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There is a growing body of research on trust in driving automation systems. In this paper, we seek to clarify the way trust is conceptualized, calibrated and measured taking into account issues related to specific levels of driving automation. We find that: (1) experience plays a vital role in trust calibration; (2) experience should be measured not just in terms of distance traveled, but in terms of the range of situations encountered; (3) system malfunctions and recovery from such malfunctions is a fundamental part of this experience. We summarize our findings in a framework describing the dynamics of trust calibration. We observe that methods used to quantify trust often lack objectivity, reliability, and validity, and propose a set of recommendations for researchers seeking to select suitable trust measures for their studies. In conclusion, we argue that the safe deployment of current and future automated vehicles depends on drivers developing appropriate levels of trust. Given the potentially severe consequences of miscalibrated trust, it is essential that drivers incorporate the possibility of new and unexpected driving situations in their mental models of system capabilities. It is vitally important that we develop methods that contribute to this goal.

Within a workshop on evaluation methods for automated vehicles (AVs) at the Driving Assessment 2019 symposium in Santa Fe; New Mexico, a heuristic evaluation methodology that aims at supporting the development of human–machine interfaces (HMIs) for AVs was presented. The goal of the workshop was to bring together members of the human factors community to discuss the method and to further promote the development of HMI guidelines and assessment methods for the design of HMIs of automated driving systems (ADSs). The workshop included hands-on experience of rented series production partially automated vehicles, the application of the heuristic assessment method using a checklist, and intensive discussions about possible revisions of the checklist and the method itself. The aim of the paper is to summarize the results of the workshop, which will be used to further improve the checklist method and make the process available to the scientific community. The participants all had previous experience in HMI design of driver assistance systems, as well as development and evaluation methods. They brought valuable ideas into the discussion with regard to the overall value of the tool against the background of the intended application, concrete improvements of the checklist (e.g., categorization of items; checklist items that are currently perceived as missing or redundant in the checklist), when in the design process the tool should be applied, and improvements for the usability of the checklist.

Objective: The human–machine interface (HMI) is a crucial part of every automated driving system (ADS). In the near future, it is likely that—depending on the operational design domain (ODD)—different levels of automation will be available within the same vehicle. The capabilities of a given automation level as well as the operator’s responsibilities must be communicated in an appropriate way. To date, however, there are no agreed-upon evaluation methods that can be used by human factors practitioners as well as researchers to test this. Methods: We developed an iterative test procedure that can be applied during the product development cycle of ADS. The test procedure is specifically designed to evaluate whether minimum requirements as proposed in NHTSA’s automated vehicle policy are met. Results: The proposed evaluation protocol includes (a) a method to identify relevant use cases for testing on the basis of all theoretically possible steady states and mode transitions of a given ADS; (b) an expert-based heuristic assessment to evaluate whether the HMI complies with applicable norms, standards, and best practices; and (c) an empirical evaluation of ADS HMIs using a standardized design for user studies and performance metrics. Conclusions: Each can be used as a stand-alone method or in combination to generate objective, reliable, and valid evaluations of HMIs, focusing on whether they meet minimum requirements. However, we also emphasize that other evaluation aspects such as controllability, misuse, and acceptance are not within the scope of the evaluation protocol.

In most levels of vehicle automation, drivers will not be merely occupants or passengers of automated vehicles. Especially in lower levels of automation, where the driver is still required to serve as a fallback level (SAE L3) or even as a supervisor (SAE L2), there is a need to communicate relevant system states (e.g., that the automated driving system works reliably or that there is a need for manual intervention) via the Human-Machine Interface (HMI). However, there are currently no agreed-upon guidelines that apply specifically to HMIs for automated driving. In this paper, we summarize design recommendations for visual-auditory and visual-vibrotactile HMIs derived from empirical research, applicable standards and design guidelines pertaining to in-vehicle interfaces. On this basis, we derive an initial set of principles and criteria for guiding the development and design of automated vehicle HMIs. A heuristic evaluation methodology consisting of an itemized checklist evaluation that can be used to verify that basic HMI requirements formulated in the guidelines are met is also presented. The heuristic evaluation involves an inspection of the HMI during typical use cases, judging their compliance with the proposed guidelines and documentation of identified instances of non-compliance. Taken together, the combination of the proposed guidelines and the heuristic evaluation methodology form the basis for both design and validation recommendations of automated vehicle HMIs, that can serve the industry in the important evolution of automation within vehicles.

We investigated after effects of automation in take-over scenarios in a high-end moving-base driving simulator. Drivers performed evasive manoeuvres encountering a blocked lane in highway driving. We compared the performance of drivers 1) during manual driving, 2) after automated driving with eyes on the road while performing the cognitively demanding n-back task, and 3) after automated driving with eyes off the road performing the visually demanding SuRT task. Both minimum time to collision (TTC) and minimum clearance towards the obstacle disclosed a substantial number of near miss events and are regarded as valuable surrogate safety metrics in evasive manoeuvres. TTC proved highly sensitive to the applied definition of colliding paths, and we prefer robust solutions using lane position while disregarding heading. The extended time to collision (ETTC) which takes into account acceleration was close to the more robust conventional TTC. In line with other publications, the initial steering or braking intervention was delayed after using automation compared to manual driving. This resulted in lower TTC values and stronger steering and braking actions. Using automation, effects of cognitive distraction were similar to visual distraction for the intervention time with effects on the surrogate safety metric TTC being larger with visual distraction. However the precision of the evasive manoeuvres was hardly affected with a similar clearance towards the obstacle, similar overshoots and similar excursions to the hard shoulder. Further research is needed to validate and complement the current simulator based results with human behaviour in real world driving conditions. Experiments with real vehicles can disclose possible systematic differences in behaviour, and naturalistic data can serve to validate surrogate safety measures like TTC and obstacle clearance in evasive manoeuvres., Intelligent Vehicles

Systeme zum automatisierten Fahren erlauben es, die Fahrzeugführung in einem gewissen Maß vom Fahrer an das Fahrzeug zu übertragen. Da der Fahrer auf diese Weise unterstützt, entlastet oder sogar ersetzt werden kann, werden Systeme zum automatisierten Fahren mit einem großen Potential für Verbesserungen hinsichtlich Straßenverkehrssicherheit, Fahrkomfort und Effizienz verbunden - vorausgesetzt, dass diese Systeme angemessen benutzt werden. Systeme zum hochautomatisierten Fahren stellen in diesem Zusammenhang eine besondere Herausforderung für die Mensch-Maschine-Interaktion dar: So wird es dem Fahrer bei diesem Automatisierungsgrad zwar zum ersten mal ermöglicht, das System nicht mehr permanent überwachen zu müssen und somit die Fahrtzeit potentiell für fahrfremde Tätigkeiten zu nutzen. Es wird jedoch immer noch erwartet, dass der Fahrer nach einer vorherigen angemessenen Übernahmeaufforderung die Fahrzeugführung im Bedarfsfall gewährleisten kann. Angemessenes Automatisierungsvertrauen stellt daher eine zentrale Komponente für die erfolgreiche Kooperation zwischen Fahrern und Systemen zum hochautomatisierten Fahren dar und sollte bei der Gestaltung derartiger Systeme berücksichtigt werden. Frühere Befunde weisen beispielsweise bereits darauf hin, dass unterschiedliche Informationen über automatisierte Systeme ein möglicher Ansatz sein könnten um das Automatisierungsvertrauen des Fahrers aktiv zu gestalten. Automatisierungsvertrauen als Variable in der Gestaltung von Fahrzeugtechnologie zu berücksichtigen erfordert jedoch zunächst auch in der Lage zu sein, Automatisierungsvertrauen adäquat messen zu können. In diesem Sinne war die Zielsetzung dieser Arbeit einerseits die Untersuchung verschiedener Methoden zur Messung des Automatisierungsvertrauens des Fahrers sowie andererseits die Identifikation, prototypische Umsetzung und Bewertung potentieller Ansätze zur Gestaltung von Automatisierungsvertrauen im Kontext von Systemen zum hochautomatisierten, Automated driving systems allow to transfer a certain degree of vehicle control from the driver to a vehicle. By assisting, augmenting or even supplementing the driver, automated driving systems have been associated with enormous potential for improving driving safety, comfort, and efficiency - provided that they are used appropriately. Among those systems, conditional automated driving systems are particularly challenging for human-automation interaction: While the driver is no longer required to permanently monitor conditional automated driving systems, he / she is still expected to provide fallback performance of the dynamic driving task after adequate prior notification. Therefore, facilitating appropriate automation trust is a key component for enabling successful cooperation between drivers and conditional automated driving systems. Earlier work indicates that providing drivers with proper information about conditional automated driving systems might be one promising approach to do this. Considering the role of automation trust as a variable in the design of vehicle technology, however, also requires that drivers` automation trust can be viably measured in the first place. Accordingly, the objectives of this thesis were to explore difffferent methods for measuring drivers` automation trust in the context of conditional automated driving as well as the identification, implementation and evaluation of possible approaches for designing drivers` automation trust in conditional automated driving systems. For these purposes, three driving simulator studies with N = 280 participants were conducted. The results indicate that (i) both self-report measures and behavioral measures can be used to assess drivers` automation trust in conditional automated driving systems, (ii) prior familiarization with system limitations can have a lasting effffect on drivers` automation trust in conditional automated driving systems and (iii) particularly information about the processes o

Human automation interaction is a complex process. How autonomous assistance impacts trust in automation as well as how trust affects human calibration and use of automation has been investigated for both dynamic contexts, including the internal variables (e.g., cultural characteristics) and external factors (e.g., system settings). Having standardized measures to capture trust and its antecedents is particularly critical to understanding how factors associated with the human operators and autonomous applications affects the way they are used. This paper reports the development of a trust instrument and several rounds of cross-country validation, including U.S., German, Taiwanese, and Turkish populations. The results confirm that the instrument which was developed reliably measured human trust in automation across cultures.