The Impact of an Adaptive User Interface on Reducing Driver Distraction Patrick Tchankue NMMU-Summerstrand Campus (South) University Way, Summerstrand 6001 Port Elizabeth, South Africa +27 41 5042094 Patrick.TchankueSielinou@nmmu. ac.za Janet Wesson NMMU-Summerstrand Campus (South) University Way, Summerstrand 6001 Port Elizabeth, South Africa +27 41 5042323 Janet.Wesson@nmmu.ac.za Dieter Vogts NMMU-Summerstrand Campus (South) University Way, Summerstrand 6001 Port Elizabeth, South Africa +27 41 5042089 Dieter.Vogts@nmmu.ac.za ABSTRACT This paper discusses the impact of an adaptive prototype in-car communication system (ICCS), called MIMI (Multimodal Interface for Mobile Info-communication), on driver distraction. Existing ICCSs attempt to minimise the visual and manual distraction, but more research needs to be done to reduce cognitive distraction. MIMI was designed to address usability and safety issues with existing ICCSs. Few ICCSs available today consider the driver’s context in the design of the user interface. An adaptive user interface (AUI) was designed and integrated into a conventional dialogue system in order to prevent the driver from receiving calls and sending text messages under high distraction conditions. The current distraction level is detected by a neural network using the driving speed and steering wheel angle of the car as inputs. An adaptive version of MIMI was compared to a non-adaptive version in a user study conducted using a simple driving simulator. The results obtained showed that the adaptive version provided several usability and safety benefits, including reducing the cognitive load, and that the users preferred the adaptive version. Categories and Subject Descriptors H.5.2 [Information Systems]: Information interfaces and presentation – user interfaces, evaluation/methodology. General Terms Measurement, Performance, Design, Experimentation, Human Factors. Keywords Adaptive user interface, driver distraction, in-car communication systems, neural networks, workload manager. 1. INTRODUCTION In-car communication systems (ICCSs) form a part of embedded systems, called in-vehicle information (or infotainment) systems. In-vehicle information systems provide secondary services in parallel with driving, which is the primary task. Drivers and passengers often listen to music, use maps or navigation devices and use their phones to make and receive calls and send text messages. ICCSs deal only with communication services, such as making calls and sending text messages. Today, ICCSs are becoming a common feature in many cars. Driver distraction may occur when the driver is engaged in secondary tasks such as texting or calling whilst driving. The legislation of several countries forbids the use of a mobile phone whilst driving. However, the use of hands-free systems, such as ICCSs, is legal [3]. Spoken Dialogue Systems (SDSs) are often used to facilitate the interaction with ubiquitous applications, especially in a car. These systems are sometimes criticised in terms of the high rate of speech recognition errors due to ambient noise and privacy issues. This can lead to an increase in the driver workload. ICCSs using multimodal interfaces (e.g. speech and steering wheel buttons) have attempted to address this issue by preventing or recovering from recognition errors as one modality can compensate for errors from another modality. Current ICCSs do not take into account difficult driving situations such as changing lanes, overtaking or taking a corner. Adaptive interfaces, which adapt according to the current driving situation, can be useful to minimise the driver distraction [6]. The aim of this paper is to discuss the design and evaluation of an adaptive user interface for an ICCS, called MIMI [18]. The paper proposes a model to infer difficult driving situations, which can be used as a guideline to design safer ICCSs. MIMI supports speech and steering wheel input to make calls and send text messages, using speech output. The aim of this paper is to investigate the impact of the adaptive interface on reducing driver distraction when using an ICCS. A user study was conducted to compare a non-adaptive version of MIMI to an adaptive version. This paper is structured as follows: related work is discussed in Section 2, which includes ICCS, driver distraction and adaptive interfaces. Section 3 reviews the architecture and design of MIMI. Section 4 discusses the design of the user study that was used to compare the adaptive version of MIMI to the non-adaptive version. The results of the user study are presented in Section 5 and a discussion of these results is contained in Section 6. 2. RELATED WORK The design of an interface for an ICCS was based on work done in several research areas. The following sections discuss ICCS, driver distraction and adaptive interfaces. 2.1 In-Car Communication Systems ICCSs are software systems developed to handle all communication-related tasks in vehicles. They are included in broader in-car software systems called in-car infotainment systems. Infotainment systems often include the following sub- systems [17]:  Navigation system: Provide directions and points of interest on a map. Free-standing navigation systems Copyright held by author(s) AutomotiveUI’11, November 29–December 2, 2011, Salzburg, Austria.