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

A Vehicle Simulation Study Examining the Effects of System Interface Design Elements on Performance in Different Vibration Environments Below 3 Hz

OBJECTIVE

This study aimed to explore the relationship between system interface elements' design features and interaction performance in simulated vehicle vibration environments.

BACKGROUND

Touch screens have been widely used in vehicle information systems, but few studies have focused on the decline of touchscreen interaction performance and task load increase when driving on unpaved roads.

METHOD

The interaction performance (reaction time and task accuracy rate) with vibration frequencies below 3 Hz (1.5, 2.0, and 2.5 Hz) and different interface design elements was investigated employing a touch screen computer and E-prime software.

RESULTS

The results indicate that vehicle vibration (below 3 Hz) can significantly reduce interaction performance with a vehicle information system interface.

CONCLUSION

An appropriate increase in the physical size of the interface design features (visual stimulus materials and touch buttons) can help to mitigate this negative effect of vibration.

APPLICATION

The results and findings of this study can be utilized for the design of information system interfaces as it relates to the vibration scenario of unpaved roads.

Assessing driver distraction from in-vehicle information system: an on-road study exploring the effects of input modalities and secondary task types

In-vehicle information system (IVIS) use is prevalent among young adults. However, their interaction with IVIS needs to be better understood. Therefore, an on-road study aims to explore the effects of input modalities and secondary task types on young drivers' secondary task performance, driving performance, and visual glance behavior. A 2 × 4 within-subject design was undertaken. The independent variables are input modalities (auditory-speech and visual-manual) and secondary task types (calls, music, navigation, and radio). The dependent variables include secondary task performance (task completion time, number of errors, and SUS), driving performance (average speed, number of lane departure warnings, and NASA-TLX), and visual glance behavior (average glance duration, number of glances, total glance duration, and number of glances over 1.6 s). The statistical analysis result showed that the main effect of input modalities is significant, with more distraction during visual-manual than auditory-speech. The main impact of secondary task types was also substantial across most metrics, aside from average speed and average glance duration. Navigation and music were the most distracting, followed by calls, and radio came in last. The distracting effect of input modalities is relatively stable and generally not moderated by the secondary task types, except radio tasks. The findings practically benefit the driver-friendly human-machine interface design, preventing IVIS-related distraction.

Chinese handwriting while driving: Effects of handwritten box size on in-vehicle information systems usability and driver distraction

OBJECTIVE

Handwritten box size (HBS) is an essential Chinese handwriting interface element when interacting with touchscreen-based in-vehicle information systems (IVISs) since it is compactly bound up with driver distraction besides usability issues. Miscellaneous HBSs are commercially available on IVISs, yet the details of how the drivers interact with them in an in-vehicle display situation remain sparsely examined. Therefore, this study set out to investigate the effects of HBS on IVISs usability (task completion time, number of errors, number of protruding strokes, and NASA-TLX, a subjective workload assessment tool) and driver distraction (mean speed, lane position variation, total glance time, number of glances, mean glance time, and number of glances exceeding 1.6 s). Ultimately, the appropriate HBS on IVISs is determined.

METHODS

A simulated driving experiment involving thirty drivers was launched. The primary task was lane-keeping with speed ranging from 40 to 60 km/h, and the secondary task was entering a 5-character text by Chinese handwriting input under five different HBS conditions: 25 × 25 mm, 30 × 30 mm, 35 × 35 mm, 40 × 40 mm, and 45 × 45 mm. A battery of one-way repeated measure analyses of variance (r-ANOVA) was used to examine which HBS can maximize IVISs usability and minimize driver distraction with the smallest HBS.

RESULTS

Generally, the issues of IVISs usability and driver distraction improved progressively as the HBS increased to a specific size (40 × 40 mm in this study), at which they got to the asymptotes. Specifically, HBS below 40 × 40 mm was associated with longer text input time, more errors and protruding strokes, extended eyes-off-road time, excessive off-road glances, and deteriorative lateral driving performance. Nevertheless, there were no significant differences in mean glance time and longitudinal driving performance. No improvement measures were observed for HBS above 40 × 40 mm, except for a higher perceived workload.

CONCLUSIONS

Overall, the appropriate HBS of in-vehicle Chinese handwriting was found to be 40 × 40 mm. Considering that the in-vehicle human-machine interface (HMI) has limited display space and increasing visual complexity, these findings may help develop evidence-based design guidelines for driver-friendly IVISs and prevent distracted-related traffic injuries.

Data-Driven Usability Assessment Model for Smartphones: A Causal Analytic Approach

Usability is an emerging subject for smartphone design and service, which results in the overall quality and achievement of a product and allows users to perform various tasks. In this context, this study aims to propose an integrated smartphone usability framework for higher service level and user experience with a causal analytic approach. Involving tested relationships with theoretical concerns a conceptual usability assessment model is proposed including design, customer focus, quality, innovation, usability, and user perception variables. The provided model is developed using the Bayesian neural networks based universal structure modeling (USM) method. The reliability and validity are empirically tested for the questionnaire data collected from 1068 smartphone users. The results and findings showed that design, customer focus, quality, and innovation explain usability, and user perception as an ultimate variable is interpreted by usability. Also, strategic, and valuable information for smartphone designers and marketing people to understand user perceptions for smartphone usability is provided.

Usability: Adoption, Measurement, Value

OBJECTIVE

We searched for the application of usability in the literature with a focus on adoption, measurements employed, and demonstrated value. Five human factors domains served as a platform for our reflection, which included the last 20 years.

BACKGROUND

As usability studies continue to accumulate, there has been only a little past reflection on usability and contributions across a variety of applications. Our research provides a background for general usability, and we target specific usability research subareas within transportation, aging populations, autistic populations, telehealth, and cybersecurity.

METHOD

"Usability" research was explored across five different domains within human factors. The goal was not to perform an exhaustive review but, rather, sample usability practices within several specific subareas. We focused on answering three questions: How was usability adopted? How was it measured? How was it framed in terms of value?

CONCLUSION

We found that usability is very domain specific. Usability benchmarking studies and empirical standards are rare. The value associated with improving usability ranged widely-from monetary benefits to saving lives. Thus, researchers are motivated to further improve usability practices. A number of data collection and interpretation challenges still call for solutions.

APPLICATION

Findings offer insight into the development of usability, as applied across a variety of subdomains. Our reflection ought to inform future theory development efforts. We are concerned about the lack of established benchmarks, which can help ground data interpretation. Future research should address this gap in the literature. We note that our findings can be used to develop better training materials for future usability researchers.

Ideation using the "Design with Intent" toolkit: A case study applying a design toolkit to support creativity in developing vehicle interfaces for fuel-efficient driving

Everyday driving is a significant source of greenhouse gases and pollutants within developed nations. Finding ways to combat these emissions and minimise the impact of anthropometric climate change is a growing challenge for all research disciplines. This current paper explores the use of a design toolkit "Design with Intent" to generate ideas for in-vehicle interfaces designed to reduce fuel use and emissions. A preliminary interface validation assessment is also presented in order to assess whether the ideas generated were appropriate in encouraging behavioural change and of potential value. It is suggested that whilst further evaluation of the interfaces are required, the use of the "Design with Intent" toolkit facilitated the creative process, allowing engineers to conceive initial interface designs in a creative manner.

Competition and Game of the Pre-Installed Market and Post-Installed Market of the Internet of Vehicles from the Perspective of Cooperation

The Internet of Vehicles market is broadly divided into two parts—the pre-installed market and the post-installed market. Although they possibly have cooperative relationships, there is a competition game between them in terms of interests, and a healthy game relationship can promote the optimization of products and the overall improvement of the service level in the Internet of Vehicles market. Through the evolutionary game model, this article analyzes the dynamic game process between the pre-installed market and the post-installed market of the Internet of Vehicles, explores the various evolution trends of the Internet of Vehicles market from the perspective of cooperation, and combines the numerical simulation analysis to study the three possible evolutionary trends and corresponding steady states. The results show that, when the cooperation ratio is relatively high, both sides of the game are in the cyclical competition and game, which is the optimal competition state of the Internet of Vehicles market. On the contrary, any kind of “steady state” is unfavorable to the overall market. Therefore, all parties should be encouraged to establish a deeper level of cooperation and jointly promote the further prosperity of the Internet of Vehicles market in the process of cooperation and competition.

Creating the environment for driver distraction: A thematic framework of sociotechnical factors

As modern society becomes more reliant on technology, its use within the vehicle is becoming a concern for road safety due to both portable and built-in devices offering sources of distraction. While the effects of distracting technologies are well documented, little is known about the causal factors that lead to the drivers' engagement with technological devices. The relevance of the sociotechnical system within which the behaviour occurs requires further research. This paper presents two experiments, the first aims to assess the drivers self-reported decision to engage with technological tasks while driving and their reasoning for doing so with respect to the wider sociotechnical system. This utilised a semi-structured interview method, conducted with 30 drivers to initiate a discussion on their likelihood of engaging with 22 different tasks across 7 different road types. Inductive thematic analysis provided a hierarchical thematic framework that detailed the self-reported causal factors that influence the drivers' use of technology whilst driving. The second experiment assessed the relevance of the hierarchical framework to a model of distraction that was established from within the literature on the drivers use of distracting technologies while driving. The findings provide validation for some relationships studied in the literature, as well as providing insights into relationships that require further study. The role of the sociotechnical system in the engagement of distractions while driving is highlighted, with the causal factors reported by drivers suggesting the importance of considering the wider system within which the behaviour is occurring and how it may be creating the conditions for distraction to occur. This supports previous claims made within the literature based model. Recommendations are proposed that encourage a movement away from individual focused countermeasures towards systemic actors.

Sonification of in-vehicle interface reduces gaze movements under dual-task condition

In-car infotainment systems (ICIS) often degrade driving performances since they divert the driver's gaze from the driving scene. Sonification of hierarchical menus (such as those found in most ICIS) is examined in this paper as one possible solution to reduce gaze movements towards the visual display. In a dual-task experiment in the laboratory, 46 participants were requested to prioritize a primary task (a continuous target detection task) and to simultaneously navigate in a realistic mock-up of an ICIS, either sonified or not. Results indicated that sonification significantly increased the time spent looking at the primary task, and significantly decreased the number and the duration of gaze saccades towards the ICIS. In other words, the sonified ICIS could be used nearly exclusively by ear. On the other hand, the reaction times in the primary task were increased in both silent and sonified conditions. This study suggests that sonification of secondary tasks while driving could improve the driver's visual attention of the driving scene.

Psychometric properties of the persian language version of the system usability scale

BACKGROUND

The System Usability Scale (SUS) is a widely used self-administered instrument for evaluating the usability of a wide range of products and services. The aims of this descriptive-methodological study were to develop and investigate the psychometric properties of the Iranian version of the SUS.

METHODS

The study was conducted among 202 university students from the Tabriz University of Medical Sciences, Iran. Content validity was evaluated by a panel of 10 experts. Construct validity was assessed by exploratory and confirmatory factor analyses. The internal consistency and test-retest reliability were assessed by Cronbach's alpha and Intraclass Correlation Coefficient (ICC), respectively. Additionally the feasibility of the measure was judged by ceiling and floor effect.

RESULTS

Content validity of the short form of Iranian SUS was established. Factor analyses supported the conceptual uni-dimensionality, and thus confirmed the construct validity of the measure. The internal consistency (α = 0.79) and test retest reliability (ICC = 0.96) were both approved and there was also no ceiling nor floor effect.

CONCLUSIONS

The findings support the use of SUS for both practical and research settings in Iranian population.

Modelling the hare and the tortoise: predicting the range of in-vehicle task times using critical path analysis

Analytic models can enable predictions about important aspects of the usability of in-vehicle information systems (IVIS) to be made at an early stage of the product development process. Task times provide a quantitative measure of user performance and are therefore important in the evaluation of IVIS usability. In this study, critical path analysis (CPA) was used to model IVIS task times in a stationary vehicle, and the technique was extended to produce predictions for slowperson and fastperson performance, as well as average user (middleperson) performance. The CPA-predicted task times were compared to task times recorded in an empirical simulator study of IVIS interaction, and the predicted times were, on average, within acceptable precision limits. This work forms the foundation for extension of the CPA model to predict IVIS task times in a moving vehicle, to reflect the demands of the dual-task driving scenario.

PRACTITIONER SUMMARY

The CPA method was extended for the prediction of slowperson and fastperson IVIS task times. Comparison of the model predictions with empirical data demonstrated acceptable precision. The CPA model can be used in early IVIS evaluation; however, there is a need to extend it to represent the dual-task driving scenario.

The implications of cross-regional differences for the design of In-vehicle Information Systems: a comparison of Australian and Chinese drivers

The increasing global distribution of automobiles necessitates that the design of In-vehicle Information Systems (IVIS) is appropriate for the regions to which they are being exported. Differences between regions such as culture, environment and traffic context can influence the needs, usability and acceptance of IVIS. This paper describes two studies aimed at identifying regional differences in IVIS design needs and preferences across drivers from Australia and China to determine the impact of any differences on IVIS design. Using a questionnaire and interaction clinics, the influence of cultural values and driving patterns on drivers' preferences for, and comprehension of, surface- and interaction-level aspects of IVIS interfaces was explored. Similarities and differences were found between the two regional groups in terms of preferences for IVIS input control types and labels and in the comprehension of IVIS functions. Specifically, Chinese drivers preferred symbols and Chinese characters over English words and were less successful (compared to Australians) at comprehending English abbreviations, particularly for complex IVIS functions. Implications in terms of the current trend to introduce Western-styled interfaces into other regions with little or no adaptation are discussed.

A comparison of two contemporary types of in-car multifunctional interfaces

A driving simulator study was conducted to investigate the effects of carrying out a variety of tasks using two different types of contemporary in-car multifunctional interfaces: a touch screen interface and an interface manoeuvred by a rotary control. Participants drove on a curved rural road while performing tasks such as list scrolling, radio tuning, alphanumeric input and continuous adjustments. The results indicate that, in terms of task completion time and the number of glances made to the display, the optimal interface is dependent on the task being performed. The touch screen interface was better for alphanumeric input tasks and the interface manoeuvred by a rotary control was better for continuous adjustments and list scrolling. Alphanumeric input seems to be more demanding than other tasks, independent of the interface used. It was apparent in this simulator study that both interfaces affected the lateral control performance, but lateral control performance deteriorated to a greater extent when the touch screen interface was used, probably partially as a result of the lower display position.

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.