Developing an urban bikeability index for different types of cyclists as a tool to prioritise bicycle infrastructure investments
Introduction
Benefits of cycling to public health, the environment, and the economy have been well documented in the literature. Cycling improves physical and mental health of travellers, reduces vehicular emissions and travel times, and generates cost-savings (e.g., Brown et al., 2013, Frank and Engelke, 2001, Hatfield and Boufous, 2016, Khan et al., 2014, Lee et al., 2011, Litman and Spielberger, 2003, Osama et al., 2017, Rietveld, 2001). Due to the wide range of benefits it offers to individuals and the community, many governments around the world are promoting initiatives and policies to encourage cycling (Buehler and Dill, 2016, Hatfield and Boufous, 2016, Osama et al., 2017).
In recent decades, there has been an upsurge of interest in researching the nature and determinants of cycling trips, primarily discussing the role of built environment attributes. The built environment comprises urban design (design of the city and the physical elements within it), land use (distribution of activities across space), the transportation system (physical infrastructure as well as the level of service provided) and patterns of human activity within the physical environment (Handy, 2002). The built environment is usually characterised using five attributes (hereafter also factors and components), the so-called “5Ds” (density, diversity, design, destination accessibility, and distance to transit) coined by Cervero & Kockelman (1997) and extended by Ewing and Cervero, 2010, Ewing et al., 2009. Studies suggest that cycling trips are positively correlated with built environment attributes, such as bicycle-infrastructure, traffic safety, comfort and attractiveness, employment density, and land use mix (e.g., Buehler and Pucher, 2012, Dill and Carr, 2003, Griswold et al., 2011, Haynes and Andrzejewski, 2010, Landis et al., 2001, Moritz, 1998, Moudon et al., 2006, Nelson and Allen, 1997, Osama et al., 2017, Parkin et al., 2007, Piatkowski and Marshall, 2015, Pucher et al., 2010, Strauss and Miranda-Moreno, 2013). Thus, the design of urban spaces that are amenable to cycling is essential for developing cities which are sustainable in multi-dimensional terms.
Several metrics have been developed to assess built environment attributes from a cycling perspective. The most popular metrics in the literature are the Bicycle Level of Service (BLOS) and the Bikeability Index (BI). The BLOS for a route represents an evaluation of comfort, security, traffic safety and convenience perceived by a cyclist regarding the motorised traffic while he/she runs on roadway corridor (Ilie et al., 2016, Lowry et al., 2012). The BI refers to the ease of access to a desirable destination for bicycles as a transport mode. The BI metric evaluates an entire bicycle network in terms of ability, perceived comfort, and convenience to access important destinations (Lowry et al., 2012, Saghapour et al., 2017). Other measures to evaluate built environment characteristics from a cycling perspective are presented in Section 2.
Despite the existence of all these metrics, they are rarely considered within the cyclist infrastructure planning process. In some cities, bicycle infrastructure investments tend to be a deliberative process between planners, elected officials, and citizens. However, this is not the case for some cities in the Global South, especially small and medium-sized cities. In these cities, bicycle infrastructure planning processes tend to be weak. Then, the development of tools to predict cyclist demand accounting for the influence of built environment attributes could strengthen the planning process to make better investment decisions. Not incorporating such metrics and demand forecasting tools to support the poor planning processes of some cities could bring harmful effects.
For example, in Barranquilla (Colombia) like other cities in the Global South, the few bicycle lanes in the city are located in the highest income zones, which are closer to the highest job density areas compared to low-income zones. In addition, the bicycle infrastructure planning definitely did not consider the bicycle users’ needs and perceptions, causing negative side effects. The construction of bicycle lanes in Barranquilla has been politically motivated to promote the use of the bicycle for recreation purposes among wealthy inhabitants, dismissing that most of the regular cyclists in the city are low-income people, who live far away from their job and study opportunities. Thus, unfortunately the location of those bicycle lanes does not allow regular cyclists to use them and is the reason why these facilities look desolate most of the time. Most current cyclists in Barranquilla use the ring roads to access their job opportunities despite all the associated safety risks caused by the presence of mixed traffic and the absence of bicycle facilities. Therefore, a forecasting demand tool that incorporates built environment characteristics from a cycling perspective could help planners to prioritise which cyclist infrastructure investment provides better connectivity for all users and has the highest potential to be regularly used.
The idea of supplying demand for transport and not improving accessibility can be criticized because in many cities it has led to road expansion for cars (Bocarejo & Oviedo, 2012). The planning perspective that cities should plan for what they want (e.g. active travel, healthy cities), not for what they have (e.g. car monoculture), is basically at odds with the common economic goal of supplying existing demand. However, in the case of Barranquilla, and perhaps many other cities in the Global South, where bicycling already exists but is poorly supported, traditional supplying of demand can still be a valuable perspective. This perspective can be useful, especially when certain travellers experience travel conditions that may not be considered favourable in other contexts. However, they indeed use the least worst option when travel alternatives available for them are few, and the cities offer vast inequalities in the provision of transport services. Therefore, tools to provide good information about where to invest could help bridging inequality gaps and promoting the use of sustainable transport modes that are easily available for most inhabitants.
The contribution of this paper is twofold. Firstly, a BI is developed that takes into account particularities of the roads in cities of the Global South and the preferences, perceptions and socioeconomic characteristics of different types of bicycle users. Perceptions about the conditions of the infrastructure and the built environment could strongly impact the decision to travel by active modes (Larrañaga et al., 2016, Arellana et al., 2020), especially in Global South cities. Moreover and similarly to the walkability literature, transferring bikeability indexes developed in other contexts could be problematic because of the diversity concerning socioeconomics, users’ preferences, and perceptions about the built environment characteristics, which justifies the construction of local indexes (Arellana et al., 2020). Secondly, a tool is developed for decision-makers to prioritise investments in bicycle infrastructure, considering the estimated BI and expected cyclist flows (i.e., bicycle travel demand). The tool prioritises infrastructure investments according to their expected impacts on cyclist demand estimated by a direct demand model, which includes the BI as an explanatory variable. Developing such tool and incorporating it in the planning process could lead to an equity-focused prioritisation rather than an accessibility-focused prioritisation of bicycle infrastructure investments, which is particularly relevant in cities with great inequality, such as those of the Global South.
The remainder of this article is divided into four sections. Section 2 presents the literature review. Section 3 describes the methodology applied to construct the BI as well as the method to develop the tool to prioritise bicycle infrastructure investments. Section 4 describes the case-study area in Barranquilla, Colombia and presents the results obtained. Finally, Section 5 offers conclusions.
Section snippets
Literature review
This section reviews previous studies that developed and evaluated bikeability measures. We considered 53 papers published within the 1994–2020 period. The review discusses four aspects of bikeability literature. First, the geographical location of the studies. Second, the different bikeability measures, highlighting some of their characteristics. Considering these two aspects, geographical location and the bikeability measures, we developed the taxonomy presented in Table 1. Third, the
Methodology
The proposed methodology is structured into two stages that are addressed sequentially. Stage 1: Bikeability index construction; and Stage 2: Prioritisation tool of bicycle infrastructure investments.
Case study, results and discussion
This section describes the application of the methodology to the city of Barranquilla, Colombia. Barranquilla is the largest city of the Colombian Caribbean and has an average temperature of 28.4 °C (85°F) with high levels of relative humidity. Despite its size, and being the fourth most populous city in Colombia (1.228 million), it only has 14.5 km of bike paths and this bicycle infrastructure is mainly located in the northern part of the city, the highest income zone. Barranquilla is a city
Summary and conclusions
A new methodology was proposed for developing an urban bikeability index that addresses particularities of the roads in cities of the Global South and it can be segmented by type of cyclist. Different types of cyclists arise from combinations of socioeconomic status, frequency of bicycle use, and travel purpose. Our bikeability index is especially novel because it takes into account the socioeconomic characteristics of bicycle users and their preferences and perceptions regarding built
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