User experience of a self-driving minibus - reflecting vision, state and development needs of automated driving in public transport

Beside sharing, electrification of drives, and on-demand operations, the idea of using automated vehicles (AV) in public transport is one building block that is often included in conceptions of a sustainable and efficient future mobility system. If successfully implemented, it could allow new public transportation services where this is not economically feasible at present. The success of such services will crucially depend on their use by the population, which is in turn determined by perceptions of their usefulness, ease of use, safety, and attractiveness. We provide insights on user perceptions of an urban self-driving minibus service in the project HEAT (Hamburg Electric Autonomous Transportation) from the second phase of pilot operation in 2021. Based on data from passenger surveys (n = 446) that were conducted directly after the ride, we analyse the status of progress and identify further development needs from a user perspective. Results show positive attitudes towards using driverless vehicles in public transport, but also a need to further improve system performance in order to create a viable mobility alternative. We point out and discuss measures how performance could be increased

DLR Workload Assessment Tool (DLR-WAT)-Official English Version

This article presents an official English translation of the "DLR - Workload Assessment Tool" (DLRWAT), an originally German language questionnaire for subjective self-assessment of workload originally published in 2018. The DLR- WAT assesses deviations from a subjective optimum of workload more explicitly than existing measurement tools such as the NASA-TLX. The rationale behind the development of this tool is found in the increasing coexistence of humans and automation technology in sociotechnical systems across application domains such as transportation. Automation technology assists and takes over tasks formerly executed by humans as actors, resulting in changing human roles ranging for example from more passive monitoring tasks to short term interventions in cases of malfunction. In general, automation can relieve humans and increase their comfort. Yet, the issue of unbalanced workload and especially more prevalent underload needs to be targeted given the changing task environments faced by staff in the transportation domain. However, instruments for the subjective assessment of workload have so far lacked clear differentiation between underload and overload anchored in relation to a subjectively optimal level of workload. The DLR-WAT was developed to fill that gap, while greatly relying on the general format of the widely established NASATLX. The tool comprises a total of eight subscales. On six of the eight subscales (information acquisition, knowledge retrieval, decision-making, motor and physical demand, temporal demand, effort), the respondent can indicate his or her state of workload in relation to the personal optimum, which is located in the middle of each subscale. The two other subscales of the DLR-WAT (frustration, performance) are designed one-dimensionally, since an optimal level of frustration is characterised by the absence of frustration and the highest possible performance equals the theoretical optimum. The consideration of the personal optimum of workload in the first six subscales is thought to enable more detailed workload analyses distinctively imaging underload and overload in the areas represented by the subscales. In designing future transportation systems, this tool enables identification of the targeted balance between overload and underload across subscales and allows informed subsequent allocation of tasks between humans and automation accordingly

User experience of an automated on-demand shuttle service in public transportation

Autonomously driving shuttles with electric drive are envisioned to play a complementary role in public transportation in the near future. These vehicles may be used in scenarios where the use of full-sized busses is not technically feasible or economically viable. The compact size of automated shuttles offers the opportunity to operate in narrow streets, to connect suburban areas and to supply on-demand first and last mile services. The integration of an on-demand shuttle service into public transportation was tested and evaluated in a real-world trial in Hamburg-Bergedorf (Germany). A survey covering a large variety of aspects of user experience was created and distributed among users. Overall, the passengers were satisfied with the on-demand shuttle service and indicated that they could imagine to use such a service in the future. The field trial provided valuable insights and revealed the development potential of on demand shuttle services in public transportation, motivating to continue research in this area

Potential of auxiliary strobe lights on train locomotives to improve level crossing safety

Inattentiveness of road users on approach to passive railway crossings represents a major threat to level crossing safety. An auxiliary strobe light system installed on trains in addition to existing headlights may help address this issue by providing an ergonomic way of attracting human attention to the level crossing and to the train. The objective of this paper was to investigate the ergonomics and safety potential of auxiliary strobe light systems. A system was implemented on a real railway vehicle and in the virtual environment of a driving simulator. Acceptance of the system, including its usefulness and perceived benefits and drawbacks, as well as its objective effectiveness, were evaluated using questionnaires, behavioural measures, and eye tracking. The safety potential of the system was evaluated with respect to fatal level crossing accidents. The auxiliary strobe lights were preferred over normal lights and were rated as useful, reducing driving speeds, increasing visual scanning at level crossings, and thus aiding detection of a train. The system has the potential to prevent 6–30% of level crossing accidents in Europe. The results suggest that it might be worthwhile to test auxiliary strobe lights in a larger scale real-world experiment. Especially on railway lines with a high number of passive level crossings, this system can be expected to increase safety by supporting timely detection by road users and preventing accidents caused by inattentiveness

Testing a digital level crossing warning system for road traffic users with a naturalistic driving study

The points where roads intersect with railroads, called level-crossings, have traditionally been considered dangerous due to the excessive severity of accidents that have occurred involving all kinds of road vehicles and trains. They are most frequently protected with regular safety systems like barriers of light signals, however numerous level-crossings still remain unprotected. In addition, the maintenance status of level crossings differs strongly across Europe. As a consequence, some level crossings pose serious safety threats to road- and rail users, if the level crossing safety infrastructure does not exist or is not properly maintained and operated. Especially at level crossings in urban areas of municipalities in developing countries in Europe, it is often overly costly or even impossible to protect a high number of level crossings and maintain them on a regular basis. Digitalization, the huge coverage of mobile telecommunications networks and the penetration of smart phones and mobile devices in society offer a starting point for alternative, hi tech safety measures, that promise to be cheap as well as effective. Such a system has been developed and tested in Thessaloniki, where a mobile device elicits an auditory as well as a visual warning whenever the user drives in close proximity and heading to any of the 30 level crossings located in the suburbs of the city. Some trains have also been equipped with Global Navigation Satellite System (GNSS) sensors which record and transmit highly accurate spatiotemporal data, so when they approach the level crossings the mobile users also receive the estimated time of arrival on their smart phones and tablets. Three taxis were equipped with a naturalistic driving platform, consisting of cameras and a GPS sensor, to track the behavior of the drivers whenever they approached level crossings. The equipment was installed taking into consideration both the safety of all passengers and the privacy of customers. Only the drivers and surroundings of the vehicles were recorded, for a prolonged period that lasted more than two months and resulted in more than 1TB of relevant video data for further analysis. During the first month the alert system was not activated, in order to collect baseline data. The safety relevant behavior of the drivers in the context of level crossings before the implementation of the assistance system was compared to their behavior when using the system

Safer Level Crossings by improved Road-Rail Infrastructure Design

The European project SAFER-LC – Safer level crossing by integrating and optimizing road-rail infrastructure management and design – aims to improve safety in road and rail transport by minimising the risk of LC accidents, focusing on both technical solutions and human processes. The presentation introdcued some exemplary solutions developed in the project and the results obtained in the pilot tests, with a focus on a human-factors perspective on LC safety. An overview of other project activities was also given. All results are collected in the SAFER-LC toolbox (http://toolbox.safer-lc.eu/), which will be accessible from the end of the project on

SAFER-LC: Innovative Lösungen für mehr Sicherheit am Bahnübergang

Im hochsicheren System "Bahn" stellen Kreuzungen mit dem Straßenverkehr nach wie vor Punkte mit erhöhtem Risiko dar. Das europäische Projekt SAFER-LC zielt auf die Identifikation von Unfallursachen und die Ableitung von Maßnahmen zur Erhöhung der Sicherheit an Bahnübergängen ab. Dabei werden das physische Erscheinungsbild von Übergängen, existierende Systeme von Signalen und Barrieren und die technischen Möglichkeiten der Digitalisierung und Vernetzung ebenso unter die Lupe genommen wie die Strukturen und Prozesse, in welche die Abwicklung des Schienen- und Straßenverkehrs eingebettet ist

Bedarfsgerecht und selbstfahrend – Welche Anforderungen haben Nutzer an ÖPNV mit autonomen Fahrzeugen?

Überblick über Methoden und ausgewählte Ergebnisse der nutzerzentrierten Forschung mit Blick auf den Einsatz fahrerloser Fahrzeuge im ÖPNV

User-needs-based design of public transport with autonomous vehicles: User-centered research in the project HEAT

The use of autonomous vehicles for public transportation is currently being tested in pilot operations around the world. The talk gives an overview of the user-centered research activities in the project HEAT (Hamburg Electric Autonomous Transportation) in which an autonomous shuttle service was developed and tested in three iteration steps in the Hamburg district of HafenCity (Germany)

Behaviorally effective design for in-car fatigue warnings

Müdigkeitswarnsysteme (MWS) sind eine relativ neue Form der Fahrerassistenz, in deren Entwicklung der Forschungsschwerpunkt bisher deutlich auf der Detektionsseite lag. Wenig ist darüber bekannt, wie wirksam diese Systeme tatsächlich das Risiko müdigkeitsbedingter Unfälle mindern und welche Faktoren der Warnungsgestaltung für die angestrebte Sicherheitswirkung ausschlaggebend sind. Mit Blick auf den problematischen Fahrerzustand kann grundsätzlich nur eine Reduktion der Müdigkeit das Sicherheitsrisiko effektiv verringern. Ziel einer Warnung ist daher, den Fahrer zu einer Pause zu bewegen, in der er Koffein zu sich nehmen und / oder einen Kurzschlaf halten sollte. Allerdings wirken auf Ebene der Überzeugungen, Einstellungen und Motivation des Fahrers eine Reihe psychologischer Prozesse diesem Zielverhalten entgegen. Zwei besondere Herausforderungen für die Warnungswirkung sind die Tendenz zu unrealistischem Optimismus in der Einschätzung des persönlichen Risikos und die Tendenz zur Vermeidung unmittelbarer subjektiver Handlungskosten der Pause. Vor diesem theoretischen Hintergrund wurde die Wirkung verschiedener Warnungsvarianten auf Kognitionen, Motivation und Verhalten untersucht. Zu diesem Zweck wurde ein neues experimentelles Paradigma entwickelt, mit Hilfe dessen im Fahrsimulator die Anreizsituation einer realen Warnungssituation nachgestellt werden kann. Zunächst wurde durch teilweise Schlafdeprivation und die Ausnutzung circadianer Leistungstiefs ein hohes Grundniveau von Müdigkeit bei den Teilnehmern erzeugt. Ergänzend wurde eine Konstellation aus möglichen finanziellen Gewinnen und Verlusten geschaffen, die die grundlegenden Elemente der Motivationslage des Fahrers in einer realen Warnungssituation nachbildet. Während simulierter Fahrten auf einer monotonen Strecke wurde der Fahrerzustand überwacht. Bei Erreichung des definierten Müdigkeitskriteriums erhielten die Fahrer eine von mehreren möglichen Rückmeldungen. In Experiment 1 wurden zwei Warnungsvarianten verglichen: eine Standardwarnung (Kaffeetassensymbol) und eine Warnung mit einem Bild des Fahrers aus der aktuellen Situation, die mit Fokus auf eine hohe Überzeugungswirkung neu entwickelt wurde. Auf der Ebene verhaltensrelevanter Überzeugungen wies die Gruppe der mit eigenem Bild gewarnten Fahrer hierbei höhere Ausprägungen hinsichtlich der Gefährdungswahrnehmung und hinsichtlich der wahrgenommenen Effektivität einer Pause auf. Die Inzidenz von Pausen war jedoch insgesamt sehr gering. In Experiment 2 wurden die Anreizbedingungen verschärft und die Wirkung beider Warnungsvarianten mit einer Situation ohne Warnsystem verglichen. Hierbei zeigte sich, dass die Standardwarnung die Gefährdungswahrnehmung und Pausenwahrscheinlichkeit zwar in erwarteter Richtung, aber nur in sehr geringem Umfang beeinflusste. Die Warnung mit eigenem Bild führte konsistent zu größeren Effekten in verhaltensrelevanten Überzeugungen und beobachteten Pausen. In beiden Experimenten wurde zudem der situative Kontext der Warnung variiert, indem die Warnung entweder relativ nah dem Ziel oder in höherer Zielentfernung gegeben wurde. Erwartungsgemäß wirkte sich eine größere Nähe zum Ziel erschwerend auf Pausenmotivation und –verhalten aus. Die Ergebnisse geben erste Anhaltspunkte darauf, wie durch eine stärkere Berücksichtigung der Überzeugungs- und Motivationsfunktion in der Warnungsgestaltung die Sicherheitswirksamkeit von Müdigkeitswarnsystemen erhöht werden kann. Neben der Entwicklung von Detektionssystemen sollte sich empirische Forschung in Zukunft verstärkt auf die messbaren Sicherheitseffekte von Warnungen sowie die vermittelnden psychologischen Mechanismen richten, damit auch die bisher wenig berücksichtigte Outputseite von Müdigkeitswarnern optimiert werden kann.Drowsiness warning systems are a relatively new kind of driver assistance. In their development so far, there was an articulate research focus on the problem of drowsiness detection. Little is known about how effective these systems actually are in reducing the risk of drowsiness-related accidents and about what aspects of warning design are crucial in achieving the desired effect on safety. As to the critical driver state, only a reduction in drowsiness can effectively mitigate the safety risk. Therefore the objective of a warning is to convince the driver to take a break during which he should ingest caffeine and / or take a short nap. However, on the level of beliefs, attitudes and motivation, a number of psychological processes counteract this desired behavior. There are two tendencies that represent a particular challenge to warning effectiveness: the optimism bias in the appraisal of personal risk and the tendency to avoid immediate subjective response costs associated with a break. Against this background, the current studies examined the effect of different warning alternatives on cognitive, motivational and behavioral variables. For this purpose, a new experimental paradigm was developed for reproducing, in the driving simulator, the constellation of incentives typical of a real warning situation. A high initial level of drowsiness was induced among participants by partial sleep deprivation and by exploitation of circadian lows in performance. In addition, a constellation of potential gains and losses was created to emulate the most important elements of driver motivation in a real warning situation. Driver state was monitored during simulated drives on a monotonous road. At meeting a defined drowsiness criterion, drivers were given one of several feedback variants. Experiment 1 compared two warning alternatives: a standard warning (coffee cup symbol) and a warning involving an image of the driver derived from the current situation, which was newly developed with focus on high persuasiveness. On the level of behaviorally relevant beliefs, the group of drivers warned by means of their own image scored higher on subjective vulnerability as well as perceived effectiveness of a break. Overall, the incidence of breaks was extremely low however. In Experiment 2, the incentive conditions were exacerbated, and the effects of either warning alternative were compared to a situation without any warning system. It turned out that the standard warning affected subjective vulnerability and break frequency in the expected direction, but only to a very small extent. The warning involving the driver image consistently entailed larger effects on behaviorally relevant beliefs and observable breaks. Moreover, in both experiments, the situational context of the warning was varied by displaying it either in close proximity to the destination or at a larger distance to go. As expected, close proximity to one’s destination had adverse effects on motivation to take a break and observable breaks. The results provide initial evidence as to how the safety effect of drowsiness warning systems can be enhanced by greater consideration of the persuasive and motivational functions in warning design. Alongside the development of detection technology, future empirical research should be directed to a greater extent at the measurable effectiveness of warnings and the mediating psychological processes in order to optimize not only the input, but also the output of drowsiness warning systems