Contextual factors influencing the urban mobility infrastructure interventions and policies for older adults in low- and middle-income countries: a realist review

Globally, there is a rapid growth in the aging population with a simultaneous rise in the number of older adults living in cities. It is projected that between 2015 and 2050, the population of older adults above 60 years will increase from 12% to nearly 22% [1], intensifying the demand for better quality services in every sector, including urban transport. A majority of the older adults in low- and middle-income countries live in cities that are not designed according to their needs, and for them accessing essential services such as healthcare, employment and social life may involve commuting in unsafe, irregular, and expensive transport services [2‐5]. The transportation needs of older adults may vary depending on factors such as employment status, possession of driver’s license, leisure activities etc. If mobility is hindered, it begins to affect their well-being [6]. The sustainable development goals, consisting of 17 goals, are a plan of action which is interlinked to achieve a sustainable future for everyone across the globe by 2030. Among them, sustainable development goals 3 and 11 are of relevance for this review. The third sustainable development goal lays emphasis on ensuring healthy lives and promoting well-being for everyone, including older adults [7]. In this context, safe and affordable mobility infrastructures are key lifelines for older adults to reduce transport-related social exclusion and improve access to essential services required for maintaining a better quality of life [8‐10]. Available evidence also underscored the linkages between improved transport infrastructure and welfare outcomes of older adults. For instance, interventions such as improving transport infrastructure and urban regeneration showed an improvement in mental health and quality of life outcomes [11, 12].

Making cities sustainable by investing in public transport through urban planning and management is a part of the sustainable development goal 11 [7]. However, in low- and middle-income countries, which according to the World Bank refers to countries classified under low-income, lower-middle-income, and upper-middle-income economies [13], the urban residents, especially older adults, face difficulties in accessing transportation that limits their contributions to the society and the ability to lead productive lives [3, 14]. In recent years, to cope with rapid urbanisation, a few initiatives towards improving access and safety in urban transport infrastructure have been undertaken for older adults in different low- and middle-income countries [15‐17]. Despite efforts from national and international agencies to address the needs of older adults concerning public transportation (for e.g., bus rapid transit systems, bus corridors with priority lanes, improvement in public transport and non-motorised transport services) inequalities faced by older adults while accessing urban transport infrastructure are noticeable across regions [14, 18, 19]. Subsidised fare made public transport affordable to the most vulnerable population in Latin American countries such as Columbia and Chile [20]. Similar interventions can be adapted in other low- and middle-income countries to make public transport accessible to older adults irrespective of their income levels.

It is evident that in low- and middle-income countries, implementation of interventions is limited by context-specific social, economic, and political barriers [21, 22]. In this light, comprehensive scientific information on the underlying mechanisms of why an intervention was successful or not to ensure equitable access for older adults to mobility infrastructure remained unexplored. A deeper understanding of intervention mechanisms in the context of low- and middle-income countries can be provided through a theory-driven and interpretive approach, i.e., a realist review given by Pawson and colleagues (2005) [23]. Although this method has not been used previously to synthesise evidence in the area of transportation interventions, it has the potential to provide comprehensive evidence to guide policy and practice in this area of research.

A realist review encapsulates existing theory, evidence from previous research and stakeholder consultations in understanding the issues around the implementation of interventions with a contextual lens. Realist reviews have been used in understanding complex interventions related to health, housing, education etc. [23, 24]. Therefore, this realist review could help us identify the gaps in researched transportation interventions and the generated findings could guide policymakers to design projects or re-design the existing mobility services. The following research questions will be addressed through this review 1) what are the urban mobility infrastructure interventions and policies/policy measures in low- and middle-income countries to improve the accessibility and safety of older adults? (2) How do contextual factors influence the success or failure of such interventions and policies/policy measures?

For this review, we apply the following definitions:

The protocol for this review was registered with the PROSPERO database (registration number: CRD42020168020). The realistic review involved seven phases explained below.

A total of 36 studies met the inclusion criteria, of which 16 focused on urban mobility infrastructure interventions, and 20 were related to transport policy/ policy measures. The study selection process is shown in Fig. 2. Evidence was obtained from literature reviews (n = 18), systematic reviews (n = 3), reports (n = 8), survey (n = 2), case studies (n = 2), randomised controlled trial (n = 1), mixed methods (n = 1), and qualitative content analysis (n = 1). Evidence came from 5 low-income countries, 18 lower-middle-income countries, and 13 upper-middle-income countries. The characteristics of included studies are given in detail in table 1a and 1b (additional file 3).

This realist review summarised the findings of 36 articles in 36 low- and middle-income countries on various urban transport infrastructure interventions, why certain interventions and policy measures were successful or not successful. It is important to identify and make note of failures in the current interventions and policy measures, which restrain further progress. At the same time understanding the reasons for successful interventions will help policymakers and transport planners design interventions according to the context. Sustainable transport infrastructure, which promotes social inclusion and safety will eventually have an impact on the well-being of older adults [67, 68]. Some of the key observations from our review are discussed below.

Behaviour change communication interventions are affordable and have a better prospect at long term sustainability. It has been used effectively in various public health and transport interventions to obtain desired outcomes [69‐73]. For example, educational campaigns for users through information kiosks in Brisbane and using informative models of the stations and vehicles in Peru before implementation of the project resulted in better public acceptance of public transport [43]. In the context of this review, it was identified that educational interventions alongside an improvement in transport infrastructure helped in better acceptance of public transport followed by a shift from private to public and motorised to non-motorised transport. It was observed that an increase in public transport users simultaneously increased active transportation to access the public transport transit stations [62, 74]. Evidence from developed countries showed that an improvement in transport infrastructure had subsequently increased walking for transport, which helped in promoting physical activity for older adults resulting in their better well-being [75‐79]. Likewise, empowering older adults to voice their concerns helped reduce road accidents and thus accident-related injuries and fatalities due to rash driving. Additionally, sensitizing the public and transport personnel helped them to be more considerate towards older people, further improving social inclusion of older adults in public transport. However, considering the fact that illiteracy was a barrier to behaviour change communication interventions, more images rather than text messages could be used while communicating information.

Inadequate funding in various low- and middle-income countries acted as a barrier to the implementation of inclusive transportation interventions. In such situations, it is beneficial to identify low-cost solutions to provide sustainable transport options. Public–private partnership in transport interventions in China where multiple bus agencies were involved in bus rapid transit was found to be cost-effective. Similarly, public–private partnership initiatives in a few cities of developing countries like Latin America and Asia have shown significant benefits in urban public transport, especially with respect to developing socially inclusive communities [80, 81]. However, a few challenges with respect to public and private agencies were seen in Maharashtra, India, where public–private partnership initiatives have been taken up [82]. Therefore, we recommend that contextual factors at systemic/ organization level should be considered before taking up public private partnership initiatives in other low- and middle-income countries [83].

The review brought to light that involvement of stakeholders during the projects’ design phase was lacking. A case study from the city of Indore, India reported that the importance given to public outreach by the implementing authority contributed to the success of bus rapid transit (iBus) in Indore [14]. Hence, it is recommended that public consultation should be given importance before planning for projects. Another important issue, which was highlighted during the stakeholder consultation was the lack of proper evaluation after the implementation of the project. New projects were planned even before evaluating the previous project. Though bus rapid transit is a low-cost project, suitable for medium-sized cities, there is a [perhaps wrong] notion by the authorities that it is not feasible for countries like India and Bangladesh. This suggests the importance of investing in low-cost solutions like bus rapid transit and non-motorised transport infrastructure. Hence, a detailed evaluation of implemented projects before drawing conclusions is strongly recommended for all transport infrastructure interventions.

It was evident from the review as well as stakeholder consultations that policy initiatives were available for older adults, but the implementation of such policies are not up to the mark. Therefore, many interventions to improve infrastructure are not sensitive to the needs of older adults. There are universal accessibility guidelines for all vulnerable groups, which may miss out few minor challenges faced by older adults. According to the age-friendly cities guidelines, transportation is one of the important domains affecting the well-being of older adults [84]. Research emphasising the importance of transport policies and health outcomes has been conducted, but a lack of commitment from the government in engaging the community to design and implement interventions was observed in a few low- and middle-income countries. A few stakeholders in our research highlighted the importance of gender-specific targeted interventions for older women. Older women felt unsafe while travelling on the public transport and walking alone after it was dark due to thefts, inadequate street lighting, lonely streets, and inappropriate behaviour of men on the bus, for example sitting in the seats allotted for women or standing closer to where women were sitting [85, 86]. Additionally, they faced challenges with the poorly maintained infrastructure of buses as well as walking pathways due to frailty. It is reported that older women are frailer and have much higher incidents of falls compared to older men [87‐89]. However, the review failed to identify such interventions in low- and middle-income countries specifically designed for older women, thus suggesting the need to focus on transport interventions for older women. Policymakers could use recommendations from available research, to design transport infrastructure with a focus on older women.

An important implication for research is that there is a need of an implementation and evaluation plan for the interventions and policy measures in place. More importantly, local authors should use the evidence from previous interventions/programs to design and implement the next one, or else the taxpayer’s money will not be well recognised. To make the older adults feel included in a society it is important to re-think transportation policies and re-design the existing transport infrastructure to suit their mobility needs. An integrated approach is necessary in building age-friendly communities, which will improve the overall well-being of older adults. Based on our findings, behaviour change communication approach was effective to increase awareness among individuals and improving the safety of users by reduction of road traffic injuries. Efforts to collaborate with various stakeholders such as local administration, schools, community members and non-government organizations are important to make the behaviour change communication approach effective. Improving public transport and non-motorised transport infrastructure led to a shift from private to public mode of transport, which has a long-term impact on the well-being of individuals. Therefore, ensuring good governance, coordination between departments, skilled personnel, adequate funding for project sustainability, and stakeholder consultation before planning any intervention will result in developing sustainable, cost effective, and socially inclusive urban transport infrastructure.