An Evaluation of Input Controls for In-Car Interactions

The way drivers operate in-car systems is rapidly changing as traditional physical controls, such as buttons and dials, are being replaced by touchscreens and touch-sensing surfaces. This has the potential to increase driver distraction and error as controls may be harder to find and use. This paper presents an in-car, on the road driving study which examined three key types of input controls to investigate their effects: a physical dial, pressure-based input on a touch surface and touch input on a touchscreen. The physical dial and pressure-based input were also evaluated with and without haptic feedback. The study was conducted with users performing a list-based targeting task using the different controls while driving on public roads. Eye-gaze was recorded to measure distraction from the primary task of driving. The results showed that target accuracy was high across all input methods (greater than 94%). Pressure-based targeting was the slowest while directly tapping on the targets was the faster selection method. Pressure-based input also caused the largest number of glances towards to the touchscreen but the duration of each glance was shorter than directly touching the screen. Our study will enable designers to make more appropriate design choices for future in-car interactions

Nutzerorientierte Gestaltung haptischer Signale in der Lenkung: Zum Einsatz direktionaler Lenkradvibrationen in Fahrerassistenzsystemen

Die vorliegende Arbeit widmet sich dem Einsatz von Lenkradvibrationen zur Informationsübermittlung an der Schnittstelle zwischen Fahrzeug und Fahrer unter Berücksichtigung physiologischer und psychologischer Aspekte. Als besondere Eigenschaft wird die Möglichkeit zur Erzeugung örtlich aufgelöster Vibrationen erkannt. Damit ist es möglich, über einseitige Lenkradvibrationen Richtungsinformationen an Fahrer zu kommunizieren. In drei Hauptstudien werden mit insgesamt 150 Probanden verschiedene Aspekte der Fahrerreaktion auf einseitige Lenkradvibrationen untersucht. Zunächst wird in einem grundlegenden Laborexperiment die intuitive Reaktion auf einseitige Lenkradvibrationen ermittelt. Im Anschluss wird die subjektive Präferenz der einseitigen Lenkradvibration in der Anwendung als Spurverlassenswarnsignal nachgewiesen. Zuletzt wird der Versuch unternommen, die einseitige Lenkradvibration zur Initiierung einer Ausweichreaktion in einer drohenden Frontalkollisionssituation einzusetzen.In this work applications of steering wheel vibrations are discussed. Tactile excitations that are perceived with mechanosensors in the skin of the human palm are explicitly focussed to differentiate from the state of the art. Because of the compatibility of the location of stimulus and response, haptic signals at the steering wheel are advantageously utilized to influence lateral vehicle guidance. The thesis summarizes findings of the psychophysical perception of tactile steering wheel vibrations and supplements these findings with new insights on the effect of variations in specific stimulus parameters on the perceived intensity and interpretation of messages transfered by vibrations at the steering wheel. A peculiar feature of vibro-tactile stimulation is the possibility to produce spatially distributed vibrations, which allows for communication of information on direction to the driver. Based on a review of the literature, a subjective preference of lane departure warning signals relying on vibro-tactile excitation and comprising information on directionality is hypothesized. This thesis therefore focusses on single-sided steering wheel vibrations. A single-sided vibro-tactile stimulation is assumed to be semantically associated with the rumble phenomenon induced in case of lane deparuture, thus facilitating the interpretation of the warning signal and leading to an enhancement of driver reactions when utilized as a lane departure warning signal. Three main studies examining a total of 150 subjects were conducted to reveal specific aspects of driver reactions towards single-sided steering wheel vibrations. First of all, a fundamental laboratory study examined intuitive reactions on single-sided steering wheel vibrations, legitimizing the stimulus-response mapping necessary to utilize this kind of signal as a lane departure warning signal. The second study confirmed the subjective predominance of the single-sided vibration as a lane departure warning signal when comparing this signal to alternative haptic warning signals at the steering wheel that were previously optimized for this application. In a final step, the third study examined the possible application of the single-sided steering wheel vibration to initiate an evasive steering reaction in case of an imminent forward collision situation Based on the results of the experimental studies conducted in this work, the utilization of the single-sided steering wheel vibration as a lane departure warning signal is strongly recommended. The signal both transfers the reason for the warning and recommends an action in a discrete and unintrusive manner. Any further application of the single-sided vibration, particularly the advice on a steering reaction in a collision situation, which was originally favored, can not be supported based on the present work

Novel Multimodal Feedback Techniques for In-Car Mid-Air Gesture Interaction

This paper presents an investigation into the effects of different feedback modalities on mid-air gesture interaction for infotainment systems in cars. Car crashes and near-crash events are most commonly caused by driver distraction. Mid-air interaction is a way of reducing driver distraction by reducing visual demand from infotainment. Despite a range of available modalities, feedback in mid-air gesture systems is generally provided through visual displays. We conducted a simulated driving study to investigate how different types of multimodal feedback can support in-air gestures. The effects of different feedback modalities on eye gaze behaviour, and the driving and gesturing tasks are considered. We found that feedback modality influenced gesturing behaviour. However, drivers corrected falsely executed gestures more often in non-visual conditions. Our findings show that non-visual feedback can reduce visual distraction significantl