Automated drivability: Toward an assessment of the spatial deployment of level 4 automated vehicles

Two scenarios have shaped the discussion on the deployment of automated vehicles (AVs). The first is the revolutionary or disruptive scenario, in which a competitor would reach fully automated vehicles (level 5) in one giant leap. The second scenario renders the deployment of AVs as a lengthy process of evolutionary vehicle automation, progressing from specialized, controlled and restricted conditions, i.e. operational design domains (ODDs), to ever more complex ones. But as it becomes more and more clear that there are large uncertainties about how far in the future level 5 AVs become available, in the near future situations in which the driver is replaced completely, i.e. not requiring driver interventions, only seem feasible in specific ODDs and cities will likely be faced by highly automated vehicles (level 4) equipped with automated driving systems (ADSs) for specific ODDs over a longer period. However, cities comprise different street spaces with various conditions which lead to different requirements for the ADSs and could affect the deployment of level 4 AVs and thus the impacts of AVs in cities in the near future. This paper presents a framework and related indicators for assessing the automated drivability, i.e. the suitability of street spaces for the functioning operation of ADSs from a technical-infrastructural point of view, based on the relationship between the current technological development state of ADSs and different (urban) street spaces. Using the case study of the city of Vienna in Austria to apply the framework, a set of indicators for the different components of the framework is calculated and integrated to build an automated drivability index (ADX), illustrating the automated drivability within the street network. The results are a first step to indicate which areas are more suitable for level 4 AVs from a technological point of view, as well as areas where a deployment of AVs would only be possible after larger adjustments of the infrastructure or at considerably lower than intended speeds; thus, detailing the complexity of driving urban street spaces in a yet unprecedented level. Besides other aspects this can give hints for policy makers and other stakeholders where to facilitate the deployment of AVs.