income disparities, as public capital investment tends
to be negatively correlated with income disparities in
the short run, but may be positively correlated in the
long run (Lu et al., 2022). Interregional public
transportation infrastructure may also widen the
urban-rural income disparity (Valenzuela-Levi,
2023). Others hold that the impact of transport
infrastructure on the rural-urban income disparity
may be characterized by significant threshold
nonlinearities, and that while improved transport
infrastructure promotes connectivity between rural
and urban areas and equalization of access to
resources, such improvements may not be sufficient
in the short term to fully reverse the lag in rural areas
(Ma et al., 2023). With regard to the mechanism of
transport infrastructure affecting the urban-rural
income disparity, previous literatures have focused on
the important role of labor mobility factors, such as
the proportion of the rural population, in the impact
of transport infrastructure on the rural-urban income
disparity (Ren and Zhang, 2013), suggesting that its
impact on rural labor mobility shows a dynamically
changing correlation (Sun, 2020).
Existing literature provides substantial references
for revealing the impact of transport infrastructure on
the urban-rural income disparity, but the conclusions
are mostly based on linear assumptions, with certain
deviations from the reality, lacking explanations of
the internal mechanisms, and the theoretical guidance
for promoting urban-rural coordination and common
prosperity needs to be deepened. Therefore, from the
perspective of urban-rural income disparity and based
on the nonlinear correlation hypothesis, we
empirically investigate the impact, mechanism and
nonlinear characteristics of transport infrastructure on
common prosperity by using Chinese provincial
panel data from 2001-2020. The conclusions provide
theoretical guidance and significant policy
implications for the construction of transportation
facilities to further promote common prosperity in the
new era.
2 THEORETICAL ANALYSIS
AND RESEARCH HYPOTHESIS
Compared with urban residents, rural residents have
less access to factors of production and resources in
terms of quantity and quality, as well as less efficient
use of resources, a situation that can be improved by
investing in transport infrastructure. Firstly, transport
infrastructure can directly provide employment
opportunities, and its construction and maintenance
periods generate a large demand for less technically
demanding labor, which enriches the income sources
of rural labor and increases their incomes (Ma et al.,
2023). Secondly, transport infrastructure can
effectively reduce production transaction costs,
smooth urban-rural trade routes, expand the spatial
scope of markets, and increase farmersβ revenue. It
can also improve the structure of industrial
development in rural areas, promote the development
of the non-agricultural economy, solve the problem
of employment for the impoverished (Ren and Zhang,
2013). Thirdly, transport infrastructure can promote
the economy of road diffusion industry, so that the
resources along that are exploited to a greater extent,
radiate and drive the development of the surrounding
areas (Sun, 2020), promote the integration of urban
and rural economy, and thus facilitate the common
prosperity.
According to the dual structure theory, the
existence of a sectoral wage disparity will make rural
laborers tend to move across sectors in order to earn
higher incomes, but high mobility costs will restrict
rural laborers from moving across urban and rural
areas in practice, so that they will continue to engage
in low-income jobs in rural areas, and the urban-rural
income disparity will still exist due to the obstruction
of labor mobility (Banerjee et al., 2020). Transport
infrastructure will enhance urban and rural
connectivity, reduce the cost of rural labor migrating,
and promote labor mobility. As the transportation
network is continuously improved and the cost of
urban-rural travel is increasingly reduced, rural
surplus labor will be transferred to the non-
agricultural sector on a larger scale, and as the degree
of urban-rural connectivity deepens, a large number
of farmers will return to their hometowns to find
employment and start their own businesses, thus
realizing the optimal allocation of a wider range of
labor resources, narrowing the gap between urban and
rural areas, and promoting common prosperity (Liu
and Zheng, 2013).
Transport infrastructure is inseparable from its
construction and use and therefore may have threshold
character. It means that transport infrastructure often
needs to reach a certain scale and size to play its
role (Chen et al., 2021). According to the theory of
matching transport supply and demand, when the
stock of transport infrastructure is lower than the
demand, high transportation costs will affect
production efficiency, impede the cross-regional
circulation of factors and limit economic
development. Non-equilibrium theory shows that
high-investment, long-cycle transport infrastructure
construction needs to be moderately ahead of social