The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibratio...The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibrations of traffic, and we listed successive scientific confirmations to indicate the rotation of the planet in a regular movement around its axis once every 24 hours, and it is running in another second movement around the sun once every 365¼ days, so are they only two movements, no more?! Is it possible for him to run at a regular speed in an additional direction?展开更多
Automated vehicles(AVs)hold the potential to reduce road accidents,mitigate traffic congestion,and improve travel experience.However,the possible countervailing impacts from the changes in underserved populations’veh...Automated vehicles(AVs)hold the potential to reduce road accidents,mitigate traffic congestion,and improve travel experience.However,the possible countervailing impacts from the changes in underserved populations’vehicle travel demand tend to be overlooked.To determine the vehicle travel demand changes that resulted from underserved populations aged between 6 and 80,this paper explores the latent effect of AVs on vehicle kilometers traveled(VKT)in a fully AV environment using person trip survey data from the cities of Sanya,Shijiazhuang,and Shenzhen in China.This paper uses the natural decline hypothesis of travel demand and proposes a regression model to investigate the difference among the cities’latent vehicle travel demand.Results show that the average VKT of the overall population in Sanya,Shijiazhuang,and Shenzhen increased by 33.4%,47.0%,and46.8%,respectively.The analysis of the regression model confirms that the current travel behavior of individuals can affect the degree of increase in their average VKT.Integrating AVs into public transport,increasing the acceptance of automated shared mobility options,transforming road space use type,and prototyping AV designs with various features and needs are potential methods to cope with the countervailing impacts.The total VKT of the overall population increased by approximately 10%-25%depending on the city.The conclusions of this paper provide informative insights into the evaluation of VKT for underserved populations and contribute to the deployment of AVs to address equity and inclusion issues.展开更多
To develop an equation between discrete degree of speed and traffic accident on freeway in China and give reasonable suggestions of speed management, the relation model was established between speed standard deviation...To develop an equation between discrete degree of speed and traffic accident on freeway in China and give reasonable suggestions of speed management, the relation model was established between speed standard deviation and accident rate per 100,000,000 vehicle kilometers by regression analysis. The model shows that the more discrete is the speed distribution, the higher is the accident rate, which provides theoretical gist for speed limit on freeway. It is suggested that speed limit should be set according to 85th percentile speed obtained by the relationship between 85th percentile speed and RCCs (curvature change rate of single circular curve), and different speed limits should be set for cars and trucks. Through analyzing spot speed data of eight freeways in China, regression models were established between 85th percentile speed and RCCs and 15th percentile speed and RCCs. Reasonable speed limit suggestion values are put forward through these models.展开更多
It didn’t take long to travel the seven kilometers from Kashgar city center to the renowned“Folk Instrument Village.”At the center of the village square is a three-meter-tall colored sculpture of Gijak(fiddle).The ...It didn’t take long to travel the seven kilometers from Kashgar city center to the renowned“Folk Instrument Village.”At the center of the village square is a three-meter-tall colored sculpture of Gijak(fiddle).The main gate is a Uygur-style structure supported by 12 columns symbolizing the 12 Muqam(the 12-section classic music of the Uygurs).A variety of folk instruments are painted on the walls on both sides.展开更多
文摘The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibrations of traffic, and we listed successive scientific confirmations to indicate the rotation of the planet in a regular movement around its axis once every 24 hours, and it is running in another second movement around the sun once every 365¼ days, so are they only two movements, no more?! Is it possible for him to run at a regular speed in an additional direction?
基金supported by the National Key Research and Development Program of China(2019YFB1600100)the Tsinghua University-Toyota Research Center Project(TT2019-05)National Natural Science Foundation of China(52302383)。
文摘Automated vehicles(AVs)hold the potential to reduce road accidents,mitigate traffic congestion,and improve travel experience.However,the possible countervailing impacts from the changes in underserved populations’vehicle travel demand tend to be overlooked.To determine the vehicle travel demand changes that resulted from underserved populations aged between 6 and 80,this paper explores the latent effect of AVs on vehicle kilometers traveled(VKT)in a fully AV environment using person trip survey data from the cities of Sanya,Shijiazhuang,and Shenzhen in China.This paper uses the natural decline hypothesis of travel demand and proposes a regression model to investigate the difference among the cities’latent vehicle travel demand.Results show that the average VKT of the overall population in Sanya,Shijiazhuang,and Shenzhen increased by 33.4%,47.0%,and46.8%,respectively.The analysis of the regression model confirms that the current travel behavior of individuals can affect the degree of increase in their average VKT.Integrating AVs into public transport,increasing the acceptance of automated shared mobility options,transforming road space use type,and prototyping AV designs with various features and needs are potential methods to cope with the countervailing impacts.The total VKT of the overall population increased by approximately 10%-25%depending on the city.The conclusions of this paper provide informative insights into the evaluation of VKT for underserved populations and contribute to the deployment of AVs to address equity and inclusion issues.
基金Special Research Fund for Doctoral Program of Higher Education of China(Grant No.20030213030)
文摘To develop an equation between discrete degree of speed and traffic accident on freeway in China and give reasonable suggestions of speed management, the relation model was established between speed standard deviation and accident rate per 100,000,000 vehicle kilometers by regression analysis. The model shows that the more discrete is the speed distribution, the higher is the accident rate, which provides theoretical gist for speed limit on freeway. It is suggested that speed limit should be set according to 85th percentile speed obtained by the relationship between 85th percentile speed and RCCs (curvature change rate of single circular curve), and different speed limits should be set for cars and trucks. Through analyzing spot speed data of eight freeways in China, regression models were established between 85th percentile speed and RCCs and 15th percentile speed and RCCs. Reasonable speed limit suggestion values are put forward through these models.
文摘It didn’t take long to travel the seven kilometers from Kashgar city center to the renowned“Folk Instrument Village.”At the center of the village square is a three-meter-tall colored sculpture of Gijak(fiddle).The main gate is a Uygur-style structure supported by 12 columns symbolizing the 12 Muqam(the 12-section classic music of the Uygurs).A variety of folk instruments are painted on the walls on both sides.
