Are shared vehicles shared by all?

I’m happy to share a new article I wrote with Nathan McNeil that reviews the research on shared mobility and equity, “Are shared vehicles shared by all? A review of equity and vehicle sharing.” It will appear in a special issue of the Journal of Planning Literature: Transportation and Cities in the 21st Century: Will New Mobility Technologies Make Cities More Sustainable? The issue is edited by Gulsah Akar and Harvey Miller, at The Ohio State University.

We sought to understand whether shared vehicle systems – carsharing, bikesharing, and e-scooter sharing – are equitable, based on the research to date. The bottom line? No, not really, but there is potential. To answer our main question, we examine evidence in three categories.

  • Physical proximity to shared vehicles. This is a pre-requisite for accessibility. If the shared vehicles are not located nearby, not much else matters.
  • The use of vehicles by different target population groups. If some groups are underrepresented, this may indicate lower accessibility. That could be due to lack of physical proximity, but also other barriers such as physical ability, income, or lack of required technology.
  • Why and how different groups use (or not) shared vehicles. This type of evidence can reveal whether any differences in usage rates are explained by inequitable accessibility rather than differences in preferences.

We review evidence from over 120 articles and reports related to five population characteristics: income, race/ethnicity, age (older adults), gender, and disability. We also cover programs and policies to address equity, though research on the impacts of such efforts are limited.

Overall, we did not find much evidence that vehicle sharing systems are improving accessibility for disadvantaged populations, though some modeling efforts indicate the potential for doing so. Some of our findings include:

  • There are disparities in proximity to shared vehicles, particularly proximity to bikeshare for Black, Indigenous and people of color (BIPOC) and lower-income people. There are not many studies that look at proximity to carshare vehicles.
  • There are also disparities in the use of shared vehicles. Several studies find that BIPOC people use carsharing and bikesharing less, but it is sometimes unclear how much of the difference can be attributed to race vs. income.
  • Very few studies attempt to explain differences in use by these groups and only do so for bikesharing. Those studies find several barriers for BIPOC people and low-income people, ranging from lack of credit cards or information to fear of police harassment.
  • Women are less likely than men to be carshare members and even less likely to use shared bikes or e-scooters. The reasons for not using bikeshare are likely the same as why women do not bike as much as men, at least in countries with low rates of cycling. The reasons for not using carsharing are not clear.
  • The findings from limited amount of research on e-scooter sharing are mixed, but there is not strong evidence that those systems are significantly more equitable than bikesharing.
  • People with disabilities are essentially ignored in the research about vehicle sharing, and older adults are rarely considered.

Vehicle sharing offers the potential to improve mobility and accessibility for disadvantaged populations. The research we reviewed shows some efforts to help vehicle sharing achieve that potential, but there were many gaps. I’ll highlight a couple here.

First, the research that focuses on equity and vehicle sharing tends to be about bikesharing. There are likely many reasons for this, including the interests of researchers and funding agencies, availability of open data, greater public agency role in bikesharing (vs. carsharing), and greater visibility of bikesharing systems. These factors also contribute to a growing effort to make bikesharing more equitable. This is all great, but where is the effort to make carsharing more equitable? Given that many cities lack safe bicycle infrastructure and trip distances make bicycling (or e-scootering) difficult, there may be more potential for improving accessibility through carsharing. The benefits of access to a vehicle for low income people are well documented. Carsharing could provide a more economical and financially sound way of achieving those benefits, in combination with transit. There are efforts in California around expanding electric carsharing to low-income communities. Hopefully, we’ll learn from those efforts.

Second, the research is somewhat limited by the data and methods being used. Researchers have clearly taken advantage of the open data available from bikeshare systems and methods of scraping on-line data. Pair this with various GIS and Census data and you can create some cool visualizations and more regression models than anyone needs. These studies are good for assessing physical proximity. However, demographic data on users is usually minimal, so they provide limited insight on whether and how the vehicles are used by different groups. Some studies rely on user or member surveys, which provide information, but only of users. Few studies use data from both users and non-users, and rarely are those done specifically to understand vehicle sharing and equity. I understand why this is the case. Having done a study on bikeshare equity that collected survey data from users and non-users, I know that it is not easy or cheap. And, evaluating the impacts of equity programs is even more challenging than understanding access and barriers.

There is a lot more in the paper, which is available on the journal’s website. If you are at a university and have access to Sage journals, I recommend downloading that version. But, if you do not, we have made available the “author’s version” of the paper. This is a pdf of the document that was accepted for publication. This file has some typos and other small things that were fixed prior to typesetting and publication. You can download and use it for non-commercial use.

Related information

You might also want to check out another article from the same special issue by Matthew Palm and collaborators: Equity Analysis and New Mobility Technologies: Toward Meaningful Interventions. It focuses on the integration of new mobility services with transit.

And, a new blog post at TREC from recent PSU graduate Michael McQueen shares findings from his thesis using a survey of students about e-scooter use. He has some insights on the usefulness of e-scooters as first-mile/last-mile for rail transit.

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