Design for behavioural change: study of a concept and recommendations for information systems supporting eco-driving

This work focuses on the design of driver Human-Machine Interface (HMI) for electric vehicles (EVs) eco-driving, with a specific emphasis on designing for behavioural change. Behavioural change may play a crucial role in promoting sustainable driving practices and reducing energy consumption.

This thesis tackles the urgent environmental issues of global warming, urban air pollution, and biodiversity loss by targeting the human behaviours that exacerbate these problems. Recognizing that technological advancements in energy efficiency alone are insufficient, this research explores the design of innovative Human-Machine Interfaces (HMIs) for electric vehicles (EVs) to promote eco-driving and reduce energy consumption. Guided by the objectives to determine if nudging can improve energy-saving behaviour in EV drivers, to explore how motivation can drive long-term behaviour change, and to contribute to existing theories on nudging eco-behaviour for EVs, this study employs a comprehensive approach.

The research involved three empirical studies grounded in theories of EV eco-driving, data visualization, information framing, goal setting, and nudging. The studies revealed critical insights into the design of effective HMIs for promoting sustainable driving behaviours.

Study 1 utilized a co-design methodology to identify key features and user behaviours essential for eco-driving. Participants emphasized the importance of performance feedback and goal-setting tools, laying the groundwork for the development of user-centred HMI concepts.

Study 2a explored the impact of framing (positive vs. negative) on users' motivation to engage in energy-saving behaviours. Although quantitative results showed no significant differences, qualitative insights revealed that users respond positively to gamification, immediate feedback, and clear communication of economic and environmental benefits. These findings underscore the necessity of a multifaceted approach to HMI design.

Study 2b examined the influence of preset default values on goal-setting behaviour. The study confirmed that higher defaults lead to more ambitious energy-saving goals, demonstrating the powerful anchoring effect of defaults. Interestingly, it was found that defaults had a stronger impact than pro-environmental attitudes, suggesting that well-designed defaults can effectively guide behaviour regardless of users' initial environmental inclinations.

Study 3 refined these concepts through iterative design and validation. In Study 3a, co-design sessions using LEGO® Serious Play® (LSP) led to the creation of two gamified HMI LEGO® prototypes: "Grow Your Garden" (GYG) and "Green Regatta" (GR). The GYG interface leveraged collaborative engagement by visualizing eco-driving progress as a growing digital garden, fostering intrinsic motivation and collective responsibility. GR employed competitive gamification, transforming eco-driving achievements into progress within a virtual sailing race. These interfaces reflected distinct motivational profiles—collaborative and competitive—rooted in user-driven insights.

Building on these prototypes, Study 3b validated the interfaces in a simulated smartphone app environment, emphasizing the critical role of usability testing in HMI design. Participants interacted with the GYG and GR interfaces through a smartphone-based simulation, replicating real-world use scenarios. This phase assessed user engagement, motivational effectiveness, and design resonance. GYG demonstrated strong potential for sustained eco-driving behaviours by combining personal rewards with collective environmental goals, while GR was effective in engaging users through performance-oriented feedback.

The thesis contributes significantly to HMI design for EVs by advancing the integration of nudging, goal-setting, and gamification strategies. It highlights the importance of aligning individual and collective motivations to promote sustainable behaviours. Practically, the findings provide actionable insights for designers and manufacturers to create engaging and user-centred HMIs that drive eco-driving and reduce energy consumption.

By bridging theoretical frameworks with practical applications, this research not only advances the field of HMI design but also underscores the transformative potential of technology in fostering environmental stewardship. These findings serve as a guide for future innovations in sustainable interface design, contributing to broader ecological goals and the collective effort to combat climate change.