Autonomous Vehicles and the Future of Terrestrial Mobility: a Bibliometric and Integrative Review 

Mots-clés:

Résumé:

1 – Purpose
Vehicle automation and its consequent adoption by consumers is an area of expressive interest among academics and practitioners. In the near future it is expected that Autonomous Vehicles (AVs) will offer greater comfort of traveling at lower prices and, at the same time, it could increase the capacity of the roads (Wadud, 2017).
On the industry side, AVs have been gaining a great deal of attention from the media and have generated much expectation among members of society. All leading conventional car manufacturers are known to have an automated vehicle program, with some stating the availability of fully automated vehicles in showrooms by 2020 (Wadud, 2017).
All of these activities have generated an acute interest among researchers and transportation professionals about the potential impacts of vehicle automation on the transportation system. Most of the attention has been in the context of how full automation could substantially improve road safety, and change the way we travel (Wadud et al., 2016) or change how we own or share vehicles (Krueger et al., 2016), also affecting the use of energy and carbon emissions (Wadud and Anable, 2016) which would result in other broader societal impacts (Correia et al., 2016).
Regarding such considerations, the following questions emerged as guidelines for this paper: How does the terrestrial mobility and the AVs study are linked? What are the main trends of analysis? In this sense, this paper aims to identify– from a bibliometric and systematic literature review of AVs studies indexed in the Web of Science database – the main characteristics of this domain, as well as its evolution, in order to highlight potential gaps for prospective studies.

2 – Research design
The present study was conducted from November/2017 to January/2018, it is descriptive study with quantitative approach. It is characterized as a bibliometric and systematic research based on articles indexed at Thomson Reuters’ Web of Science database. The methodological approach was adapted from Gandia et. al (2017) and it was structured as follows: 1) delimitation of the scope of analysis and selection of papers; 2) descriptive analysis of papers based on Web of Science metadata; 3) in-depth analysis of papers based on CiteSpace; 4) interpretation and discussion of results. The search led to 938 papers published between 1980 to 2017.

3 – Main results
The first publication on the subject occurred in 1980 and maintained a relatively linear growth until 2009, where there was an exponential growth culminating in 131 articles in 2017. A similar pattern was also observed regarding the number of citations per year, with the most cited article "Smart Cars on Sarmet Roads - problems of control" (Varaiya, 1993) accounting for 562 citations of the total followed by the works of Enzweiler and Gavrila (2009) with 469 citations and Fiorini and Shiller (1998) with 444 citations. Results have also shown a great heterogeneity regarding authorship. As for the countries that published the most, the US stands out with 29.10% of the publications, followed by China (19.19%), that is, these two countries alone account for almost half of the publications on the subject. For the most published Journals, the "IEEE Transactions on Intelligent Transportation Systems" comes first with 13.11% of the publications, which is equivalent to 123 articles, a lot more than the second place "Sensor" with 2.77% of publications. The main research areas covered were “Engineering”, with 35% published scientific articles, “Transportation” –21% articles, and “Computer Science” with 17%.
The systematic stage pointed to a research predominance (1980-1990) that focused on the use of Intelligent Vehicle Systems for safety and security issues (Chen; Ervin, 1990, Shatteredver, 1993, Van Der Heijden; Van Harten, 2007), control (Khattak, Schofer and Koppelman, 1993) and travel costs (Lafortune, Sengupta and Kaufman et al., 1993; Malik; Baabiker, 2010). In a change of perspective, the research began to direct their efforts to understand the terrestrial mobility as a service (Enoch, 2015, Hersher 2017, Wadud, 2017), forms of accessibility (Grewal, Roggeveen and Nordfalt, 2017, Meyer, Becker, Boesch, et al., 2017) and focus on users and their behavior (Robertson, Meister, Vanlaar et al., 2017). Thus, it is possible to identify a growing research trend on studies focused on mobility provided by autonomous vehicles as services, as well as greater focus on core technologies for user behavior, safety and accessibility.

4 – Practical implications
The paradigm shift of theoretical fields becomes visible starting from Enoch (2015) studies with a vision of shared transportation services, and with Hersher (2017) studies regarding new model contracts for public transport services. Grewal, Roggeveen and Nordfalt (2017) present the impact of the autonomous vehicles in the retail, giving another character to the mobility / accessibility. Meyer, Becker, Boesch, et al. (2017) present the impact of accessibility afforded by new forms of land mobility in urban areas. Wadud (2017), presents the commercial sectors as the probable first adopters of complete automation. Finally, Robertson, Meister, Vanlaar et al. (2017), study the negligent behavior of drivers against the use of new technologies of the autonomous vehicles. Finally, Robertson, Meister, Vanlaar et al. (2017), study the negligent behavior of drivers against the use of new technologies of the autonomous vehicles.
In this way, it is possible to verify that current research trends focus on mobility as a service. In the case of vehicle sharing, in the accessibility provided by the autonomous vehicles and by the business model of the terrestrial mobility, causing alteration of distinct sectors of the economy and with a greater focus on the behavior of the users of the innovation, characteristics that are also found in the proposals of these same authors for future research.