Autonomous Mobility

Autonomous vehicles (AVs) represent potentially disruptive and innovative changes to public transportation (PT) systems. However, the exact interplay between AV and PT is understudied in existing research. This paper proposes a systematic approach to the design, simulation, and evaluation of integrated autonomous vehicle and public transportation (AV + PT) systems. Two features distinguish this research from the state of the art in the literature: the first is the transit-oriented AV operation with the purpose of supporting existing PT modes; the second is the explicit modeling of the interaction between demand and supply.

We highlight the transit-orientation by identifying the synergistic opportunities between AV and PT, which makes AVs more acceptable to all the stakeholders and respects the social-purpose considerations such as maintaining service availability and ensuring equity. Specifically, AV is designed to serve first-mile connections to rail stations and provide efficient shared mobility in low-density suburban areas. The interaction between demand and supply is modeled using a set of system dynamics equations and solved as a fixed-point problem through an iterative simulation procedure. We develop an agent-based simulation platform of service and a discrete choice model of demand as two subproblems. Using a feedback loop between supply and demand, we capture the interaction between the decisions of the service operator and those of the travelers and model the choices of both parties. Considering uncertainties in demand prediction and stochasticity in simulation, we also evaluate the robustness of our fixed-point solution and demonstrate the convergence of the proposed method empirically.

We test our approach in a major European city, simulating scenarios with various fleet sizes, vehicle capacities, fare schemes, and hailing strategies such as in-advance requests. Scenarios are evaluated from the perspectives of passengers, AV operators, PT operators, and urban mobility system. Results show the trade off between the level of service and the operational cost, providing insight for fleet sizing to reach the optimal balance. Our simulated experiments show that encouraging ride-sharing, allowing in-advance requests, and combining fare with transit help enable service integration and encourage sustainable travel. Both the transit-oriented AV operation and the demand-supply interaction are essential components for defining and assessing the roles of the AV technology in our future transportation systems, especially those with ample and robust transit networks.

https://doi.org/10.1016/j.trc.2018.10.018

Autonomous vehicles (AVs) are envisioned to reduce road fatalities by switching control of safety-critical tasks from humans to machines. Realizing safety benefits on the ground depends on technological advancement as well as the scale and rate of AV adoption, which are influenced by public perceptions. Employing multilevel structural equation modeling, this paper explores differences in perceptions of AV safety across 33,958 individuals in 51 countries. At the individual level, young males report higher perceptions of current AV safety and predict fewer years until AVs are safe enough for them to use. Since young males are more likely to undertake risky driving behavior, their positivity towards AV safety could lead to more rapid manifestations of safety benefits. Urban, fully employed individuals with higher incomes and education levels also report fewer years until AVs are safe to use. The multilevel model identifies country-level effects after controlling for individual characteristics. Developed countries with greater motorization rates and lower road death rates tend to have greater awareness of AVs but are more pessimistic about their present and future safety. Individuals in developing countries that face greater road safety challenges, particularly involving 2- and 3-wheeled vehicles, predict fewer years until AVs will be safe enough for them to use. Higher AV safety perception among the most risk-taking road users and in developing countries coincide with sociodemographic groups and geographic areas facing the greatest road safety challenges and most in need of improvement, highlighting a potential opportunity to reduce the global disparity in road safety.

https://doi.org/10.1016/j.ssci.2019.07.022

This paper proposes and simulates an integrated autonomous vehicle (AV) and public transportation (PT) system. After discussing the attributes of and the interaction among the prospective stakeholders in the system, we identify opportunities for synergy between AVs and the PT system based on Singapore’s organizational structure and demand characteristics. Envisioning an integrated system in the context of the first-mile problem during morning peak hours, we propose to preserve high demand bus routes while repurposing low-demand bus routes and using shared AVs as an alternative. An agent-based supply-side simulation is built to assess the performance of the proposed service in fifty-two scenarios with different fleet sizes and ridesharing preferences. Under a set of assumptions on AV operation costs and dispatching algorithms, the results show that the integrated system has the potential of enhancing service quality, occupying fewer road resources, being financially sustainable, and utilizing bus services more efficiently.

https://doi.org/10.1016/j.tra.2018.04.004

Problem, research strategy, and findings: Local government policies could affect how autonomous vehicle (AV) technology is deployed. In this study we examine how municipalities are planning for AVs, identify local characteristics that are associated with preparation, and describe what effects bureaucrats expect from the vehicles. We review existing plans of the 25 largest U.S. cities and survey transportation and planning officials from 120 cities, representative of all municipalities with populations larger than 100,000. First, we find that few local governments have begun planning for AVs. Second, cities with larger populations and higher population growth are more likely to be prepared. Third, although local officials are optimistic about the technology and its potential to increase safety while reducing congestion, costs, and pollution, more than a third of respondents worried about AVs increasing vehicle miles traveled and sprawl while reducing transit ridership and local revenues. Those concerns are associated with greater willingness to implement AV regulations, but there is variation among responses depending on political ideology, per capita government expenditures, and population density. Takeaway for practice: Municipal governments’ future approaches to AV preparation will likely depend on the characteristics of city residents and local resources. Planners can maximize policy advancement if they work with officials in other cities to develop best practices and articulate strategies that overlap with existing priorities, such as reducing pollution and single-occupancy commuting.

https://hdl.handle.net/1721.1/127261

Local governments play an important role in structuring urban transportation through street design, zoning, and shared jurisdiction over ride-hailing, transit, and road pricing. While cities can harness these powers to steer planning outcomes, there is little research about what local officials think about regulatory changes related to autonomous vehicles (AV). We compile key AV-related policies recommended by scholars but rarely implemented, and conduct a survey of municipal officials throughout the United States, exploring their personal support and perceptions of bureaucratic capacity, legal limits, and political backing for each policy. This paper finds broad personal support for regulations related to right-of-way, equity, and land use, such as for increasing pedestrian space, expanding access for low-income people, and reducing sprawl. However, officials emphasized uncertain bureaucratic and legal capacity for city intervention outside of these areas, reaffirming limited local power in the federal system. Only a minority expected political support for any policy. Greater population size and more liberal resident political ideologies are strongly associated with personal and political support for many policies. Local population growth is correlated with greater capacity to undertake policies. This work contributes to the growing literature on transportation governance in the context of technological uncertainty.

https://hdl.handle.net/1721.1/131318

Studies suggest autonomous vehicles can enable a more equitable, efficient, and sustainable transportation network. Yet, experts point out this outcome is not guaranteed, and that without outside policy intervention autonomous vehicle (AV) use might actually exacerbate congestion, sprawl, and inequitable access to travel. These challenges will be most acutely felt in areas under the purview of local governments-such as transportation congestion, land use, and impacts on public transit. As such, the goal of this thesis is to assist municipal policymakers with mitigating these impacts by answering the question: How can local governments effectively regulate autonomous vehicles? Looking at Toronto, Canada, specifically, this thesis addresses the following issues: - When is a contract, and when is a regulation, the most appropriate tool to encourage AV companies to act in ways that help foster a sustainable and equitable transportation network? - What does the City of Toronto require to develop effective AV regulation? - How can the City of Toronto codify broad AV policies into specific, enforceable regulations? This thesis employs three research methods: a literature review, a document analysis, and qualitative interviews with relevant experts. The primary literature review looks at the possible benefits and harms that might come from AV development and the policies local governments can enact to correct for these externalities. Interviews were conducted with 23 experts from the public and private sectors and academia, with responses analysed and themes drawn out to develop answers to the above research questions. Finally, analysis of Toronto's Official Plan and Municipal Code helped inform the creation of a proposed Article 10-A of the code to regulate AV rideshare companies. Chapters three to five of this thesis develop a framework (laid out in Figure 0.1) for thinking about how best to design effective AV regulation. Firstly, the government needs legal capacity to regulate in a given area. Toronto, for example, is responsible for overseeing local rideshare company activity. The remaining four elements all relate to human resources. Interviews show Toronto's bureaucrats believe they have a responsibility and ability to craft effective and ambitious regulations that advance the city's goals. These willing civil servants need the time and the expertise to design good policy, and the Toronto government has an AV working group that provides a forum for such a discussion. To see regulations enacted effectively, however, the mayor and council must not only support rules eventually proposed by the working group; they may also need to approach the provincial government to convince them to craft their own complementary AV legislation. Figure 0.1. The five elements to effective regulation [illustration] Chapter six explores how broad AV policy can be applied concretely. Along with Article 10-A (Appendix C), it offers an example of the specific legal language for AV regulation. Divided into two broad categories--'Equity' and 'Urban Form and Street Space'-the article addresses some of the anticipated issues that might arise with AV rideshare operations including a need to allow citizens without a smartphone are able to use the service, limit AV rideshare travel on local roads, and ensure all neighbourhoods enjoy a relatively similar level of service (accounting for geography and density). Beyond the proposed article itself, chapter six provides feedback from Toronto officials as to the challenges the provisions in the article might face were the government to attempt their ratification. Positively, none of the regulations were unanimously viewed as infeasible, with staff seemingly eager to act boldly when it comes to addressing the challenges of AV activity. As such, this thesis can be used both by Toronto policymakers and their counterparts elsewhere as the basis for discussion in designing the specific rules for AV operations that will be incorporated into a future version of the Municipal Code.

http://dspace.mit.edu/handle/1721.1/7582