The population of individuals aged 65 years and above is projected to increase from 900 million in 2015 to 2 billion by 2050 [1]. Recent data reported that 37.8% of Canadians over the age of 65 years live with a disability, which increases mobility issues in their daily travel [2]. Indeed, some age-related changes may impede the use of transportation for many older adults to participate in meaningful activities. Decreased vision [3-5] and hearing loss [6,7] make it difficult to see other road users (especially at night), recognize traffic signs (reading text and distinguishing colors) while driving, and hear high-frequency sounds when crossing the street. In addition, decreased flexibility, range of motion, and grip strength can limit driving control and impair driving safety [7], which makes it difficult for them to get around. Therefore, it is necessary to support the ability of older adults to know and use transportation options that are tailored to their needs so that they continue to be able to leave their homes, which is an essential characteristic of social participation [8].

Transportation-planning e-tools are currently available to provide older adults with information about transportation and trip options. These tools can take the form of websites or applications designed to assist users in planning, personalizing, and managing their travel. However, many older adults find them challenging to use. With increased aging, reduced dexterity and lower vision make it difficult to locate the necessary information on the screen or click on the appropriate button, which can impede their experience when planning travels in the community [9]. Specifically, visual decline also impacts the contrast sensitivity in using travel planning e-tools (eg, recognizing the elements in maps or e-tools). The decline of fine motor skills [4] may interfere with the use of electronic devices that allow movement planning. Moreover, lower executive abilities can lead to difficulty in planning travel and understanding public transportation options [10]. Besides, some older adults experience difficulty in travel planning due to their lack of digital literacy [11], which may raise challenges, such as access to the up-to-date flow of information for travel planning [12]. The interface of the developed tool should thus consider these age-related changes and the variability in numerical literacy [13] in planning trips. When it comes to designing an interface, user experience is essential [14].

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 while arriving at this outcome” [15]. According to Hassenzahl and Tractinsky [16], it is created by the interaction of the user’s internal state, the characteristics of the designed system, and context. It should be noted that 2 other concepts should be introduced in relation to user experience: user interface and usability. User interface is “the part of technology that people interact with. The interaction between a computer and a user is a two-way interaction” [17]. Therefore, user interface design refers to “the iterative set of decisions leading to a successful implementation of an interactive tool” [15]. Usability refers to the fact that “when a product or service is truly usable, the user can do what she or he wants to do, the way she or he expects to be able to do it, without hindrance, hesitation or questions” [18]. Hassan and Galal-Edeen [19] argue that usability is a subset of user experience, and none alone can determine the degree of conformity of a product or service to the expectations and needs of its users. The usability criteria include usefulness, efficiency, effectiveness, satisfaction, learnability, accessibility, memorability, and error tolerance. Considering these definitions in the framework of this study, the user experience refers to the interaction of older adults with the aesthetic and functional aspects of the transportation planning e-tool to plan a trip that satisfactorily meets their needs and preferences.

A co-design design is a participatory approach that can be relevant to older adults to address their challenges in planning a trip and improve the user experience when using e-tools. Participatory design refers to “a process of investigating, understanding, reflecting upon, establishing, developing, and supporting mutual learning between multiple participants in collective reflection-in-action” [20]. Understanding the interactions and collaboration of older adults in co-design approaches such as participatory design [20] is an important aspect of user experience design [21] as older adults’ needs and physical condition can affect their participation in the design process. Participatory design could help evaluate user experience. As there is a lack of research on user experience design for older adults [22], it is essential to support older adults’ mobility through travel options that are tailored to their needs and preferences by identifying knowledge gaps regarding the user experience design of older adults when using a transportation planning e-tool.

The aim of this scoping review is to identify knowledge gaps regarding the user experience design and its evaluation for older adults using transportation planning e-tools.

This scoping review was based on Arksey and O’Malley’s [23] framework with the following stages: (1) identifying the research question; (2) identifying the relevant sources; (3) selecting the studies; (4) charting the data; and (5) collecting, summarizing, and reporting results.

The question was formulated using a broad approach to ensure sufficient breadth during the literature search. The question is: What is known about the user experience design, co-design, and its evaluation for older adults using transportation-planning e-tools to move around in the community? This scoping review followed the PCC framework: (P) older adults, (C) user experience design, co-design, and usability evaluation, and (C) transportation-planning e-tools.

This stage consisted of searching scientific literature published in English from January 2002 to October 2022, with an updated search conducted on October 3, 2023. The search was performed across 7 databases: MEDLINE (PubMed, NCBI), AgeLine (EBSCOhost), CINAHL Plus with Full Text (EBSCOhost), SCOPUS (Elsevier), ProQuest Dissertations and Theses (ProQuest), IEEE Xplore (IEEE Xplore Digital Library), and TRID (Transportation Research Board).

Databases and keywords were selected and confirmed during a multi-step process. First, the keywords and databases were selected by two of the authors (SBG and VP). Then, an experienced librarian (FL) reviewed and refined them, ensuring that the selected terms and databases were relevant to the research question. As part of the search strategy confirmation, FL provided feedback aligned with the PRESS 2015 Guidelines [24], offering expert guidance on refining keywords, optimizing Boolean operators, and using controlled vocabulary where available. These adjustments helped ensure both the accuracy and comprehensiveness of the search. Some decisions were made to retrieve the largest number of relevant sources. During the pretesting of the research strategy, incorporating transportation-related keywords alongside other search terms significantly reduced the number of relevant studies. To address this issue, the librarian recommended removing these keywords and adding the TRID (Transportation Research International Documentation) and IEEE Xplore databases. This adjustment ensured a more comprehensive search and improved the scope of the review. Finally, the keywords and databases were confirmed by a senior researcher (HP), an experienced professor in the field of user experience. The full search strategies, including controlled vocabulary and keywords, are detailed in Table 1. To ensure comprehensive coverage, we first identified controlled vocabulary terms from each database’s thesaurus (eg, MeSH in PubMed, CINAHL Headings, and IEEE Xplore’s indexing terms). Based on these terms, we then created a structured list of keywords for each concept to capture both indexed and natural variations of relevant terms.

The search results were exported into Zotero (Corporation for Digital Scholarship) for reference management. Duplicate records were initially removed using Zotero’s automated deduplication feature, followed by a manual review by the first author (SBG) to identify and eliminate any remaining duplicates.

The inclusion and exclusion criteria were established before the study commenced and applied during the screening process (SBG, VP, and HP). Sources were included if they were (1) focused on developing or evaluating e-tools, and (2) discussed e-tool usability or user experience. Sources were excluded if they did not apply to the target population (older adults). To evaluate a larger range of studies, articles whose target group was 50 years or older were considered. Some studies define ’older adults’ as individuals aged 65 years and above, while others include individuals aged 50 years and older, especially in the context of research related to aging and technology use [25]. Considering individuals aged 50 years and older as “older adults” helped to retrieve a broader set of articles, particularly those focusing on promoting the use of e-tools for the aging population. This approach ensured that relevant studies addressing the needs of both younger and older segments of the aging population were included, capturing a more comprehensive view of user experience with transportation-planning e-tools. The first author (SBG) screened all identified sources by title and abstract, followed by a full-text review to assess their eligibility. To mitigate the risk of bias, 20% of the study selection process was independently reviewed and confirmed by co-authors (VP and HP).

A data charting form was developed by SBG and validated by VP, using a Microsoft Excel software grid that included source characteristics (authors, year of publication, title of the article, source of article, country, and context of the studies), the purpose of the studies (objectives and study orientation), and mapping of the methodology and evaluation of user experience (design approach, setting, type of data collection and analysis, type of usability evaluation, and sample size).

Both descriptive-analytical method and thematic analysis [26] were used to analyze all categories of data (characteristics of sources, purpose of the studies, and the reflection of the methodology and evaluation). Results were discussed, analyzed, and combined to identify the knowledge gap. Table 2 shows the list of selected articles.

Overall, 1905 studies were identified through the databases. The record after duplicate elimination was 1854. In total, 68 sources were retained after screening for title and abstract. Finally, since 28 records did not meet the mentioned inclusion and exclusion criteria, 40 sources were included in this review (Figure 1; Checklist 1).

Out of a total of 40 studies, 4 studies [27,52,57,58] were published during the first decade of the scope (2002‐2012) (10%), while 36 studies [14,25,28-51,53-56,59-64] were published after 2012 (90%). These studies were conducted across different continents, with 14 (35%) in Europe [14,27-29,32,36,37,39,42,45,53,55,57,62], 10 (25%) in Asia [31,33,38,40,44,46,47,52,56,60], 12 (30%) in North America [25,30,35,43,49-51,54,58,59,63,64], and 4 (10%) in South America [34,41,48,61]. The majority of the sources (29 studies) were peer-reviewed articles, representing 72.5% of the total [14,25,30,32,33,35-45,48-51,54,55,57,58,60-64], while the remaining 11 studies were conference articles (27.5%) [27-29,31,34,46,47,52,53,56,59].

Most contexts of the identified studies were related to health [14,28,32,34,35,37-39,41-44,49-51,54,60,62,64]. The other identified study contexts included tourism [27,57], shopping [31], daily planning [25], learning [45], social and physical well-being [47], physical activity [48], service provider [29], communication [30,40,61], nutrition [33,36], social network [53], entertainment [55], and weather [63]. In total, 3 articles did not specify the context of the study [46,58,59]. In total, 2 studies aimed to develop an e-tool and evaluate user experience in transportation [52,56].

The purpose of the selected articles was categorized into three groups: (1) documenting or extracting usability design principles specified to older adults, (2) evaluating user experience, and (3) developing or redesigning an e-tool for older adults. Out of the 40 articles, only 1 (2.5%) followed all 3 objectives [57]. In total, 12 (30%) articles [25,27,29-31,33,46,51,55,56,58,59] focused on evaluating user experience, while 19 (47.5%) articles [28,34,35,37,39,40,42,43,45,47,49,50,53,54,60-64] concentrated on both evaluating user experience and developing or redesigning an e-tool. The remaining 8 (20%) articles [14,32,36,38,41,44,48,52] only focused on developing or redesigning an e-tool. Evaluating user experience had the highest rate among all the studies, representing 80% of the total (32 studies) [25,27-31,33-35,37,39,40,42,43,45-47,49-51,53-64].

The number of participants varied, based on the purpose of the evaluation (ranging from 3 to 168). In the studies with a participatory or co-design approach (8 studies), the average sample size was 10, ranging from 3 to 22.

Most of the studies focused on developing eHealth, and only 2 articles [52,56] were related to transportation. The first one [52] was about the usability evaluation of an existing travel planning website via a user-centered design approach and did not concentrate on developing the website, while the other one [56] concentrated on evaluating the user experience of existing rail terminal interfaces for older people without using any design approach. The first one was conducted in a laboratory setting with 3 older adults via various qualitative methods, while the second one was conducted in a real-life setting with 5 older adults and 5 adults via a combination of both qualitative and quantitative methods. Although 1 of these 2 articles was performed in a real-life setting, this study aimed to evaluate older adults’ experience using existing services and did not concentrate on developing a transportation planning age-friendly e-tool.

This scoping review aimed to identify knowledge gaps regarding the user experience design of older adults in using transportation planning e-tools. Our study reveals that e-tools designed for older adults have grown dramatically in recent years in health-related fields, while only 2 studies were related to transportation. Despite the large number of e-tools that have been developed to support transportation planning [70], documenting the user experience is rarely considered. This lack of focus may explain why it remains challenging for many older adults to use these e-tools effectively while planning their travels and finding their way from one place to another. For example, real-time travel information, as a crucial aspect of travel planning [71], is expected to significantly impact the user experience of older adults, by reducing the anxiety of getting lost [72], protect them from the weather traffic congestion [73,74] and enhance the use of modes of transportation that are tailored to their needs and preferences [75]. Statistics Canada [76] reported that only 54% of older adults have a smartphone for personal use, many of whom rarely use its various functions, which creates a gap between the intended goal of transportation planning e-tools and their current use. The lack of studies aiming to document older adults’ experience in using transportation planning e-tools might thus affect their accessibility in terms of content and functionality. In this context, Subasi et al [77] argue that developing a system that is not only universally accessible but that also meets the specific expectations of older adults will optimize their usage of the digital system.

This review also revealed the lack of studies concentrating on developing transportation planning e-tools using participatory design. This result might be explained by the challenges related to this design approach, such as substantial time, resources, and institutional commitment [78]. In participatory design, designers try to learn the realities of users’ situations while the users strive to articulate their desired aims and learn the appropriate technological means to acquire them [20]. Although it seems that participatory design is an approach to the user-centered design [79], it is actually a shift in attitude from designing “for” users (user-centered design) to designing “by” users (participatory design) [80]. To address the challenges of participatory design, it would be good to understand the optimal methods and timing for involving users in the study process. Providing concrete deliverables and regular updates [81] could motivate participants by demonstrating the tangible results of their contributions to the development of transportation planning e-tools. Additionally, establishing a welcoming and enjoyable atmosphere at the beginning of co-designed sessions, such as icebreaking [9], can help participants feel comfortable and build trust with the researchers. Simplifying some consultation sessions into questionnaires or virtual sessions could lessen the burden of in-person meetings for both older adults and the research team, particularly during winter. This strategy would also facilitate frequent and balanced engagement with older adults while reducing expenses [82].

Although the aim of a considerable number of studies was to evaluate the experience of older adults using existing or newly developed e-tools, only 1 [57] considered not only evaluating user experience and redesigning an e-tool but also documenting usability design principles. It should be noted that developing usability design principles and guidelines for age-friendly e-tools is crucial due to variations in older adults’ design characteristics [83]. Some user-centered methods, such as persona [84], might help to consider the needs and preferences of a wide range of older adults in developing age-friendly e-tools. More specifically, persona is used to identify user expectations through the definition of personality characteristics and specific personal details [84]. According to Cooper [85], the aim of persona is to have a comprehensive and global view of the target population to know for whom the product is not intended, and its approach is concentrating on “specific or canonical users” [84]. As none of the reviewed studies mentioned the use of persona, it would be interesting for future studies to explore how this method could help classify older adults with, for example, varying levels of digital literacy, diverse mobility profiles, and different travel planning habits. This could help identify variations in older adults’ design characteristics and aid in the development of usability design principles.

Based on our results, combining formative (expert-based) and summative (user-based) usability evaluation using a mixed-method and providing the intersectoral participation of different disciplines might help to perform a comprehensive evaluation of the transportation planning e-tools for older adults. Indeed, most of the sources reviewed (77.5%) used both qualitative and quantitative methods for data collection and analysis, which helps to gain a detailed understanding of the needs and preferences of older adults. As argued by Creswell and Plano Clark [86], using a mixed method could provide a deeper understanding of older adults’ expectations in travel planning via transportation planning e-tools that would help to further improve knowledge in the production of guidelines and—accordingly—develop useful e-tools. Furthermore, most of the articles conducted in standardized situations used summative usability evaluation (user-based testing), highlighting the urgent need to capture the experience of older adults, more specifically in real-life settings, to help design products as close to actual usage as possible [87]. However, conducting a summative usability evaluation in a real-life context is challenging, due to its resource-intensive and time-consuming nature, which makes it costly. To address these challenges effectively, it would be good to adopt a participatory design approach involving a minimum of 5 participants. These participants should encompass diverse mobility profiles, digital knowledge, and travel planning habits, representing the targeted end-users to address 80% of usability problems, as proposed by Nielsen [65].

This study identified knowledge gaps regarding the design user experience of older adults when using transportation planning e-tools. However, it has certain limitations. Although the data selection and extraction processes were confirmed by co-authors, study screening was performed by the first author. It is possible that some articles were not retrieved due to the selected keywords and lack of consideration for gray literature. Moreover, we did not use the methodology suggested by Levac et al [88], that includes a consultation step. This step would be practical in transferring development knowledge for e-tools for a broad spectrum of older adults through different disciplines such as gerontology, web developing, and design. Finally, although we did not systematically account for all plural forms, alternative spellings, or flexible word order, the use of controlled vocabulary (eg, MeSH terms) and keyword variations helped maximize the retrieval of relevant literature, while the librarian’s review ensured the rigor of the search strategy and adherence to best practices in systematic reviews.

Supporting the mobility of older adults should be a priority in developing a transportation-related e-tool. According to this review, there are no studies aimed at specifically improving the mobility experience of older adults using an age-friendly transportation planning e-tool in a real-life context. Therefore, it is necessary to fill this gap by using a participatory approach (co-design) to better understand the needs of older adults in a real context to create age-friendly design principles and guidelines in the development of a transportation planning e-tool. This will not only improve their usability experience when planning a trip using a transportation planning e-tool but also strengthen their social participation.