An investigation of traffic density changes inside Wuhan during the COVID-19 epidemic with GF-2 time-series images

Abstract

In order to mitigate the spread of COVID-19, Wuhan was the first city to implement strict lockdown policy in 2020. Even though numerous researches have discussed the travel restriction between cities and provinces, few studies focus on the effect of transportation control inside the city due to the lack of the measurement and available data in Wuhan. Since the public transports have been shut down in the beginning of city lockdown, the change of traffic density is a good indicator to reflect the intracity population flow. Therefore, in this paper, we collected time-series high-resolution remote sensing images with the resolution of 1m acquired before, during and after Wuhan lockdown by GF-2 satellite. Vehicles on the road were extracted and counted for the statistics of traffic density to reflect the changes of human transmissions in the whole period of Wuhan lockdown. Open Street Map was used to obtain observation road surfaces, and a vehicle detection method combing morphology filter and deep learning was utilized to extract vehicles with the accuracy of 62.56%. According to the experimental results, the traffic density of Wuhan dropped with the percentage higher than 80%, and even higher than 90% on main roads during city lockdown; after lockdown lift, the traffic density recovered to the normal rate. Traffic density distributions also show the obvious reduction and increase throughout the whole study area. The significant reduction and recovery of traffic density indicates that the lockdown policy in Wuhan show effectiveness in controlling human transmission inside the city, and the city returned to normal after lockdown lift.

Exploring the effect of COVID-19 pandemic lockdowns on urban cooling: A tale of three cities

“…While the outbreak of COVID-19 pandemic and the subsequent lockdowns arising from it have had a major negative effect on the conditions of economy, the environmental components have been slightly relieved of the great anthropogenic activities pressures, such as vehicle traffic, heat generation and large emissions of various pollutants ( Mahato et al, 2020 ; X. Wu et al, 2020; Chen et al, 2021 , Firozjaei et al, 2021a , Wu et al, 2021a ). Some studies have examined the impact of COVID-19 pandemic lockdowns on urban environmental conditions.…”

Urban birds’ tolerance towards humans was largely unaffected by increased variation in human levels due to COVID-19 shutdowns

“…The COVID-19 shutdowns locked people at homes and reduced their mobility within cities (Geng et al . 2021; Wu et al . 2021; but see Venter et al .…”

“…The COVID-19 shutdowns locked people at homes and reduced their mobility within cities (Geng et al 2021;Wu et al 2021; but see Venter et al 2020b) and thus created a natural experimental condition which could have affected the tolerance of urban animals towards humans (usually quantified as flight initiation or escape distance) in three ways. First, the lack of or reduced human presence during shutdowns might result in decreased animal tolerance to humans and consequently increased escape distances because (a) some studies have reported that animal tolerance decreases on the gradient from heavily human-visited ("disturbed") sites to sites with low human activity (Webb & Blumstein 2005;Mikula 2014) and (b) escape distances of urban birds may also increase if less tolerant individuals and species colonise or at least increase their detectability in human-emptied landscapes (Manenti et al 2020;Gordo et al 2021).…”

Data analytics during pandemics: a transportation and location planning perspective

“… 2021 ; Wu et al. 2021 ) and to estimate the number of emergency ambulance dispatches during a state of emergency (Rashed et al. 2021 ).…”