Research On The Interaction Between Road Network And Urban Expansion

Nowadays,urban land expansion has been a global trend of urban development.As the largest developing country in the world,China has increased its construction land by6 times and much larger than the same period of urbanization growth ratio in 1981-2015.Rapid urban expansion causes a sharp drop in arable land,environmental damage,traffic congestion and other issues.Road network is the main driving force of urban expansion,and has a close relationship with urban expansion.Therefore,the study of the interaction relationship and the quantitative relationship between them is a new perspective to guide the sustainable development of the city.In this study,we analyzed the interaction between urban expansion and road network through theoretical research,and carried out empirical research on urban expansion and road network at national and urban scale.Secondly,based on GIS and remote sensing,this paper analyzed the spatial relationship between urban expansion and road network in Beijing,New York,London and Chicago from 1985 to 2015,and then established road network-urban expansion model to calculate the turning points of urban expansion using regression analysis.Thirdly,the Urban Expansion Steady-State Index(UESI)was proposed and calculated for New York,London,Tokyo,Paris and other 13 world-class cities.Finally,under the multiple scenarios set,Logistic-CA-Markov model was used to measure the state of urban expansion in Beijing in 2025.The main conclusions included:(1)there was an interactive relationship between road network and urban expansion.Road network had a driving effect on urban expansion,and when the urban expansion occurs,road network optimized by urban expansion led to the new round of urban expansion;(2)there was a spatial quantitative relationship between road network density and urban expansion.This relationship was manifested as "inverted U",that was,urban expansion speed increased first and then decreased with the increase of road network density.The turning point values of Beijing,New York,London and Chicago were 3.3,11.84,16.86 and 21.40 km / km2 respectively.The turning point value of Beijing was much lower than the values in New York,London,Chicago,while lower than 5.1 km / km2 in Sao Paulo;(3)Urban Expansion Steady-state Index(UESI)could effectively measure the trend of urban expansion.When UESI ? 0.30,the state for urban expansion would achieve relative stability.New York,London,Tokyo and other cities' UESI values were greater than or close to 0.30,andBeijing,Sao Paulo's UESI values were less than 0.20;(4)in economic development scenarios(EDS),urban planning scenarios(UPS),ecological protection scenarios(EPS),the corresponding values of the turning point in Beijing would be 4.1,4.8 and 5.2 km /km2 in 2025.Taking the urban expansion threshold in 1985-2015,UESIEDS,UESIUPS,UESIEPS were 0.22,0.25 and 0.28,respectively.Vigorously promoting the planning guidance,intensive land use and ecological red line was conducive to achieve a substantial increase in steady state for Beijing in 2025.The results on the relationship between road network and urban expansion is helpful to scientifically understand the induction and guiding role of road network,optimize the investment of urban infrastructure and clarity the urban expansion stage,and provide references for urban planning,urban development and management decision.