Understanding Public Transport Accessibility across Economic, Physical, Organizational and Temporal Realms

It is proposed to “revisit” the concept of Public Transportation Accessibility using the categorisation of Cass, Shove and Urry (2005) on the four dimensions of “access”, namely economical, physical, organisational and temporal (Monzón and López, 2020).

The economic dimension

This dimension deals with the required expenditure of financial resources to travel by different transport modes, such as costs of car ownership and use or cost of transit. For certain vulnerable low-income population groups – for example, the retired and unemployed or teenagers – the cost of transit may constitute an access constraint (Lucas, van Wee and Maat, 2016). In other cases, low-income population groups have higher transport expenditures than they can afford (Cascajo et al., 2018; Lucas et al., 2016), as in the case of population groups “forced into car ownership” given the lack of public transport options. Elsewhere, mostly in developing countries, unaffordable transport can exclude access to individual basic needs (Bocarejo and Oviedo, 2012).

Financial barriers can also act as a choice determinant between different alternatives, compelling people to make trade-offs between travel times and fares. In order to consider cost-related barriers, which risk leading to social exclusion, accessibility formulations should account for each individual’s transport affordability. This makes it possible to assess the degree of equity in accessibility across population groups with different income levels, as travel costs may act as a budgetary constraint for low-income groups in accessing their desired destinations (Monzón and López, 2020).

Only a few examples of accessibility formulations include transit fares. Bocarejo and Oviedo (2012) analyse this problem in their work done in the capital of a developing country (Bogotá, Colombia) for the case of the TransMilenio bus rapid transit (BRT) corridor. They used an accessibility formulation with an impedance function that included both travel time and percentage of income spent on transport, and found that the effects of equitable transit fares on accessibility to the labour market may be greater than the impact of policies to expand the public transport network.

El-Geneidy et al. (2016), who used an equity approach to assess job accessibility by transit in socially disadvantaged neighbourhoods in Montreal, Canada. This research proposes a set of new transit accessibility measures that incorporate both travel time and transit fares. The authors claim that these accessibility measures are more accurate and easier to communicate, as accessibility is converted into a monetised value.

Households make trade-offs between different expenditure items, including transport. In a situation of economic crisis, these trade-offs may be altered and transport expenditure may change as a result. This issue was the subject of research analysing changes in household transport expenditure during the 2008 – 2013 economic crisis in Spain (Cascajo et al., 2018). Transport was found to be among the items of household expenditure most affected by the crisis. The average amount spent on transport dropped to its lowest value in 2013, falling by 37% over six years.

The physical dimension

Physical constraints on access depend both on the design characteristics of the transport/land-use system, and on personal capabilities, which may imply impediments to accessibility. Transport projects aimed at minimising potential barrier effects include built environment measures, such as the design of transport infrastructure (e.g. interchanges), stops/stations designed for all (e.g. wheelchairs) or vehicles (e.g. low-floor bus). There are three interconnected aspects involved in providing good accessibility levels to public transport. The first affects all types of users, and consists of the adequate design of transport nodes and transfer facilities between modes, to save time and ensure hedonic transfer and waiting. It has physical and organisational elements that refer to the third dimension. The other two aspects are more relevant for disabled people and include the vehicle and station characteristics (Monzón and López, 2020).

The transport literature is slowly beginning to pay attention to accessibility aspects that focus on people with disabilities and the elderly (Banister and Bowling, 2004; Currie et al., 2010; Spinney, Scott and Newbold, 2009). This dimension is related to the policy objective of “accessibility for all”, which is an explicit goal of the European Accessibility Act of the European Commission (2015). Another closely related term is that of Universal Design (UD), which refers to “the design of transport systems in a way that they are accessible to all users, irrespective of the users’ abilities” (Odeck, Hagen and Fearnley, 2010). The appraisal of projects to remove physical barriers to access should obviously take into account the accessibility benefits for vulnerable groups such as the elderly, people with disabilities, children and the physically impaired. In addition (Odeck, Hagen and Fearnley, 2010), all transport users benefit from these projects through enhanced efficiency from reduced travel times on public transport.

The organisational dimension

These organisational aspects of access refer mainly to the frequency, reliability and punctuality of the transport service, but also include other measures such as the definition of bus routes, the quality of the travel experience, and the conditions in waiting and interchange locations. Some of the variables in the organisational dimension of access can be investigated within the scope of the assessment of the convenience of public transport. Convenience assessment includes (Wardman, 2014):

• access and egress time, in particular walking time at any stage of the journey
• waiting time, including time spent while transferring between services or modes
• being unable to travel at the desired time, covering service headway and displacement time
• having to transfer during a journey
• travel time variability and lack of reliability
• absence of good information or signage
• crowding.?

The task of incorporating these organisational dimensions into definitions of accessibility is complex, although necessary to assess the whole range of “user benefits”. Organisational issues also have an effect on the range of activities that can be carried out while travelling, which are also part of the utility of the trip (Ettema et al., 2010; Mokhtarian and Salomon, 2001). People do not value equally all travel time savings, so an additional ten minutes’ travel time standing on a crowded bus would not be valued the same as the same ten minutes seated in a modern train.

The factors defining an efficient urban transport interchange were investigated from two different perspectives: functional and psychological. They can be allocated to three groups: related to ease and speed, related to comfort and services, and finally factors affecting safety and security. These groups define the dual perception of the interchange as a transport node and as a place to wait and engage in activities. High values in these factors reduce subjective costs and generalised time when accessing public transport and transferring between modes (Monzón and López, 2020).

In other cases, organisational constraints may prevent some population groups from using the transport network, such as people who wish to spend their commute doing tasks that require being seated (Garcia-Martinez et al., 2018). The inclusion of these organisational features – largely overlooked in accessibility formulations – could be of great potential to capture additional accessibility benefits.

The temporal dimension

This dimension of accessibility depends on temporal availability, and relates to both trip duration and to time and frequency of services, which may act as a barrier for people with limited time resources. It is also important to include the need to “juggle” to carry out an individual’s or their family members’ various mobility-related activities, such as food shopping after work, picking up children from school, and arriving home by dinner time (Cass, Shove and Urry, 2005).

Mixed land-use and transport designs can help in this juggling challenge, combined with information and communication technologies (ICT) capable of providing real-time information to minimise waiting times or include multimodal alternatives in the choice options. Transport network nodes in particular can play an important role in this temporal access, as providers of opportunities to carry out daily activities (Monzón and López, 2020). This is mainly the case of urban transport interchanges, which are increasingly receiving attention as “places” (not merely “nodes”) in which activities can be carried out if they are strategically planned (Hernandez and Monzón, 2016; Hernandez, Monzón and de O?a, 2016).

Lluis Sanvicens, 2023

References

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