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Characterizing the stocks, flows, and carbon impact of dockless sharing bikes in China

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Abstract

The booming dockless sharing bikes (DSBs) in China, as a new sharing economy business model, have attracted increasing public and academic attention after 2015. The impact of DSBs development on the stocks and flows of bikes and the resource and climate consequences of short-lived DSBs, however, remain poorly understood. In this study, we characterized the stocks and flows of both DSBs and regular private bikes in China from 1950 to 2020 and evaluated the carbon cost and benefit of booming DSBs. We found China's bike consumption and stock decreased slightly after a fast development from the late 1970s and then a peak in the mid-1990s, resulting in a relatively low ownership of approximately 0.3 unit per person and 70% of production being exported in recent years. Despite a temporal boost, the unsustainable development of DSBs may affect the bike industry in the long term, because of its skyrocketing market share (from less than 1% to 80%) and short lifetime. Nevertheless, DSBs development still leads to an overall climate gain in China, due to its higher stock efficiency and potentials to substitute more carbon intensive trips. We suggest an urgent need for more empirical studies on the use (e.g., substitution ratio for other transportation models) of DSBs in China and a necessity for better management of DSB development with efforts of all relevant stakeholders.

Introduction

Transportation contributes to around one-quarter of global energy-related greenhouse gas emissions (McCollum et al., 2018), and is thus widely regarded as a big roadblock to global climate change mitigation (Creutzig et al., 2015) and sustainability transition. Among various transportation modes, bikes are thought the most sustainable from environmental, societal, and economic perspectives (Pucher and Buehler, 2017). For example, the direct environmental impact (e.g., almost no impact in use) and indirect impact (e.g., for bike manufacturing and infrastructure) of bikes are much lower than other transportation modes (Rajé and Saffrey, 2016). Besides, they change the sedentary lifestyle and lead to significant health benefits (Buekers et al., 2015). Cycling promotion could also create significant economic benefits for the society and people due to the reduced travel time budget, motorized vehicle use, and infrastructure (Brey et al., 2017).

China, the country once known as a “kingdom of bicycles”, has witnessed the boom and bust cycles of bike development. Bikes were not introduced until the late 19th century in China as a complement to walking, rickshaw, and a sedan chair. They then gradually spread across the country from the 1950s to the 1990s (Rhoads, 2012), when the bike was regarded as one of the four most stylish home goods and became one of the main transportation tools in cities (Zhang et al., 2014). Since the late 1990s, however, bikes were gradually phased out in daily transportation in the motorization and urbanization process (Zhang et al., 2014). In 2015, a new generation of sharing bike program (SBP) with dockless sharing bikes (DSBs) appeared in China, which people can start to use after scanning a barcode with a smartphone and return anywhere (Gu et al., 2019). This innovation (known as one of China's “four great new inventions” in modern times (Chinadaily, 2017)) provided convenience to urban citizens as a solution to the “last mile” challenge (e.g., between home, workplace, and public transportation stations) and dragged some urban residents back to two-wheeler life. Consequently, these DSBs flooded the market quickly and the DSB input boomed in 2017 and surpassed the available sharing bikes elsewhere in the world in 2016 (Felix, 2018).

However, the concept and practice of sharing bikes are not new. The global history of SBPs can be dated back to over five decades ago and they can be categorized as four main models (Fig. 1). Starting from white bikes in Amsterdam in 1960 (SBP 1.0), it took about three decades to shift to coin-based sharing bikes in Copenhagen (SBP 2.0) and Information Technology (IT) based SBP 3.0, and then another two decades to SBP 4.0 in China (Chaoze, 2017; Shen et al., 2018). These dockless sharing bikes penetrated the market in Chinese cities quickly after 2015 and boomed in 2017. Such renaissance of bikes came with an immediate cost due to the flooding venture capital investment and lack of regulation. Oversupply of DSBs vastly outpaced demand, colonized city streets, and caused various problems such as road occupation, massive vandalized bikes and bike graveyard, and bankruptcy of many DSB firms (DeMaio, 2009; Peter, 2011; Shaheen et al., 2010; Shen et al., 2018), which call for an optimized approach for planning and management (Awasthi and Omrani, 2019; Sayyadi and Awasthi, 2018).

In parallel with SBP development, the past decade has seen an increasing amount of publications on SBPs and DSBs across the world (Si et al., 2019). Most of these studies focus on how socioeconomic, spatial, and behavioral factors such as bike accessibility (the distance between use and station) and availability (possibility to find a bike) (Kabra et al., 2018), customer characteristics (Guo et al., 2017; Ji et al., 2017), behaviors (Li et al., 2018) and travel patterns (Du and Cheng, 2018), and built environment (Zhang et al., 2017) could affect the adoption and use of sharing bikes (Efthymiou et al., 2013; Yang and Long, 2016). Since the spatial and temporal imbalance between demand (Gervini and Khanal, 2019; Zhou et al., 2018) and (re)distribution (Ho and Szeto, 2017; Li et al., 2016) of sharing bikes is identified as the key to successful SBP development, some researchers have used different repositioning technologies and models to optimize the station position and address congestion or starvation issues of IT-based SBP (Forma et al., 2015; Ghosh et al., 2017; Szeto and Shui, 2018). This is of particular importance for DSBs due to their flexibility without docking stations, so demand forecasting (Xu et al., 2018), static (Liu et al., 2018) and dynamic repositioning problems (Shui and Szeto, 2018), optimizing location (Sun et al., 2019) and optimizing transportation planning (Sayyadi and Awasthi, 2018) are the key focuses of DSBs research as well in the transportation literature.

As the immense public attention and media coverage on China's DSBs fever brings both the pros and cons of DSBs into the spotlight, their environmental benefit and impact became an important question (Standing et al., 2019), which this paper aims to contribute to as well. On the one hand, shifting more motorized trips to DSBs for “the last mile” could boost public transportation use (Zhang and Zhang, 2018) and help create environmental benefit (Gu et al., 2019; Zheng et al., 2019). For example, through an analysis based on big data, DSB use was found to save energy and decrease emissions (e.g., CO2 and NOx) in Shanghai (Zhang and Mi, 2018). On the other hand, the additional materials use, such as electronics in DSBs and especially the significant amounts of short-lived DSBs in the graveyard due to fierce market competition, could cause an extra impact on resource, waste, and environment. For example, some life cycle analysis (LCA) based studies reveal a higher environmental impact of DSBs than station-based SBP (Bonilla‐Alicea et al., 2019; Luo et al., 2019) and breakeven point of its environmental impact in Beijing was calculated as 1.7 years of DSBs use (Chen and Chen, 2018).

These abovementioned studies provide an initial assessment of the environmental impacts of DSB development for two sides of the same coin, but a few knowledge gaps remain.

  • First, previous studies on the development and impact of SBPs and DSBs often only cover a short period of time and are insufficient to reveal their impacts on the dynamics (stocks and flows) of the bike industry (including regular bikes) and patterns and efficiency of bike use.

  • Second, the resource and environmental implications of the significant amount of short-lived DSBs due to oversupply and fierce competition driven by venture capitals to capture the market share has not yet been quantitatively addressed in previous studies.

  • Third, the carbon impacts are usually discussed in static snapshots and on a functional unit using LCA, therefore they could not capture the dynamics of bike stocks and their aggregated effects.

Therefore, we aim to address these gaps in this study by tracking the stocks, flows, and use of both DSBs and regular bikes in China from 1950 to 2020, and further comparing the carbon cost in production, operation, and end-of-life management of DSBs and their carbon benefit in use as a substitution to other transportation modes. The impact of DSBs development on the bike industry and policy implications on DSBs management are consequently discussed.

Section snippets

Characterizing stocks and flows of regular bikes and DSBs

We used a dynamic material flow analysis (MFA) approach to simulate the evolution of in-use stocks and flows of bikes (both regular bikes and DSBs) from 1950 to 2020. To capture the role of DSBs in the background of bikes development, we have included both regular bikes and DSBs in this study. However, bikes that are not human-powered (e.g., motorized or electric bikes) and the small quantity of sharing bikes in old SBP models before 2015 were not included.

For development from 1950 to 2017

Historical patterns of bike and DSB development

Fig. 2(a) below shows that bike production and consumption remained at a low level before the 1970s in China but started to increase since its open and reform policy in the late 1970s. Annual bike production was around 77.8 million after 2000. Annual bike sales hovered around 37.6 million units from 1980 to 1995. After 1995, bikes were more considered as a barrier of urban transportation in a motorized vehicles dominating way of urbanization (Zhang et al., 2014), and thus China's domestic bike

Discussion

Bike-sharing is an innovative business model that in theory follows the sharing economy principle with lower material stock or consumption for the same (if not more) service (Mi and Coffman, 2019). But the DSB fever triggered by venture capital investment leads to fierce market competition and thus raises questions on its benefit and cost that are not straightforward to answer. We have provided the first overview, to our own knowledge, on the stocks and flows of bikes and the role of DSBs in

CRediT authorship contribution statement

Wu Chen: Conceptualization, Methodology, Software, Validation, Formal analysis, Writing - original draft. Qiance Liu: Validation, Formal analysis. Chao Zhang: Validation, Formal analysis. Zhifu Mi: Formal analysis, Writing - review & editing. Dajian Zhu: Formal analysis, Writing - review & editing. Gang Liu: Conceptualization, Methodology, Writing - original draft, Writing - review & editing, Supervision, Funding acquisition.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work is funded by the National Natural Science Foundation of China (71991484) and the China Scholarship Council (201708510095). We thank Yu Dou and Xiaodong Huang for valuable research assistance and Hao Qin from Mobike company for helpful discussion.

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