Carl Pickering

A usability evaluation toolkit for In-Vehicle Information Systems (IVISs).

Usability must be defined specifically for the context of use of the particular system under investigation. This specific context of use should also be used to guide the definition of specific usability criteria and the selection of appropriate evaluation methods. There are four principles which can guide the selection of evaluation methods, relating to the information required in the evaluation, the stage at which to apply methods, the resources required and the people involved in the evaluation. This paper presents a framework for the evaluation of usability in the context of In-Vehicle Information Systems (IVISs). This framework guides designers through defining usability criteria for an evaluation, selecting appropriate evaluation methods and applying those methods. These stages form an iterative process of design-evaluation-redesign with the overall aim of improving the usability of IVISs and enhancing the driving experience, without compromising the safety of the driver.

To twist or poke? A method for identifying usability issues with the rotary controller and touch screen for control of in-vehicle information systems

In-vehicle information systems (IVIS) can be controlled by the user via direct or indirect input devices. In order to develop the next generation of usable IVIS, designers need to be able to evaluate and understand the usability issues associated with these two input types. The aim of this study was to investigate the effectiveness of a set of empirical usability evaluation methods for identifying important usability issues and distinguishing between the IVIS input devices. A number of usability issues were identified and their causal factors have been explored. These were related to the input type, the structure of the menu/tasks and hardware issues. In particular, the translation between inputs and on-screen actions and a lack of visual feedback for menu navigation resulted in lower levels of usability for the indirect device. This information will be useful in informing the design of new IVIS, with improved usability. Statement of Relevance: This paper examines the use of empirical methods for distinguishing between direct and indirect IVIS input devices and identifying usability issues. Results have shown that the characteristics of indirect input devices produce more serious usability issues, compared with direct devices and can have a negative effect on the driver–vehicle interaction.

In-Vehicle Information Systems to Meet the Needs of Drivers

In-Vehicle Information Systems (IVISs) integrate most of the secondary functions available within vehicles. These secondary functions are aimed at enhancing the driving experience. To successfully design and evaluate the performance of these systems, a thorough understanding of the task, user, and system is required. This article presents a review of these three variables in the context of IVISs, which aims to enhance understanding of this specific task–user–system interaction. A framework for modeling system performance for the task–user–system interaction is also proposed. This will allow designers and evaluators of IVISs to make predictions about system performance and to design systems that meet a set of criteria for usable IVISs.

Context of use as a factor in determining the usability of in-vehicle devices

In recent years, the issue of usability of in-vehicle devices has received growing attention. This is in line with the increase in functionality of these devices, which has been accompanied by the introduction of various new interfaces to facilitate the user–device interaction. The complexity and diversity of the driving task presents a unique challenge in defining usability: user interaction with in-vehicle devices creates a ‘dual task’ scenario, in which conflicts can arise between primary and secondary driving tasks. This, and the safety-critical nature of driving, must be accounted for in defining and evaluating the usability of in-vehicle devices. It is evident that defining usability depends on the context of use of the device in question. The aim of this review therefore is to define usability for in-vehicle devices by selecting a set of criteria to describe the various factors which contribute to usability in this specific context of use.

Designing touchpad user-interfaces for vehicles: which tasks are most suitable?

Designers of in-vehicle computing systems must consider which input devices are most suitable for use in the safety-critical driving situation. This paper describes a study aiming to establish which tasks are best supported by an in-vehicle touchpad system. Eighteen participants (50:50 right/left handed) drove three routes in a right-hand drive simulator while following a lead vehicle at a perceived safe distance. At specific points, participants were asked to carry out seven tasks of varying qualities using a prototype touchpad system, a touchscreen or a rotary controller interface. Results indicated that participants were most negative (in terms of preferences and performance) with the rotary controller interface. Conversely, the results for the touchpad versus the touchscreen interfaces were clearly task dependent. For instance, with the touchpad, subjective opinions and objective performance were most positive for tasks in which simple commands enabled drivers to bypass the need for complex menu interactions (e.g. changing the interior temperature). In contrast, results for the touchscreen were evidently superior for simple menu selection tasks (e.g. selecting a preset radio station). Conclusions are drawn regarding the nature of tasks that are best suited to alternative input devices within vehicles and the potential for a touchpad/touchscreen solution.

Designing touchpad user-interfaces for right-hand drive vehicles: an investigation into where the touchpad should be located

Touchpads in vehicles offer a range of potential benefits over existing input devices, such as touchscreens. This article describes a study aiming to establish where a touchpad should be located within a right-hand drive vehicle. Sixteen participants (50:50 right/left handed) drove three routes in a right-hand drive simulator while following a lead vehicle at a perceived safe distance. At specific points, participants were asked to carry out three tasks of varying complexity using the touchpad. For each of the routes travelled, the touchpad was positioned in one of the three locations: in the centre console; in the door armrest and in the steering wheel. Differences in the performance and preferences of right-handed people vs. left-handed people were found. Right-handed people rated the door armrest location highly and made few glances towards this location while driving. In contrast, left-handed drivers were more positive towards the centre console location. The steering wheel location required a particularly high-visual demand. It is concluded that, for right-hand drive vehicles, a touchpad should be located in both the centre console and the door armrest to suit the diverse needs of the driver population.

Effects of Intuitive Voice Interfaces on Driving and In-vehicle Task Performance

This paper reported results of an on-road evaluation study of three types of voice interfaces, the traditional voice system, and two intuitive voice systems with text prompts on a central display and on a cluster display respectively. The effects of voice interfaces were evaluated based on primary driving and secondary in-vehicle task performance. The in-vehicle performance was characterized by the mean task duration and mean error rates in performing in-vehicle operations. It was found that the mean task duration was the shortest in using the intuitive voice system with cluster display and drivers made more errors when using the traditional voice system relative to intuitive voice systems. The error rates were the lowest when using intuitive voice system with cluster display. The visual distraction effects were examined in terms of glance percentage to the windscreen (road ahead) and number of glances towards the central display and the cluster display. Reductions in glance percentage to the windscreen were observed when using intuitive voice interfaces, accompanied by increases in glance percentage to the prompt display. The primary driving performance in using the three voice-activation interfaces was not significantly affected compared with baseline car following only situation. It is concluded that intuitive voice interfaces are a viable enhancement to traditional voice interface whilst intuitive voice interface with cluster display has relative advantages of good task performance and minor visual distraction.

Improving transmission reliability of low-power medium access control protocols using average diversity combining

Embedded computer systems equipped with wireless communication transceivers are nowadays used in a vast number of application scenarios. Energy consumption is important in many of these scenarios, as systems are battery operated and long maintenance-free operation is required. To achieve this goal, embedded systems employ low-power communication transceivers and protocols. However, currently used protocols cannot operate efficiently when communication channels are highly erroneous. In this study, we show how average diversity combining (ADC) can be used in state-of-the-art low-power communication protocols. This novel approach improves transmission reliability and in consequence energy consumption and transmission latency in the presence of erroneous channels. Using a testbed, we show that highly erroneous channels are indeed a common occurrence in situations, where low-power systems are used and we demonstrate that ADC improves low-power communication dramatically.

Vehicle-Driver Communication Using Off-the-Shelf Transceivers

Almost all modern cars can be controlled remotely using a personal communicator (keyfob). However, the degree of interaction between currently available personal communicators and cars is very limited. The communication link is unidirectional and the communication range is limited to a few dozen meters. However, there are many interesting applications that could be supported if a keyfob would be able to support energy efficient bidirectional longer range communication. In this paper we investigate off-the-shelf transceivers in terms of their usability for bidirectional longer range communication. Our evaluation results show that existing transceivers can generally support the required communication ranges but that links tend to be very unreliable. This high unreliability must be handled in an energy efficient way by the keyfob to car communication protocol in order to make off-the-shelf transceivers a viable solution

Human Vehicle Interaction Based On Electric Field Sensing

The intervention of a human body part entering the path between a low frequency transmit electrode and a receive electrode causes a change in the displaced current measured at the receive electrode. This method of human interaction with low frequency electric fields can be used to create a wide range of interactive applications including human computer interfaces, interactive surfaces, musical instruments, virtual reality and automotive applications. This paper presents a review of electric field sensing techniques and applications involving Human Vehicle Interaction (HVI). The HVI applications are split into three categories: proximity sensing and touch detection; gesture recognition; user discrimination.