Quantifying Transit’s Impact on GHG Emissions and Energy Use—The Land Use Component (2015)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

5 S E C T I O N 1 1.1 Research Problem APTA’s Recommended Practice for Quantifying Greenhouse Gas Emissions from Transit (2009) describes three categories of emissions displaced by transit and provides methodologies for their quantification: • Avoided car trips through mode shift from private automobiles to transit (referred to as the ridership effect in this research or the direct effect of transit in some other studies). • Congestion relief benefits through improved operating efficiency of private automobiles, including reduced idling and stop-and-go traffic. • The land use multiplier, through transit enabling denser land use patterns that promote shorter trips, walking and cycling, and reduced car use and ownership (referred to as the land use effect in this research or the indirect effect of transit in some other studies). The key methodological question for the majority of greenhouse gas (GHG) emissions dis- placed is how much are vehicle miles traveled (VMT) reduced through both the ridership effect and the land use effect? A large body of research examines the effect of transit service on VMT, but most of the existing research focuses on ridership effects, whereby travelers shift from driving to riding transit. However, some studies have also shown that transit lines have effects on property values and community design that can lead to compact development, mixed uses, and more walk- able environments near transit stations, and research has linked these factors to reduced VMT. While the effect of urban form variables (such as density, land use mixing, and sidewalk cov- erage) on VMT is well studied, there is far less consistent information on how transit systems affect urban form. There is little research available evaluating how land use changes influenced by transit systems affect GHG emissions, and transit agencies lack guidance on how to consider these effects in the planning process and in calculating their aggregate effect on GHG emissions, energy use, and other environmental and economic impacts. 1.2 Project Scope and Objectives The overall objective of this project was to analyze the complex interrelationships between transit and land use patterns in a way that would help transit agencies to quantify and better understand their contribution to compact development and the resulting GHG reduction ben- efits. Specifically, the objectives of this project were to: • Develop a methodology to quantify the transportation-related GHG emissions and energy use related to land use changes that can be attributed to transit. The methodology developed shall quantify the impact of transit on land use and the resulting impact on transportation-related GHG emissions and energy use, and shall determine what portion of land use related impacts, and thus changes in transportation-related GHG and energy use, are attributable to transit. Introduction

6 Quantifying Transit’s Impact on GHG Emissions and Energy Use—The Land Use Component • Identify, describe, and, to the extent possible, quantify the synergistic interaction between transit and land use and the effects on transportation-related GHG emissions and energy use. The project accomplished all stated objectives, with one exception: quantification of the “syn- ergistic interaction between transit and land use,” meaning the mutually reinforcing aspects of transit service and compact urban forms. For example, transit stations that are located in areas with small block sizes and a good pedestrian environment may be more likely to attract compact development. The datasets and statistical models used in the research did not find evidence suf- ficient to quantify the synergistic relationships in detail. 1.3 Research Tasks The other tasks of the project were • Performing a review of the literature. A survey of current literature on the topic informed the premises of the research and key research questions. • Data collection. Extensive data collection provided the basis for statistical modeling. • Construction of statistical models. A series of statistical models was constructed to quan- tify the relationships between key transportation and land use variables at multiple geo- graphical scales. Best-fit models were selected based on broadly accepted goodness-of-fit measures. • Interpretation of model results. The models constructed were used to estimate the effects of transit service on land use patterns, VMT, energy, and fuel use. Estimates were adjusted, cross-validated, and compared to real world examples. • Development of the Land Use Benefit Calculator (“the calculator”). A calculator was devel- oped to allow individual regions or transit systems to estimate the effects of their existing systems or system enhancements on VMT, energy use, and GHG emissions. • Pilot testing and refinement of the calculator. Several transit agencies were engaged to test the tool, and their feedback was incorporated into a revised calculator. • Preparation of a final report. This final report communicates the research methods and find- ings and provides a user guide to accompany the calculator. 1.4 Research Applicability This report contains research and findings that will be useful to • Transit agencies. This research can help to quantify the benefits provided by their service and better understand the characteristics of transit service that contribute to more compact development. Land use benefits quantified in this study can be used as a regionally specific alternative to APTA’s national level land use multiplier. • Planners. This research can help to consider the likely land use developments associated with planned transit service and key variables that affect development activity. • Modelers. This research can inform elasticities used in land use models. • Researchers. This research can inform future research on the relationship between transit service and land use patterns. 1.5 Report Structure The sections in the remainder of this report are the following: • Section 2—Transit’s Impact on GHG Emissions and Energy Use: The Land Use Compo- nent defines the land use effect of transit in more detail and explains which effects of transit

Introduction 7 systems are captured in this research, including benefits in terms of VMT, energy, and GHG emissions reductions. • Section 3—Research Methodology summarizes the statistical methodology used. • Section 4—The Land Use Effect of Transit: Findings provides key findings of this research, with immediate implications for planners, drawing on the modeling exercises conducted. Key findings include benefits in terms of VMT, energy, and GHG emissions reductions. • Section 5—The Land Use Benefit Calculator: An Introduction provides an introduction to the calculator, which operationalizes key findings and estimates benefits in terms of VMT, energy, and GHG emissions reductions. • Section 6—The Calculator: User Guide and Case Studies provides a step-by-step user guide and case studies of the calculator’s use by transit agencies. • Section 7—Recommended Practice for Quantifying GHG Emissions from Transit discusses how the calculator can be applied to calculate GHG emissions displaced by transit for the purposes of a GHG inventory. • Section 8—Future Research provides suggestions for future research. • Appendix A and Appendix B provide full technical details of the modeling exercises conducted.