Ensuring greener mobility is fairer mobility: a measurement of income’s effects on low-carbon transportation access in Seattle, WA by Christopher Randels
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FIGURES CHRISTOPHER RANDELS
“As Seattle continues to reduce its emissions and residents’ vehicle miles travelled (VMT), the city will need to determine which populations are bearing the primary costs of this transition.”
nthropogenic carbon dioxide (CO2) emissions are a principal cause of global warming (Schellnhuber et al. 2006). In Seattle, passenger vehicles account for over half of citywide CO2 emissions (Seattle OSE 2016), so reducing emissions in the urban mobility sector can be a key area for climate change mitigation. Emerging trends in micromobility and vehicle sharing provide new opportunities for lower-carbon transport, but not all alternate transportation modes to the single occupant vehicle (SOV) are equal in their emissions reductions, and access to these modes may not be distributed equally within cities. Inequities in transportation access can further exacerbate inequities in health and quality of life outcomes already present if higher income neighborhoods have better mobility access to goods and services (Allen & Farber 2019; Blumenberg 2017). As Seattle continues to reduce its emissions and residents’ vehicle miles travelled (VMT), the city will need to determine which populations are primarily bearing the costs of this transition. With this study, I sought to measure such cost inequities by creating hypothetical routes to various destinations and services from Seattle’s highest and lowest income neighborhoods across multiple transportation modes: walking, biking, transit, driving, bikeshare (Lime and Jump Bike), carshare (Car2Go/ShareNow), and ridehailing (Uber). By measuring the costs, emissions, and travel times for a large number of destinations across transportation modes, I sought to answer two questions. First, how different are per-person emissions for the same routes between different travel modes?
