Transportation Impacts of Affordable Housing in the USA
Introduction
Transportation Impacts of Affordable Housing: A Pathway to Equitable Development
The intersection of affordable housing and transportation planning is a critical yet often overlooked aspect of urban development. As cities grapple with rising housing costs and the need for sustainable transportation solutions, understanding how affordable housing influences travel behavior is essential. Traditional methods of assessing transportation impacts, such as those outlined by the Institute of Transportation Engineers (ITE), often fail to account for the unique travel patterns of low-income residents. This oversight can lead to overestimations of vehicle use, resulting in unnecessary costs for affordable housing projects and misaligned urban planning strategies. This paper explores the relationship between affordable housing, urban context, and travel behaviour, offering insights into how development policies can better reflect the realities of low-income households.
The Challenge of Affordable Housing and Transportation
Affordable housing is a pressing issue in many urban areas, with a growing number of households struggling to find rental units within their budget. Between 2005 and 2015, the share of households renting in the U.S. increased from 31% to 37%, while incomes stagnated at 1995 levels (Joint Center for Housing Studies, 2015). This mismatch between housing supply and demand is exacerbated by the high costs of constructing affordable housing, particularly in location-efficient areas—those with good access to public transit, jobs, and services. Low-income households, often unable to afford personal vehicles, rely heavily on public transit, walking, and cycling. However, the development of affordable housing in these areas is increasingly expensive due to regulatory and financial barriers, such as zoning restrictions and insufficient government subsidies.
The Role of Transportation Impact Analysis
Transportation impact analysis is a standard part of the development review process, aimed at assessing the additional demand new developments place on transportation systems. However, the methodologies used, such as those in the ITE Trip Generation Handbook, often fail to differentiate between the travel behaviors of residents in affordable housing and those in market-rate housing. This lack of differentiation can lead to overestimations of vehicle trips, resulting in higher impact fees and unnecessary infrastructure investments. For example, low-income households are less likely to own cars and more likely to use public transit or walk, yet these patterns are rarely reflected in transportation impact assessments.
Study Methodology and Findings
This study uses data from the 2010-2012 California Household Travel Survey to examine how income, urban context, and housing type influence travel behaviour. The analysis focuses on two key metrics: home-based vehicle trips and home-based personal trips. The results reveal significant differences in travel behaviour based on income and urban context. Lower-income households generate fewer vehicle trips, particularly in urban areas with good access to public transit and mixed-use developments. For instance, households in urban cores make 41% of their trips by automobile, compared to 92% in non-urban areas. This suggests that affordable housing located in urban areas can significantly reduce vehicle dependency, aligning with broader sustainability goals.
The study also highlights the importance of considering regional variations in travel behaviour. For example, households in Los Angeles County generate more vehicle trips than those in other parts of California, even when controlling for urban context. This underscores the need for localized data in transportation impact assessments, as national averages may not accurately reflect regional travel patterns.
Implications for Affordable Housing Development
The findings have important implications for affordable housing policy and development. Traditional transportation impact assessments, which rely on vehicle trip estimates from ITE, often overestimate the transportation impacts of affordable housing. This can lead to higher development costs, as impact fees are based on these inflated estimates. For example, a 50-unit affordable housing development in Pasadena could be overcharged by nearly $60,000 in transportation impact fees if the assessment fails to account for the lower vehicle use of low-income residents.
To address this issue, the study recommends adopting more nuanced transportation impact assessment methods that consider income, urban context, and housing type. This could involve using person trip data, which is less sensitive to urban context than vehicle trip data, as a starting point for assessing transportation impacts. Additionally, cities could offer reduced parking requirements for affordable housing developments, as low-income households are less likely to own cars and more likely to use alternative modes of transportation.
Conclusion
The integration of affordable housing and transportation planning is essential for creating equitable and sustainable urban environments. By understanding the unique travel behaviours of low-income households, cities can develop more accurate transportation impact assessments and reduce unnecessary costs for affordable housing projects. This study highlights the need for localized data and context-sensitive methodologies in transportation planning, offering a pathway to more equitable development policies. As cities continue to grow and evolve, it is crucial that affordable housing and transportation planning work hand in hand to create inclusive, accessible communities for all residents.
For further reading:
Transportation impacts of affordable housing: Informing … – JSTOR
Improving transportation impact analyses for subsidized …