Road condition is an important variable to measure in order to decrease road and vehicle operating/maintenance costs, but also to increase ride comfort and traffic safety. By using the built-in vibration sensor in sma...Road condition is an important variable to measure in order to decrease road and vehicle operating/maintenance costs, but also to increase ride comfort and traffic safety. By using the built-in vibration sensor in smart phones, it is possible to collect road roughness data which can be an indicator of road condition up to a level of Class 2 or 3 in a simple and cost efficient way. Since data collection therefore is possible to be done more frequently, one can better monitor roughness changes over time. The continuous data collection can also give early warnings of changes and damage, enable new ways to work in the operational road maintenance management, and can serve as a guide for more accurate surveys for strategic asset management and pavement planning. Collected measurement data are wirelessly transferred by the operator when needed via a web service to an internet mapping server with spatial filtering functions. The measured data can be aggregated in preferred sections, as well as exported to other GlS （geographical information systems） or road management systems. Our conclusion is that measuring roads with smart phones can provide an efficient, scalable, and cost-effective way for road organizations to deliver road condition data.展开更多
This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network ev...This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network evaluation theories based on road "V/C". In addition, it proposes a set of theoretical and technical methods for the real-time evaluation of traffic flows for entire road networks, and for solving key technical issues, such as real-time data collection and processing in areas with no blind zones, the spatial-temporal dynamic analysis of road network traffic, and the calibration of key performance index thresholds. It also provides new technical tools for the strategic transportation planning and real-time diagnosis of road traffic. The new tools and methodology presented in this paper are validated using a case study in Beijing.展开更多
At present, it is usually used the method that elevating the height of embankment to design passages of freeway to avoid transverse traffic disturbance in plain areas of China. But when design low embankment, it is di...At present, it is usually used the method that elevating the height of embankment to design passages of freeway to avoid transverse traffic disturbance in plain areas of China. But when design low embankment, it is difficulty for drainage or setting passages and culverts. Hengshui to Darning freeway in Hebei provence （Heng-Da freeway） is one section of Dalian to Guangzhnu freeway. This paper analyzes the characteristic of climate, geology, hydrology and low water table, good permeability stratum soil and its little and mass rain fall and deep drinking water well in the plain areas of North China when design low embankment of Heng-Da freeway, puts forward the drainage methods of water collecting filtration system to solve the drainage problem of passages and culverts, aiming at the type and the measures of the pollution on the surface, the channel collection purification infiltration system of highway uses the single composite technology of aerobic and oxygen to digest - precipitation-absorption of artificial materials percolation of soil to deal with the pollution of the rain on the road （the composite technology use the vermiculite as the material of infiltration）, which be controlled in the drinking range of the water standard. It not only efficiently solved the problem of water collected in the channel, but also supplied the groundwater. It has reached the environment-friendly road construction purpose of the sustainable development of highway construction, ＂environment friendly＂ and ＂resource conservation＂.展开更多
The concept of connected vehicles is with great potentials for enhancing the road transportation systems in the future. To support the functions and applications under the connected vehicles frame, the estimation of d...The concept of connected vehicles is with great potentials for enhancing the road transportation systems in the future. To support the functions and applications under the connected vehicles frame, the estimation of dynamic states of the vehicles under the cooperative environments is a fundamental issue. By integrating multiple sensors, localization modules in OBUs(on-board units) require effective estimation solutions to cope with various operation conditions. Based on the filtering estimation framework for sensor fusion, an ensemble Kalman filter(En KF) is introduced to estimate the vehicle's state with observations from navigation satellites and neighborhood vehicles, and the original En KF solution is improved by using the cubature transformation to fulfill the requirements of the nonlinearity approximation capability, where the conventional ensemble analysis operation in En KF is modified to enhance the estimation performance without increasing the computational burden significantly. Simulation results from a nonlinear case and the cooperative vehicle localization scenario illustrate the capability of the proposed filter, which is crucial to realize the active safety of connected vehicles in future intelligent transportation.展开更多
Handover location technology was employed for collecting road traffic information in a number of field projects, and the project results demonstrate that it is a supplementary and promising means of road traffic infor...Handover location technology was employed for collecting road traffic information in a number of field projects, and the project results demonstrate that it is a supplementary and promising means of road traffic information collection for further traffic supervision and maintenance. Because handover location technology is one kind of pattern matching based location technologies, offiine handovex location positioning is an essential problem to be studied for successfully matching mobile probes on GIS map. Offline handover location positioning method involves two stages, handover location positioning respectively via two weighted models and an optimized model based on the intermediate results obtained in the first stage. A preliminary field test is conducted on a stretch of freeway in the inner suburban region in Beijing, and performance evaluation results show that the proposed method is superior to standard least square model in location accuracy and location precision, which is an effective method of offline handover location positioning.展开更多
文摘Road condition is an important variable to measure in order to decrease road and vehicle operating/maintenance costs, but also to increase ride comfort and traffic safety. By using the built-in vibration sensor in smart phones, it is possible to collect road roughness data which can be an indicator of road condition up to a level of Class 2 or 3 in a simple and cost efficient way. Since data collection therefore is possible to be done more frequently, one can better monitor roughness changes over time. The continuous data collection can also give early warnings of changes and damage, enable new ways to work in the operational road maintenance management, and can serve as a guide for more accurate surveys for strategic asset management and pavement planning. Collected measurement data are wirelessly transferred by the operator when needed via a web service to an internet mapping server with spatial filtering functions. The measured data can be aggregated in preferred sections, as well as exported to other GlS （geographical information systems） or road management systems. Our conclusion is that measuring roads with smart phones can provide an efficient, scalable, and cost-effective way for road organizations to deliver road condition data.
基金"973"National Key Basic Research & Development Program "Research of the Basic Scientific Issues in the Traffic Congestion Bottlenecks of Big Cities"( No. 2006CB705500)Beijing Science & Technology Program "Research of the New Data Collection Technologies for Transportation Management " (No.D101100049710004)Beijing Science & Technology Program "Research of the Demonstration Platform for the In-tegrated Dynamic Operation Analysis of City Road Networks"(No. D07050600440704)
文摘This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network evaluation theories based on road "V/C". In addition, it proposes a set of theoretical and technical methods for the real-time evaluation of traffic flows for entire road networks, and for solving key technical issues, such as real-time data collection and processing in areas with no blind zones, the spatial-temporal dynamic analysis of road network traffic, and the calibration of key performance index thresholds. It also provides new technical tools for the strategic transportation planning and real-time diagnosis of road traffic. The new tools and methodology presented in this paper are validated using a case study in Beijing.
文摘At present, it is usually used the method that elevating the height of embankment to design passages of freeway to avoid transverse traffic disturbance in plain areas of China. But when design low embankment, it is difficulty for drainage or setting passages and culverts. Hengshui to Darning freeway in Hebei provence （Heng-Da freeway） is one section of Dalian to Guangzhnu freeway. This paper analyzes the characteristic of climate, geology, hydrology and low water table, good permeability stratum soil and its little and mass rain fall and deep drinking water well in the plain areas of North China when design low embankment of Heng-Da freeway, puts forward the drainage methods of water collecting filtration system to solve the drainage problem of passages and culverts, aiming at the type and the measures of the pollution on the surface, the channel collection purification infiltration system of highway uses the single composite technology of aerobic and oxygen to digest - precipitation-absorption of artificial materials percolation of soil to deal with the pollution of the rain on the road （the composite technology use the vermiculite as the material of infiltration）, which be controlled in the drinking range of the water standard. It not only efficiently solved the problem of water collected in the channel, but also supplied the groundwater. It has reached the environment-friendly road construction purpose of the sustainable development of highway construction, ＂environment friendly＂ and ＂resource conservation＂.
基金Project(4144081)supported by Beijing Natural Science Foundation,ChinaProjects(61403021,U1334211,61490705)supported by the National Natural Science Foundation of China+1 种基金Project(2015RC015)supported by the Fundamental Research Funds for Central Universities,ChinaProject supported by the Foundation of Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control,China
文摘The concept of connected vehicles is with great potentials for enhancing the road transportation systems in the future. To support the functions and applications under the connected vehicles frame, the estimation of dynamic states of the vehicles under the cooperative environments is a fundamental issue. By integrating multiple sensors, localization modules in OBUs(on-board units) require effective estimation solutions to cope with various operation conditions. Based on the filtering estimation framework for sensor fusion, an ensemble Kalman filter(En KF) is introduced to estimate the vehicle's state with observations from navigation satellites and neighborhood vehicles, and the original En KF solution is improved by using the cubature transformation to fulfill the requirements of the nonlinearity approximation capability, where the conventional ensemble analysis operation in En KF is modified to enhance the estimation performance without increasing the computational burden significantly. Simulation results from a nonlinear case and the cooperative vehicle localization scenario illustrate the capability of the proposed filter, which is crucial to realize the active safety of connected vehicles in future intelligent transportation.
基金Projects(71131001,60874078) supported by the National Natural Science Foundation of ChinaProject(NCET-08-0718) supported by Program for New Century Excellent Talents in University of China
文摘Handover location technology was employed for collecting road traffic information in a number of field projects, and the project results demonstrate that it is a supplementary and promising means of road traffic information collection for further traffic supervision and maintenance. Because handover location technology is one kind of pattern matching based location technologies, offiine handovex location positioning is an essential problem to be studied for successfully matching mobile probes on GIS map. Offline handover location positioning method involves two stages, handover location positioning respectively via two weighted models and an optimized model based on the intermediate results obtained in the first stage. A preliminary field test is conducted on a stretch of freeway in the inner suburban region in Beijing, and performance evaluation results show that the proposed method is superior to standard least square model in location accuracy and location precision, which is an effective method of offline handover location positioning.
