Worldwide, the aging population will increase from 900 million (2015) to 2 billion by 2050 [1]. In Canada, it is expected to reach 15.1 million by 2063 [2]. Age-related changes, such as declining vision [3], reduced mobility [4], and cognitive decline, may hinder traffic signs recognition, decrease flexibility, and slow reaction times while driving [5], which can limit older adults’ ability to drive safely and travel independently [6]. Additionally, financial constraints [7], rural living [8], and small social networks [9] further restrict access to transportation options. These challenges increase the risk of sedentary behavior, isolation [10,11], loneliness [11], and anxiety [12]. To enable older adults to maintain their independence and engage in community life—key elements of social participation [13]—it is therefore essential to strengthen older adults’ ability to access and use transportation options that reflect their specific needs, including those involving emerging technologies.

Digital transportation planning tools (websites and apps) are intended to support users in accessing information, selecting transportation options, and organizing their travel. While these tools have the potential to improve mobility, they often pose considerable usability challenges for older adults. Age-related changes, such as decreased visual acuity [14], reduced contrast sensitivity [15], and diminished dexterity [16], can make it difficult for them to identify important interface elements, interpret maps, and accurately interact with touch or clickable components [17]. In addition to these sensory and motor declines [4], cognitive changes associated with aging, such as reduced executive functioning, can impair an individual’s ability to navigate complex transportation systems or coordinate multistep travel plans [6]. Digital literacy [18] also remains a key barrier; limited familiarity with technology can restrict access to real-time transportation updates or adaptive features within e-tools [19]. Differences in numerical comprehension and screen navigation further emphasize the need for design solutions that reflect the diverse abilities of this population [20].

Beyond usability considerations, digital transportation planning tools may influence older adults’ mobility and well-being through psychological and cognitive mechanisms. Accessible and intuitive interfaces can reduce cognitive demands, helping users process information more efficiently and make travel decisions with less effort [21]. This may enhance perceived control over travel and strengthen mobility-related self-efficacy, understood as confidence in one’s ability to plan and complete trips, particularly because older adults’ transition to public transit use involves acquiring travel-planning skills and confidence through experience [22]. Together, greater perceived control and self-efficacy may encourage more frequent and independent use of transportation options, supporting social participation and well-being. Conversely, poorly designed interfaces may increase cognitive burden, reduce confidence, and discourage engagement with transportation systems [23].

Addressing such specific needs of older adults is vital for creating inclusive tools that enhance their user experience and support independent mobility. A participatory design approach is especially valuable for ensuring that these needs are fully integrated into the development and evaluation of transportation planning interfaces. Participatory design, sometimes known as cocreation or co-design [24], is described as a collaborative process in which various participants engage in shared exploration, understanding, and learning through ongoing reflection and action [25]. Among other benefits, participatory design contributes to a better user experience, as it is conceived with the end users in mind rather than simply tested by them [26]. User experience is defined as “an iterative set of decisions leading to a successful outcome with an interactive tool, as well as a productive and satisfying process to achieve that outcome” [27]. To enhance the user experience of older adults when using a travel planning e-tool, it is important to design an interface that is specifically adapted to their specific needs and allows them to perform their intended tasks easily, intuitively, and without confusion or interruption [28]. Given the notable lack of studies specifically focused on developing and evaluating transport planning interfaces tailored to the needs and preferences of older adults through a participatory design approach [28], addressing this gap is essential for enhancing their user experience with transportation planning e-tools.

The aim of this study is to improve older adults’ experience in using a transportation planning e-tool—called Mobilaînés—by co-designing its interface and evaluating its usability and user experience based on their needs and preferences. Rather than introducing a new mode of transportation, Mobilaînés [29] was designed to integrate existing options, helping older adults make informed travel decisions and supporting their autonomy in everyday life, using a living laboratory methodology [30]. The study took place in Sherbrooke, a city in the province of Quebec, Canada, characterized by its hilly terrain, and its main public transportation is an urban bus service. These environmental characteristics may create mobility challenges for older adults, especially those with reduced endurance, mobility limitations, or unfamiliarity with public transit. In addition, despite increasing digital technology use among older adults in Canada, digital literacy, confidence, and access remain uneven, particularly among those with functional or social vulnerabilities [31]. This context highlights the need for transportation planning tools adapted to older adults’ capabilities and preferences. The Mobilaînés living laboratory methodology, as well as its algorithm development, is described elsewhere (see Provencher et al [29] and Tahir et al [32] for additional details). The study is guided by the following research question: How does the co-designed Mobilaînés transportation planning interface improve usability and user experience for older adults?

Using a participatory design approach [29], the study had 2 phases using qualitative and quantitative methods: the development phase (May 2020 to July 2022), which focused on the co-design process to ensure that older adults’ needs and preferences were considered, and the evaluation phase (August 2022 to August 2024), which examined the usability and user experience of the interface prototype to ensure alignment of the e-tool with the expectations of older adult users (Figure 1).

The effects of using the Mobilaînés prototype on older adults’ participation in meaningful activities in real-life contexts were explored. Participants (n=4), recruited using the same criteria as in previous usability tests, used the prototype over 6 weeks. Each completed a 1-hour individual introductory session, during which key functions, including account creation, trip planning, saving, and printing, were demonstrated and practiced. Two tutorial videos in French and English were uploaded to the Mobilaînés YouTube channel and emailed to participants to support use and personalization. In weeks 1, 3, and 5, participants were asked by phone to plan trips to 3 Sherbrooke locations; in weeks 2, 4, and 6, the user experience expert followed up by phone to encourage use and address difficulties. Participants were asked to use the tool at least once per week. In weeks 1 and 5, participants completed a paper version of the User Experience Questionnaire (UEQ; Multimedia Appendix 5) to assess satisfaction with the e-tool and changes in user experience over time [50]. The UEQ uses a 7-point Likert scale to assess 6 dimensions: Attractiveness, Perspicuity, Efficiency, Dependability, Stimulation, and Novelty [51] (Multimedia Appendix 6). It has acceptable-to-good reliability (Cronbach α=0.77‐0.92) and construct validity, with correlations between pragmatic and hedonic factors of r=0.42 (P<.001), and attractiveness correlating strongly with pragmatic (r=0.82) and hedonic (r=0.65) user experience aspects (P<.001). After 6 weeks, participants were invited to final interviews about their use of Mobilaînés, its support or lack of support for meaningful activities, and barriers and facilitators in travel planning and daily participation (Multimedia Appendix 7).

To address the first objective, selected e-tools (Vermeille app or website, Google Maps app or website, Moovit app, and OC Transpo website) were heuristically evaluated for compatibility with age-friendly usability guidelines. Compatibility was assessed descriptively across phases using the same age-friendly usability guideline framework. Applicable guidelines were classified as compatible or noncompatible, and compatibility percentages were calculated as the number of compatible guidelines divided by total applicable guidelines, multiplied by 100. Using the same framework and calculation method allowed for descriptive comparison across phases. However, the evidence used to assess compatibility differed by phase: during development, compatibility was assessed through expert heuristic evaluation, whereas during laboratory and in-field evaluations, observed usability issues, participant feedback, and evaluation findings were mapped to the same framework. An iterative deductive thematic analysis [52] was conducted by SBG on the verbatim transcripts from the cocreation workshops with older adults, using the age-friendly usability design principles and guidelines [39].

To address the second objective, descriptive analyses of participant characteristics, performance metrics, and SUS, UTAUT, and UEQ scores were conducted in SPSS (IBM Corp). SUS scores below 60 were considered unacceptable, and scores of 90 or above were considered excellent [48]. For UTAUT, a score of 3 on the 5-point Likert scale was treated as the acceptable reference value for each construct item. Focus groups and interviews were recorded, transcribed, imported into NVivo (version 20; Lumivero), and analyzed by SBG using constant comparison, deductively for usability tests and inductively for the in-field test, through open, axial, and selective coding [53]. Given the small sample sizes in the laboratory usability tests and in-field test, all quantitative findings were interpreted descriptively, and no inferential comparisons were conducted between tests. Mean and SD values were retained for questionnaire scores to remain consistent with common reporting practices for the SUS, UTAUT, and UEQ; however, these values were interpreted cautiously.

Ethical approval was obtained from the CIUSSS de l’Estrie-CHUS (2020‐3389: MOBILAÎNÉS). All participants provided written informed consent after being informed about the study aims and procedures. To protect privacy and confidentiality, data were coded and deidentified during collection, analysis, and reporting. Consent forms and the code key were kept securely in a locked location by the researcher in charge. Research data, including audio and video recordings, were stored confidentially in a locked location for 5 years by the principal investigator (VP). Participants in co-design workshops and laboratory usability tests received US $15 per session, with parking reimbursement when applicable; in-field test participants received US $75 each.

This study sought to enhance the experience of older adults using a transportation planning e-tool by developing an interface grounded in their needs and preferences through a participatory approach. The process focused on 2 objectives: co-designing an interface with older adults and evaluating its usability and user experience. The compatibility of the Mobilaînés e-tool with age-friendly design guidelines increased descriptively from 67% to 95% through iterative mock-up development and usability tests. These improvements were reflected in user experience scores, moving from unacceptable to very good.

The compatibility of the Mobilaînés e-tool with age-friendly heuristics aligns with findings by Patsoule and Koutsabasis [54], who identified Visibility and Ease of Understanding as the 2 primary heuristics tailored to older adults in website redesign. A clear and intuitive interface can significantly reduce cognitive load for older adults when interacting with digital tools, making tasks more manageable and less stressful [55]. Our results are also in line with those of Hart et al [47], who suggested that improvements to increase design compatibility with guidelines contributed to a more user-friendly experience for older adults. In our study, in-field test participants expressed a high level of satisfaction with the website’s interface, which was easy to use and well suited to their travel planning needs. UEQ results showed that after several weeks of use, participants found the Mobilaînés e-tool more interesting, practical, and easy to use for travel planning. With repeated use, they also perceived it as more attractive, efficient, and trustworthy, encouraging more spontaneous and sustained engagement. However, one participant noted the absence of real-time travel and traffic information, which would have allowed tracking of their bus journey and arrival times. This limitation was observed across all 3 usability evaluations and relates to the Information principle in usability design guidelines. Although the travel plan printing feature does not offer real-time updates, its visual and informative format ensures accessibility for all older adults, regardless of digital proficiency. For older adults who may experience heightened anxiety from unexpected travel disruptions, Citroen [56] emphasizes that access to up-to-date information can significantly reduce stress and improve decision-making. Incorporating such features not only enhances the tool’s practicality but also strengthens user confidence and satisfaction—key factors in promoting adoption and sustained use.

Interpreted through the UTAUT model [49], the design refinements implemented in Mobilaînés may help explain improvements in usability and acceptance. Step-by-step navigation, simplified task flow, familiar terminology, and clearer feedback may have supported effort expectancy by reducing the perceived difficulty of use. Personalized route-planning options, such as saved addresses and walking preferences, may have strengthened performance expectancy by making the tool more useful for users’ everyday travel needs. Clear structured guidance may also represent facilitating conditions by helping users complete tasks with greater confidence. From a behavior change perspective [57], these features may support perceived capability and confidence in planning trips independently, which may encourage future use and engagement in community mobility.

However, achieving these improvements required several design and evaluation cycles, highlighting the time and resources needed to develop age-friendly e-tools through participatory and iterative approaches [58]. Qualitative data further highlighted the tool’s reliability, accessibility, and effectiveness for transportation planning, despite limitations such as the absence of real-time data. Overall, these findings emphasize the value of involving older adults throughout the design and evaluation process to ensure that the Mobilaînés e-tool is closely attuned to their lived experiences and everyday contexts [58,59].

The in-field test results further revealed that Mobilaînés reduced participants’ travel-related concerns by helping them anticipate each step of their journey and boosting their confidence in reaching unfamiliar destinations or adopting new modes of transport, particularly when transitioning away from car use. Although the destinations and usage period of the Mobilaînés tool were predetermined, participants reported that it enhanced trip predictability and served as a reliable resource for leaving their homes independently. In line with behavior change theory [57] and the Technology Acceptance Model [60], generating positive emotions, such as feeling safe and anticipating the pleasure of reaching a destination, may encourage sustained use of Mobilaînés. Greater ease of use enhances the overall experience, which can in turn support older adults’ independence, social participation, and overall quality of life [61]. According to Schroeder et al [62], older adults’ intention to adopt technology is notably influenced by awareness, emotional needs, and motivational aspects. Understanding these motivators is essential, as personal desire drives activities such as visiting family, whereas medical appointments are often perceived as obligatory [63]. This finding highlights the potential of Mobilaînés to not only facilitate independent mobility but also foster sustained engagement in meaningful daily activities by aligning technological support with older adults’ emotional and motivational needs.

The main contribution of this study is not limited to the development of a transportation planning e-tool; rather, it lies in generating practical design lessons for age-friendly transportation planning interfaces. Through an iterative co-design and evaluation process, this study identifies concrete design decisions related to navigation, feedback, visual clarity, personalization, and route information that can inform the development of future digital transportation tools for older adults.

This study faced several limitations. First, recruitment challenges resulted in an overrepresentation of tech-savvy participants (Solange personas) and an underrepresentation of those with lower digital literacy (Leonard and René personas). This imbalance may have influenced usability outcomes and should be considered when interpreting the findings. The use of personas also requires caution, as they can simplify the diversity of older adults’ experiences if they are not continuously grounded in lived experience. In this study, personas were developed based on interviews, literature, and stakeholder workshops, and were used as design tools to guide recruitment, scenario development, and interface decisions. However, the overrepresentation of participants corresponding to the Solange persona may have influenced design priorities, limiting the representation of other mobility and digital literacy profiles. Additionally, the small sample size in the laboratory usability tests (n=5 and 7) and particularly in the in-field test (n=4) warrants caution regarding the generalizability and transferability of the findings. The in-field results should therefore be interpreted as exploratory, providing preliminary insight into real-world use rather than definitive evidence of sustained effectiveness. Moreover, comparisons between the 2 laboratory usability tests should be interpreted descriptively, as they involved different participants and participant profiles, with the second test including only those participants corresponding to the Solange persona. Therefore, observed improvements in performance metrics, SUS, UTAUT, and UEQ scores may reflect both interface refinements and differences in participant characteristics, rather than generalizable evidence of effectiveness. Several strategies were used to promote recruitment, such as online advertisements, poster distribution, and the use of local databases. However, given the risks of fraud associated with soliciting older adults by phone or online [64], recruitment through trusted individuals or community partners may be particularly important in future studies [65]. Moreover, flexible scheduling regarding time and place helped to reduce withdrawal due to health reasons, which is common in participatory approaches involving older adults [66,67].

Second, resource constraints affected the feasibility of conducting a broader summative evaluation, such as involving multiple independent evaluators for heuristic analysis. The iterative co-design process required more design and evaluation cycles than anticipated, creating challenges related to time, resources, and project continuity. This highlights the need to plan sufficient resources and procedural continuity from the outset, as the number of refinement cycles can be difficult to predict. To support methodological rigor, usability issues were reviewed with interdisciplinary team members during key development and evaluation phases to help reduce interpretation bias [68]. Design issues were prioritized according to their relevance to age-friendly usability principles, potential impact on task completion and user experience, and feasibility within project constraints.

From a reflexivity and positionality perspective, the analysis and design decisions were shaped by an interdisciplinary team with expertise in user experience, rehabilitation, gerontology, communication, and computer science. While this positioning supported a multidimensional interpretation of the findings, it may also have influenced how usability issues were identified and prioritized. To reduce this risk, interpretations were informed by multiple sources of evidence, including heuristic evaluation results, older adults’ feedback, performance metrics, questionnaire results, focus groups, and interviews.

Future studies should address key challenges identified during the development and evaluation of the Mobilaînés application. First, integrating real-time travel and traffic data is essential for effective trip planning [69], reducing anxiety about getting lost [10], protecting against adverse weather and traffic [70,71], and supporting transport choices aligned with individual needs [72]. Features not yet implemented, such as avoiding icy roads, could be enhanced through technical solutions and partnerships, improving adaptation to real-life mobility challenges and addressing safety concerns for pedestrians using mobility devices in winter conditions [73-75].

Second, future research should examine design approaches that support adoption and long-term routinization among older adults with diverse mobility, social participation, and digital literacy profiles. Interview and focus group findings suggested that accessibility features, such as pairing icons with text labels and using familiar visual cues, may benefit all users while supporting age-related visual decline and novice users, such as those represented by the René and Suzana personas. Older adults’ technology adoption is shaped by prior experience, available support, perceived usefulness, confidence, and comfort [21]. For Mobilaînés, these factors may involve reliability, accurate real-time and offline information, auditory guidance, and cues that provide ongoing support or training. Universally accessible systems responsive to older adults’ needs can improve usability and user experience, thereby encouraging adoption and sustained engagement [76,77]. Finally, future studies should include longitudinal evaluations of spontaneous and sustained real-world use beyond structured, researcher-supported testing to assess long-term impacts on meaningful activities, gradual behavioral changes, and infrequent travel needs, such as medical appointments.

Given the aging population and the critical role of mobility in health outcomes [78], this study addresses a key knowledge gap by advancing age-friendly digital transport planning. Using a participatory approach, the Mobilaînés e-tool was developed and evaluated with older adults to ensure that the interface aligned with their needs and preferences. A key contribution of this study is the identification of concrete design improvements, such as step-by-step task flow, clearer navigation, enhanced visual cues and feedback, structured route information, and personalization of travel preferences that support a more age-friendly planning experience. Findings highlight the need for iterative refinement to reduce cognitive load, support meaningful engagement, and promote digital inclusion, while guiding the development of accessible transport technologies for older adults. Future research should examine human-centered and technological strategies to foster adoption and sustained use, particularly among users with limited digital literacy.