Investigation of the influences of sensors for automated driving on the perception of exterior design
Authors: Fischer Lutz , Gadermann Lars , Holder Daniel , Ihle Niklas , Schlecht Julius , Maier Thomas 
Published: June 2023

Automated driving requires a large number of sensors. They are used to detect environmental influences and regulate vehicle guidance. Many of these sensors have to fulfil requirements regarding position and functional installation space. This creates a conflict of objectives between aesthetically appealing integration into the design and functional integration into trim parts or an aerodynamic concept. In addition, the perception of the sensors by vehicle users and other road users could favour the recognition of an automated vehicle (AV). Numerous studies showed the fundamental importance of a vehicle's exterior, especially with regard to the various semantic aspects of the resulting product effect. This is particularly apparent with regard to the communication between the driver or AV and other road users. Therefore, in this paper we consider the preconditioning of the user in relation to the degree of integration of sensor technology for automated driving. For this purpose, sensor configurations differing in shape and colour are applied to a concept car and examined in an eye-tracking study with regard to their influence on the perception of passengers and other road users. This will provide designers and engineers with insights into the design of sensor clusters in the exterior design of future vehicles.METHODSIn a first step, existing studies were systematically examined to determine the influence of the exterior design on the perception of the vehicle. In addition to the basic idea of appeal, the preconditioning by the design was examined in particular. It has been shown that the exterior design has an influence on the user's driving style, the spatial perception and the brand affiliation recognition. In more recent studies, the influence of so-called external HMIs (eHMI) on the perception of an automated vehicle has been increasingly investigated. Studies on the influence of more or less exposed sensors for automated driving on the perception of users or pedestrians are not known.In a second step, an eye-tracking study was therefore designed. In the study, the test persons were sequentially shown renderings in ¾ front and ¾ rear perspective of a concept car with different sensor configurations on the screen. The relevant sensor configurations are based on a previous study in which we conducted a position analysis and derived integration strategies for sensors. The stimulus patterns differ specifically in the sub-forms of structure (position), shape and colour. The test persons evaluated each of the stimulus patterns by means of a questionnaire with regard to their subjective impression in the use cases "crossing the street as a pedestrian" and "getting into the vehicle and being driven home". System trust, the perception of safety, recognisability and the judgement of appeal were assessed. Absolute dwell time, relative dwell time and fixation were recorded via eye tracking.RESULTSThe statistical evaluation of the results has shown that the sensors already have an influence on system trust and the perception of safety of the users and other road users in both use cases considered. In particular, for the configuration without visible sensors and additively integrated sensors, significant differences emerged as expected. As expected, there was a high degree of dispersion in the opinion towards liking the design of the users. Areas of interest were derived from the eye-tracking data via heat maps. The more accurate understanding of the perception of the degree of integration of sensors into the exterior design can support the work of designers by giving them the freedom to realise significantly more innovative designs in their design proposals compared to previous vehicles.OUTLOOKExtending the investigations to much larger vehicles, especially trucks or robotic vehicles according to SAE Level 5 without passengers could show whether the perception of sensors can already be used as a salient feature in exterior design. Furthermore, it should be investigated whether there are interactions with eHMI on AVs. In addition, system trust and safety perception could be investigated in an extended virtual reality test design with a variety of other relevant use cases such as: "oncoming AV at right-before-left intersection" to show influences of immersion. Also, the influence of time and the associated habituation factor certainly plays a role. For this reason, the effects of road users getting used to the sight with sensors should also be considered.ACKNOWLEDGMENTSThis research was supported by Federal Ministry for Economic Affairs and Climate Action in the national research project RUMBA.