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Center for Climate-Smart Transportation


Current Projects

The Impacts of Mixed-Use Development (MXD) on Vehicle Miles Travelled (VMT) and GHG Emissions.

Principal Investigator(s): Simon C. Brewer PhD; Reid Ewing PhD; Shima Hamidi PhD

To help reach goals of improving air quality and reducing greenhouse gas emissions, recent legislation in California has required that the impacts of new developments are measured in vehicle miles traveled (VMT). The proposed research will address the mismatch between requirements and existing methods by establishing a predictive model of VMT for mixed-use developments (MXDs).

Climate change adaptation for active transportation: What are American cities doing?

Principal Investigator(s): Alessandro Rigolon PhD, Reid Ewing PhD

This project asks research questions about municipal climate adaptation for active transportation. 1. What types of climate adaptation strategies for active transportation are included in plans created by large U.S. cities? 2. How do these strategies consider environmental injustices related to active transportation and heat and seek to address them, if at all? 3. What barriers and opportunities do U.S. cities face when planning for climate adaptation for active transportation? 4. What strategies are used to implement climate adaptation provisions for active transportation?

The 15-minute city quantified using mobility data

Principal Investigator(s): Carlo Ratti PhD, Paolo Santi PhD

In response to social and environmental challenges faced by cities worldwide, policymakers are embracing the "15-minute city" planning model, positing that most human needs should be met within a short walk from home. Despite its rising popularity, there is currently no large-scale empirical evidence that can be used to measure exactly how aligned cities and neighborhoods are with the 15-minute vision and assess the distributional implications of advancing that vision. In this project, researchers introduce a new measure to quantify local trip behavior using GPS data from 40 million mobile devices across the US.

A Granular Characterization of Mobility-Related Air Pollution Exposure Disparity

Principal Investigator(s): Paolo Santi PhD, Carlo Ratti PhD, Simone Mora PhD

This project quantifies air pollution exposure using big mobility data on individual trips from more than 40 million mobile devices in the contiguous United States for the pre-pandemic year 2019. PIs will combine these highly granular mobility data with national air pollution estimates, specifically PM2.5, to calculate mobility-related exposure in major U.S. cities. This study explores a new paradigm to assessing short- and long-term individual-level exposure, serving as a reference for cross-sectional and cohort epidemiological studies.

Green TOD: Concept, Framework, and the Empirical Case Study of Austin, TX

Principal Investigator(s): Ming Zhang PhD

Green TOD is a concept derived from marrying TOD (Transit-Oriented Development) to Green Urbanism. However, Green TOD has not been widely recognized and adopted, especially in the US, mainly due to lack of operational framework and metrics for Green TOD practice and performance assessment. This project aims to 1) Clarify and substantiate Green TOD concept; 2) Develop an operational framework of and metrics for Green TOD; and 3) Test empirically Green TOD performance through Austin, TX case study.

Digital Twins as a Catalyst for Sustainable and Smart Cities

Principal Investigator(s): Junfeng Jiao PhD, Dev Niyogi PhD, Yiming Xu PhD

This project aims to develop an urban digital twin for the city of Austin that assists city planners and managers to build a sustainable and smart city. The proposed urban digital twin will incorporate a data management and visualization platform, a real-time city monitoring system, an integration of predicting models, and a dynamic urban simulation environment to achieve effective city management, better resource allocation, more efficient transportation operation, and more proactive responses to risks. This study will also build a dynamic urban simulation environment for the city of Austin, including a 3D city model, a road network model, and a traffic simulator.

Deploying Autonomous Robot Delivery System to Replace Truck Delivery and Reduce GHG Emission in Austin, TX

Principal Investigator(s): Junfeng Jiao PhD, Junmin Wang PhD

Existing robot delivery systems have been predominantly tested on small scales such as university campuses, and for specific delivery purposes. This research aims to deploy a robot delivery system in an Austin neighborhood to test the performance of ADR in terms of delivery efficiency and GHG emissions reduction, then a citywide robot delivery system deployment strategy will be developed.

Charging Forward: Crafting an Inclusive SMART Roadmap for Electric Vehicle Infrastructure in Navajo Nation, AZ

Principal Investigator(s): Junfeng Jiao PhD, Andrea Christelle PhD,

This project advocates a community-level transportation resilience anchored in equitable EV charging for the Navajo Nation. The study emphasizes fair access to EVs for marginalized groups. The research targets (1) mapping EV infrastructure in the Navajo area, (2) gauging EVCS and PH-EVCS accessibility, and (3) analyzing spatial EV infrastructure patterns for equitable allocation. Using equity analysis and machine learning, researchers create a local transport resilience blueprint for fair EVCS allocation in Navajo Nation.

Metropolitan Planning Organizations' Long-range Transportation Plans: Best Practices in Sustainability, Equity, and Climate Change

Principal Investigator(s): Tonya Sanders Thach PhD, Celeste Chavis PhD, Glenn Robinson PhD

This research seeks to compile from progressive MPOs lessons learned in implementing sustainable modes of transportation in their Long-Range Transportation plans (LRT) that account for climate change and equity in transportation. Twenty MPOs will be chosen and two authors of each of the 20 LRT plans will be interviewed for a total of 40 interviews, and content analysis will be used to develop key themes around best practices in implementing sustainable transportation, climate change and equity targets; implementation challenges; and overall lessons learned.

Determinants of Electric Vehicle and Public Charging Infrastructure Adoption in Baltimore, MD: Investigation and Policy Implications

Principal Investigator(s): Celeste Chavis PhD, Glenn Robinson PhD, Tonya Sanders Thach PhD

Past studies have noted that the most important location for EV charging is at home, followed by work, and then public locations. However, in Baltimore City, where only 14% of Baltimore’s housing stock are single family detached homes and dedicated parking is limited, home-based charging may not be an option. Thus, the objectives of this study are to understand factors such as residential location and socioeconomic characteristics that increase the likelihood of EV adoption in Baltimore City and quantify the utilization and users of public EV charging stations. The study will develop a prioritization metric for determining future public EV charging locations.

National Investigation of the Environmental, Safety and Livability Impacts of Travel Lane Width: Evidence from 10 American Cities

Principal Investigator(s): Shima Hamidi PhD, Ebrahim Azimi PhD, Reid Ewing PhD

This project is one of the most comprehensive efforts to date to address a long overdue built environmental and transportation challenge to health: unnecessarily wide travel lanes that are designed to accommodate fast and convenient driving. There has been a constant competition for space in roadways’ right-of-way. In most American cities, the automobile is the winner of this competition, making it a challenge to find space for bike lanes and sidewalks. One of the easiest and most cost-efficient way to make space for cyclists and pedestrian is to narrow travel lanes and parking lanes to an optimal width. The main drawback is safety concerns. Are wider lanes safer? A recent study in seven US Cities by the PI found that narrower lanes do not have a higher number of crashes than their wider counterparts, after controlling for 21 functional and design street characteristics. This study builds on the earlier effort by 1) expanding sample to more than 1,500 street sections with three additional cities and measuring a comprehensive set of 21 microscale street design features for these streets; 2) quantifying the impact of narrow travel lane on traffic fatalities, pedestrian safety, and bicycle safety indicators; and 3) measuring the impact of narrow lane width on pedestrian volume and activities. Finally, from the national sample of ten cities, the PIs will select one lane width reduction project for further longitudinal analysis of traffic speed, roadway capacity (traffic volume), roadway safety (crash severity and frequency) and GHG emission impacts before and after the lane width reduction.

How Actionable are Climate Action Plans? In-depth Analysis through an Integrated Policy Mix Framework

Principal Investigator(s): Ebrahim Azimi PhD, Jeff Michael PhD, Reid Ewing PhD

More than 190 local governments in the U.S have recognized the urgent need for action and have issued emergency declarations in their respected cities. However, a 2020 Brookings report shows that about two-thirds of the top 100 cities have made very little progress in implementation and are lagging their short-term emission targets, having even more challenges meeting their longer-term targets. This is mainly due to very limited knowledge and evidence on transportation-related climate mitigation policies and their impacts. Some studies highlight effectiveness of pricing policies such as New York Congestion Pricing policy which may be effective in reducing VMT and its GHG emissions but lack general support and accessibility. Other studies emphasize planning policies such as public transit improvement which likely have general acceptability but lacks financial recourses for execution particularly with recent trends of decline in transit ridership. The missing component of these studies and one key reason behind cities’ challenges on implementing climate mitigation strategies is the lack of integrated policy mixes that are complement to each other, and as a whole could offer an effective mitigation and general acceptability while addressing negative externalities such as potential equity and environmental justice challenges.

This study addresses these gaps in the literature by conducting one of the first and most comprehensive analysis on transportation-related climate mitigation policies. This study conducts 1) a systematic review of existing/implemented transportation related mitigation policies internationally, 2) the PIs will design a policy matrix with performance measures to evaluate effectiveness and externalities of mitigation policies, 3) research team will employ the policy matrix to evaluate policies obtained from Step 1, 4) PIs will review and conduct content analysis of Climate Action Plans for the top 100 major cities in the US. More specifically, researchers will derive transportation-related mitigation policies and policy mixes (if exists), 5) Research team will assess climate action plans based on the integrated policy mix framework to investigate the extent to which cities’ climate mitigation efforts correspond to the matrix performance indicators, 6) The policy analysis will be coupled with a quantitative analysis that link performance indicators in policy matrix to cities progress toward meeting GHG emission reduction targets.


A Census of the US Climate-High Risk Area Population: Transportation and Environmental Justice Considerations

Principal Investigator(s):  Shima Hamidi PhD, Ebrahim Azimi PhD

The COVID-19 pandemic has been a paradigm shift in residential preferences. Despite numerous studies on environmental, economic, transportation and public health benefits of compact development, real estate shows a preference and relocation of households from more expensive but low-climate risk areas such as Manhattan NY to relatively less expensive but high-climate-risk areas such as Phoenix, AZ and similar major cities in Florida. These trends are so alarming, particularly for sustainable transportation planning as the climate-high-risk areas are typically more sprawling and auto dependent and as a result of these trends of migration, this study hypothesizes that households are moving from transit-served areas to relatively more car-dependent places. This study seeks to investigate this gap and hypothesis in a multi-phase research design as following: 1) to identify the high-resolution location of climate-high risk areas covering three climate risk indicators (flood, fire, heat), 2) profile climate-high-risk areas socio-economic, housing, employment, transportation and the overall built environment; 3) evaluate sustainable transportation infrastructure in climate-high-risk places; 4) quantify the trends of migration to climate-high-risk areas since 2010, 5) investigate transportation, equity and environmental consequences of such migration trends.