In a multi-lane area,the increasing randomness of lane changes contributes to traffic insecurity and local traffic flow instability.A study on safe lane shifting activity that focuses on threat assessment under real-t...In a multi-lane area,the increasing randomness of lane changes contributes to traffic insecurity and local traffic flow instability.A study on safe lane shifting activity that focuses on threat assessment under real-time knowledge is necessary to enhance smooth vehicle flow.This paper proposed amore comprehensive lane changing guidance rule to investigate the status of surrounding vehicles to accommodate future vehicle-on-road collaborative environments based on these parameters 1)lane change demand and 2)treat assessment function.The collaborative relationships between vehicles are analyzed using a cellular automata model based on their location,velocity,and acceleration.We analyze and examine the relationship between the number of lanes and traffic flow when the road capacity is heavily mined via intelligent lane changing.Our analysis can further provide theoretical guidance for the selection of road expansion mode.Our proposed STCA-L is compared based on the average speed,average flow,lane changing frequency,spatial and temporal pattern of STCA,STCA-I,and STCA-S,and STCA-M under different vehicle densities.The numerical simulation results show that our proposed STCA-L provides themost flexible lane changing guidance in the multi-lanes road.Moreover,the simulated results show that the exponential growth of physical space cannot provide the corresponding increase in the average flow of vehicles.展开更多
为了提高雾与能见度的预报水平,对业务上常用的两种能见度诊断方案,即Stoelinga and Warner(SW)方案与Forecast Systems Laboratory(FSL)方案的改进进行预报试验,SW方案基于Gultepe方案考虑了液态水粒子数浓度对能见度的影响,FSL改进方...为了提高雾与能见度的预报水平,对业务上常用的两种能见度诊断方案,即Stoelinga and Warner(SW)方案与Forecast Systems Laboratory(FSL)方案的改进进行预报试验,SW方案基于Gultepe方案考虑了液态水粒子数浓度对能见度的影响,FSL改进方案中利用了递减平均法对公式中用到的温度与露点温度进行订正,并用其重新计算公式中的相对湿度。基于山东省气象科学研究所逐时更新循环(hourly update cycle,HUC)业务模式输出结果,从2015—2016年选取10次雾天气过程,并详细分析了2015年11月13—14日这次雾天气过程的预报结果,比较了改进前后各方案对雾与能见度的预报效果,结果显示:在模式预报的雨水含量占总液态含水量比例较大的预报时效,改进后的SW方案对雾与能见度预报效果优于原始方案,在模式预报液态含水量接近0的预报时效,改进前后的SW方案对雾与能见度的预报效果相当;利用订正的温度与露点温度重新计算相对湿度,其平均绝对误差(mean absolute error,MAE)降低明显的预报时段,改进后的FSL方案对雾与能见度的预报效果大大提升。将两种改进后的方案相融合并进行预报试验,结果显示,综合对能见度与雾的预报效果,Combined Visibility(CVIS)方案要优于其他两种改进方案。展开更多
为保证救护车、消防车等紧急车辆安全、高效率地完成应急救援任务,基于车路协同系统(CVIS),综合利用交通信号协调配时与车速引导,提出紧急车辆在交叉口的改进型优先通行控制方法。利用VISSIM与Visual Studio 2008搭建的联合仿真试验平...为保证救护车、消防车等紧急车辆安全、高效率地完成应急救援任务,基于车路协同系统(CVIS),综合利用交通信号协调配时与车速引导,提出紧急车辆在交叉口的改进型优先通行控制方法。利用VISSIM与Visual Studio 2008搭建的联合仿真试验平台进行模拟试验,对比分析仿真环境中不同控制方法下紧急车辆通过交叉口的实际运行数据。结果表明,相比于传统优先通行控制方法与定周期控制方法,采用改进型优先通行控制方法,可使紧急车辆在交叉口的平均行程时间分别减少19%与32%,平均速度分别提高18%与37%,平均排队长度分别减少66%与84%,停车次数、平均停车次数也显著减少。展开更多
基金supported in part by the National Natural Science Foundation of China(No.51905405)Basic Research Program of Natural Science of Shaanxi Province(No.2022JM-407)Guiding Program of Science and Technology of China Textile Industry Federation(No.2020106).
文摘In a multi-lane area,the increasing randomness of lane changes contributes to traffic insecurity and local traffic flow instability.A study on safe lane shifting activity that focuses on threat assessment under real-time knowledge is necessary to enhance smooth vehicle flow.This paper proposed amore comprehensive lane changing guidance rule to investigate the status of surrounding vehicles to accommodate future vehicle-on-road collaborative environments based on these parameters 1)lane change demand and 2)treat assessment function.The collaborative relationships between vehicles are analyzed using a cellular automata model based on their location,velocity,and acceleration.We analyze and examine the relationship between the number of lanes and traffic flow when the road capacity is heavily mined via intelligent lane changing.Our analysis can further provide theoretical guidance for the selection of road expansion mode.Our proposed STCA-L is compared based on the average speed,average flow,lane changing frequency,spatial and temporal pattern of STCA,STCA-I,and STCA-S,and STCA-M under different vehicle densities.The numerical simulation results show that our proposed STCA-L provides themost flexible lane changing guidance in the multi-lanes road.Moreover,the simulated results show that the exponential growth of physical space cannot provide the corresponding increase in the average flow of vehicles.
文摘为了提高雾与能见度的预报水平,对业务上常用的两种能见度诊断方案,即Stoelinga and Warner(SW)方案与Forecast Systems Laboratory(FSL)方案的改进进行预报试验,SW方案基于Gultepe方案考虑了液态水粒子数浓度对能见度的影响,FSL改进方案中利用了递减平均法对公式中用到的温度与露点温度进行订正,并用其重新计算公式中的相对湿度。基于山东省气象科学研究所逐时更新循环(hourly update cycle,HUC)业务模式输出结果,从2015—2016年选取10次雾天气过程,并详细分析了2015年11月13—14日这次雾天气过程的预报结果,比较了改进前后各方案对雾与能见度的预报效果,结果显示:在模式预报的雨水含量占总液态含水量比例较大的预报时效,改进后的SW方案对雾与能见度预报效果优于原始方案,在模式预报液态含水量接近0的预报时效,改进前后的SW方案对雾与能见度的预报效果相当;利用订正的温度与露点温度重新计算相对湿度,其平均绝对误差(mean absolute error,MAE)降低明显的预报时段,改进后的FSL方案对雾与能见度的预报效果大大提升。将两种改进后的方案相融合并进行预报试验,结果显示,综合对能见度与雾的预报效果,Combined Visibility(CVIS)方案要优于其他两种改进方案。
文摘为保证救护车、消防车等紧急车辆安全、高效率地完成应急救援任务,基于车路协同系统(CVIS),综合利用交通信号协调配时与车速引导,提出紧急车辆在交叉口的改进型优先通行控制方法。利用VISSIM与Visual Studio 2008搭建的联合仿真试验平台进行模拟试验,对比分析仿真环境中不同控制方法下紧急车辆通过交叉口的实际运行数据。结果表明,相比于传统优先通行控制方法与定周期控制方法,采用改进型优先通行控制方法,可使紧急车辆在交叉口的平均行程时间分别减少19%与32%,平均速度分别提高18%与37%,平均排队长度分别减少66%与84%,停车次数、平均停车次数也显著减少。
