are often at the center of these efforts. Yet little information exists for characterizing how quickly or slowly GHG emissions reductions will accrue given changes in urban form around transit, and whether benefits will accrue quickly enough to meet policy year targets (such as reaching 20% of 1990 GHG emissions levels by 2050). Even more complicated is when cities focus on achieving GHG reductions through integrated transportation and land use planning, as changes in emissions can occur across many sectors (such as transportation, building energy use, and electricity generation). Using the Los Angeles Expo line, a framework is developed to assess how financing schemes change the rate of redevelopment and resulting life-cycle GHG emissions from travel and building energy use. The framework leverages an integrated transportation and land use life-cycle assessment model that captures upfront construction of new development near transit and the long-term changes in household energy use for travel and buildings. The results show that for the same amount of development around the Expo line it is possible to either meet (if aggressive redevelopment happens early) or not meet (if redevelopment starts decades out) state GHG goals by 2050. The time-based approach reveals how specific redevelopment schedules are needed for a city to reduce GHG emissions at a rate that meets future targets.

Expected 2015 Matthew Nahlik and Mikhail Chester ITLU

Transit-oriented smart growth can reduce life-cycle environmental impacts and household costs in Los Angeles

Transport Policy, 2014, 35, pp.21-30, doi: 10.1016/j.tranpol.2014.05.004.

The environmental and economic assessment of neighborhood-scale transit-oriented urban form changes should include initial construction impacts through long-term use to fully understand the benefits and costs of smart growth policies. The long-term impacts of moving people closer to transit require the coupling of behavioral forecasting with environmental assessment. Using new light rail and bus rapid transit in Los Angeles, California as a case study, a life-cycle environmental and economic assessment is developed to assess the potential range of impacts resulting from mixed-use infill development. An integrated transportation and land use life-cycle assessment framework is developed to estimate energy consumption, air emissions, and economic (public, developer, and user) costs. Residential and commercial buildings, automobile travel, and transit operation changes are included and a 60-year forecast is developed that compares transit-oriented growth against growth in areas without close access to high-capacity transit service. The results show that commercial developments create the greatest potential for impact reductions followed by residential commute shifts to transit, both of which may be effected by access to high-capacity transit, reduced parking requirements, and developer incentives. Greenhouse gas emission reductions up to 470 Gg CO2-equivalents per year can be achieved with potential costs savings for TOD users. The potential for respiratory impacts (PM10-equivalents) and smog formation can be reduced by 28–35%. The shift from business-as-usual growth to transit-oriented development can decrease user costs by $3100 per household per year over the building lifetime, despite higher rental costs within the mixed-use development.

May 2014 Matt Nahlik, Mikhail Chester ITLU, los angeles

Integrating Life-cycle Environmental and Economic Assessment with Transportation and Land Use Planning

Environmental Science & Technology, 2013, 47(21), 12020-12028, doi: 10.1021/es402985g.

The environmental outcomes of urban form changes should couple life-cycle and behavioral assessment methods to better understand urban sustainability policy outcomes. Using Phoenix, Arizona light rail as a case study, an integrated transportation and land use life-cycle assessment (ITLU-LCA) framework is developed to assess the changes to energy consumption and air emissions from transit-oriented neighborhood designs. Residential travel, commercial travel, and building energy use are included and the framework integrates household behavior change assessment to explore the environmental and economic outcomes of policies that affect infrastructure. The results show that upfront environmental and economic investments are needed (through more energy-intense building materials for high-density structures) to produce long run benefits in reduced building energy use and automobile travel. The annualized life-cycle benefits of transit-oriented developments in Phoenix can range from 1.7 to 230 Gg CO2e depending on the aggressiveness of residential density. Midpoint impact stressors for respiratory effects and photochemical smog formation are also assessed and can be reduced by 1.2–170 Mg PM10e and 41–5200 Mg O3e annually. These benefits will come at an additional construction cost of up to $410 million resulting in a cost of avoided CO2e at $16–29 and household cost savings.

November 2013 Mikhail Chester, Matt Nahlik, Andrew Fraser, Mindy Kimball, Venu Garikapati ITLU, Phoenix

Assessing the Potential for Reducing Life-Cycle Environmental Impacts through Transit-Oriented Development Infill along Existing Light Rail in Phoenix

Journal of Planning, Education, and Research, 2013, 33(4), 395-410, doi: 10.1177/0739456X13507485.

There is significant interest in reducing urban growth impacts yet little information exists to comprehensively estimate the energy and air quality tradeoffs. An integrated transportation and land-use life-cycle assessment framework is developed to quantify the long-term impacts from residential infill, using the Phoenix light rail system as a case study. The results show that (1) significant reductions in life-cycle energy use, greenhouse gas emissions, respiratory, and smog impacts are possible; (2) building construction, vehicle manufacturing, and energy feedstock effects are significant; and (3) marginal benefits from reduced automobile use and potential household behavior changes exceed marginal costs from new rail service.

December 2013 Mindy Kimball, Mikhail Chester, Janet Reyna, Christopher Gino itlu, Phoenix

Transit-Oriented Development Deployment Strategies to Maximize Integrated Transportation and Land Use Life Cycle Greenhouse Gas Reductions

ISSST, 2013, doi: 10.6084/m9.figshare.805094

Urban sustainability decision makers should incorporate time-based impacts of greenhouse gas emissions with life cycle assessment to improve climate change mitigation strategies. As cities develop strategies that move development closer to transit systems and encourage households to live in lower energy configurations, new methods are needed for understanding how upfront emissions of greenhouse gases produce long run radiative forcing impacts. Using an existing assessment of the development potential around Phoenix’s new light rail system, a framework is developed for deploying higher density, lower energy use, and more transit-friendly households near light rail given financing constraints. The case study compares development around transit stations in Phoenix against continued outward growth of single family homes. Using this case study, the significance of greenhouse gas (GHG) radiative forcing discounting is assessed. The radiative forcing benefits of different levels of financing aggressiveness are shown. A comparison of payback on upfront construction impacts for long run benefits is developed between the GHG accounting approach and the radiative forcing approach, the latter of which accounts for time-based GHG impacts. The results show that the radiative forcing approach puts more weight on upfront construction impacts and pushes the payback on initial investments out further than when GHG accounting is used. It is possible to reduce this payback time by providing a larger upfront financing resource. Ultimately, policy and decision makers should use radiative forcing measures over GHG measures because it will provide a measure that discounts GHG emissions at different times to a normalized unit.

September 2013 Mikhail Chester, Dwarakanath Ravikumar ITLU, Phoenix