In the U.S.and worldwide,driver behavior within an area close to high-speed signalized intersections-the dilemma zone,can be a major safety concern especially for heavy trucks.A variety of mechanisms are available as ...In the U.S.and worldwide,driver behavior within an area close to high-speed signalized intersections-the dilemma zone,can be a major safety concern especially for heavy trucks.A variety of mechanisms are available as countermeasures for the dilemma zone problem.In Nebraska,the Department of Roads has developed and implemented an Actuated Advance Warning dilemma zone protection system.The system has been effective at improving traffic safety in isolated applications.However,the system is yet to be used at signalized intersections operating in the coordinated mode.This paper presents results from a simulation study that assessed the potential deployment of the system on arterials where the signals are closely spaced and operate in a coordinated mode.The analysis indicated that,on average,there were 30%,7%and 30%reductions in the number of rear-end,lane change and crossing conflicts.The system also improved relative productivity by processing more vehicles.展开更多
In the U.S.and worldwide,driver behavior within an area close to high-speed signalized intersections-the dilemma zone,can be a major safety concern especially for heavy trucks.A variety of mechanisms are available as ...In the U.S.and worldwide,driver behavior within an area close to high-speed signalized intersections-the dilemma zone,can be a major safety concern especially for heavy trucks.A variety of mechanisms are available as countermeasures for the dilemma zone problem.In Nebraska,the Department of Roads has developed and implemented an Actuated Advance Warning dilemma zone protection system.The system has being effective at improving traffic safety in isolated applications.However,the system is yet to be used at signalized intersections operating in the coordinated mode.This paper presents results from a simulation study that assessed the potential deployment of the system on arterials where the signals are closely spaced and operate in a coordinated mode.The analysis indicated that,on average,there were 30%,7%and 30%reductions in the number of rear-end,lane change and crossing conflicts.The system also improved relative productivity by processing more vehicles.展开更多
Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the host clay formation ...Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the host clay formation is considered as a principal barrier on which the fulfillment of key safety functions rests. Between 2006 and 2010, the European Commission project TIMODAZ, which gathered 15 partners from 8 countries, has investigated the coupled thermo-hydro-mechanical （THM） effects on clay formations for geological disposal of radioactive waste, and specific attention was paid to investigating the thermal effect on the evolution of the damaged zone （DZ）. Three types of potential host clay formations were investigated： the Boom Clay （Belgium）, the Opalinus Clay （Switzerland） and the Callovo-Oxfordian argillite （France）. Intensive experimental （laboratory and in situ in underground research laboratories） and numerical studies have been performed. Multi-scale approach was used in the course of the project. High degree of similarities between the failure modes, sealing process, stress paths, deformation, etc., observed in laboratories and in situ has been obtained, which increased the confidence in the applicability of laboratory test results and up-scaling perspective. The results of the laboratory and in situ tests obtained allowed the parameters for numerical models at various scales to be derived and provided the basis for the simplified performance assessment models that are used to assess the long-term safety of a repository. The good cooperation between the numerical modeler and experimenters has allowed an in-depth analysis of the experimental results and thus better understanding the underlying processes, and consequently increased the capabilities to model the THM effects in claystones. This paper presents the main achievements obtained by TIMODAZ project and shows how a European scientific community investigates a problem of concern in a collaborative way and how the obtained main results are applied to the performance assessment of a geological repository.展开更多
文摘In the U.S.and worldwide,driver behavior within an area close to high-speed signalized intersections-the dilemma zone,can be a major safety concern especially for heavy trucks.A variety of mechanisms are available as countermeasures for the dilemma zone problem.In Nebraska,the Department of Roads has developed and implemented an Actuated Advance Warning dilemma zone protection system.The system has been effective at improving traffic safety in isolated applications.However,the system is yet to be used at signalized intersections operating in the coordinated mode.This paper presents results from a simulation study that assessed the potential deployment of the system on arterials where the signals are closely spaced and operate in a coordinated mode.The analysis indicated that,on average,there were 30%,7%and 30%reductions in the number of rear-end,lane change and crossing conflicts.The system also improved relative productivity by processing more vehicles.
基金The authors would like to acknowledge the contributions of numerous individuals and organizations that made the successful completion of this study possible.We are especially grateful to the Federal Highway Administration for making the Surrogate Safety Assessment Module available to usand the business team at the Mid-America Transportation Center who provided technical support.
文摘In the U.S.and worldwide,driver behavior within an area close to high-speed signalized intersections-the dilemma zone,can be a major safety concern especially for heavy trucks.A variety of mechanisms are available as countermeasures for the dilemma zone problem.In Nebraska,the Department of Roads has developed and implemented an Actuated Advance Warning dilemma zone protection system.The system has being effective at improving traffic safety in isolated applications.However,the system is yet to be used at signalized intersections operating in the coordinated mode.This paper presents results from a simulation study that assessed the potential deployment of the system on arterials where the signals are closely spaced and operate in a coordinated mode.The analysis indicated that,on average,there were 30%,7%and 30%reductions in the number of rear-end,lane change and crossing conflicts.The system also improved relative productivity by processing more vehicles.
基金funded by the European Commission through the TIMODAZ project within the 6th framework programme (Contract Number: FI6W-CT-2007-036449)
文摘Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the host clay formation is considered as a principal barrier on which the fulfillment of key safety functions rests. Between 2006 and 2010, the European Commission project TIMODAZ, which gathered 15 partners from 8 countries, has investigated the coupled thermo-hydro-mechanical （THM） effects on clay formations for geological disposal of radioactive waste, and specific attention was paid to investigating the thermal effect on the evolution of the damaged zone （DZ）. Three types of potential host clay formations were investigated： the Boom Clay （Belgium）, the Opalinus Clay （Switzerland） and the Callovo-Oxfordian argillite （France）. Intensive experimental （laboratory and in situ in underground research laboratories） and numerical studies have been performed. Multi-scale approach was used in the course of the project. High degree of similarities between the failure modes, sealing process, stress paths, deformation, etc., observed in laboratories and in situ has been obtained, which increased the confidence in the applicability of laboratory test results and up-scaling perspective. The results of the laboratory and in situ tests obtained allowed the parameters for numerical models at various scales to be derived and provided the basis for the simplified performance assessment models that are used to assess the long-term safety of a repository. The good cooperation between the numerical modeler and experimenters has allowed an in-depth analysis of the experimental results and thus better understanding the underlying processes, and consequently increased the capabilities to model the THM effects in claystones. This paper presents the main achievements obtained by TIMODAZ project and shows how a European scientific community investigates a problem of concern in a collaborative way and how the obtained main results are applied to the performance assessment of a geological repository.
