Flyovers are constructed to manage heavy through movement. However, traffic operations underneath a flyover remain unmanaged and often pose a major con- cern in developing countries with non-lane-based hetero- geneous...Flyovers are constructed to manage heavy through movement. However, traffic operations underneath a flyover remain unmanaged and often pose a major con- cern in developing countries with non-lane-based hetero- geneous traffic. This may reduce the overall benefit of a flyover. An alternative intersection layout is proposed to improve traffic operations at the intersection underneath a flyover. The proposed layout segregates the traffic move- ments through effective channelization. A traffic island is also proposed in the middle of the intersection to facilitate concurrent right-turning movements. This layout helps in eliminating a signal phase and cuts down traffic cycle time by 40 %. A microsimulation-based traffic simulation model is developed for the evaluation of the proposed layout. The simulation model demonstrates effectiveness of the proposed layout. Average delay and average queue length are compared to measure the effectiveness. Traffic volume sensitivity analysis is conducted to estimate the capacity of the proposed layout. An intersection underneath a flyover along the Eastern Expressway in Mumbai is considered for the case study. The effectiveness of the proposed layout at the study location for varying flow level is evaluated by comparing average delay, average stop delay, average number of stops per vehicle, average queue length, and maximum queue length.展开更多
A significant proportion of urban crashes,especially serious and fatal crashes,occur at traffic signals.Many of the black-spots in both Australia and New Zealand cities occur at high volume and/or high-speed traffic s...A significant proportion of urban crashes,especially serious and fatal crashes,occur at traffic signals.Many of the black-spots in both Australia and New Zealand cities occur at high volume and/or high-speed traffic signals.Given this,crash reduction studies often focus on the major signalised intersections.However,there is limited information that links the phasing configuration,degree of saturation and overall cycle time to crashes.While a number of analysis tools are available for assessing the efficiency of intersections,there are very few tools that can assist engineers in assessing the safety effects of intersection upgrades and new intersections.Safety performance functions have been developed to help quantify the safety impact of various traffic signal phasing configurations and level of intersection congestion at low and high-speed traffic signals in New Zealand and Australia.Data from 238 signalised intersection sites in Auckland,Wellington,Christchurch,Hamilton,Dunedin and Melbourne was used to develop crash prediction models for key crash-causing movements at traffic signals.Different variables(road features)effect each crash type.The models indicate that the safety of intersections can be improved by longer cycle times and longer lost inter-green times,especially all-red time,using fully protected right turns and by extending the length of right turn bays.The exception is at intersections with lots of pedestrians where shorter cycle times are preferred as pedestrian crashes increase with longer wait times.A number of factors have a negative impact on safety including,free left turns,more approach lanes,intersection arms operating near or over capacity in peak periods and higher speed limits.展开更多
充电站优化布局对新能源汽车产业持续高质量发展具有重要意义。以最大覆盖模型为基础,充分考虑因充电站服务半径缩短而导致充电需求覆盖可能性减小的问题,将充电站覆盖用户需求概率作为充电服务半径的分段函数,把概率覆盖引入到充电站...充电站优化布局对新能源汽车产业持续高质量发展具有重要意义。以最大覆盖模型为基础,充分考虑因充电站服务半径缩短而导致充电需求覆盖可能性减小的问题,将充电站覆盖用户需求概率作为充电服务半径的分段函数,把概率覆盖引入到充电站布局优化中,建立了新的充电站随机概率覆盖模型;以重庆市南岸区为例,通过爬取兴趣点(point of interest,POI)数据,采用遗传算法进行求解,并对候选充电站综合效用进行了敏感性分析。研究结果表明:随着服务半径缩短,需求覆盖量也随之减小;通过新建充电站能有效地提高充电需求覆盖量。展开更多
文摘Flyovers are constructed to manage heavy through movement. However, traffic operations underneath a flyover remain unmanaged and often pose a major con- cern in developing countries with non-lane-based hetero- geneous traffic. This may reduce the overall benefit of a flyover. An alternative intersection layout is proposed to improve traffic operations at the intersection underneath a flyover. The proposed layout segregates the traffic move- ments through effective channelization. A traffic island is also proposed in the middle of the intersection to facilitate concurrent right-turning movements. This layout helps in eliminating a signal phase and cuts down traffic cycle time by 40 %. A microsimulation-based traffic simulation model is developed for the evaluation of the proposed layout. The simulation model demonstrates effectiveness of the proposed layout. Average delay and average queue length are compared to measure the effectiveness. Traffic volume sensitivity analysis is conducted to estimate the capacity of the proposed layout. An intersection underneath a flyover along the Eastern Expressway in Mumbai is considered for the case study. The effectiveness of the proposed layout at the study location for varying flow level is evaluated by comparing average delay, average stop delay, average number of stops per vehicle, average queue length, and maximum queue length.
文摘A significant proportion of urban crashes,especially serious and fatal crashes,occur at traffic signals.Many of the black-spots in both Australia and New Zealand cities occur at high volume and/or high-speed traffic signals.Given this,crash reduction studies often focus on the major signalised intersections.However,there is limited information that links the phasing configuration,degree of saturation and overall cycle time to crashes.While a number of analysis tools are available for assessing the efficiency of intersections,there are very few tools that can assist engineers in assessing the safety effects of intersection upgrades and new intersections.Safety performance functions have been developed to help quantify the safety impact of various traffic signal phasing configurations and level of intersection congestion at low and high-speed traffic signals in New Zealand and Australia.Data from 238 signalised intersection sites in Auckland,Wellington,Christchurch,Hamilton,Dunedin and Melbourne was used to develop crash prediction models for key crash-causing movements at traffic signals.Different variables(road features)effect each crash type.The models indicate that the safety of intersections can be improved by longer cycle times and longer lost inter-green times,especially all-red time,using fully protected right turns and by extending the length of right turn bays.The exception is at intersections with lots of pedestrians where shorter cycle times are preferred as pedestrian crashes increase with longer wait times.A number of factors have a negative impact on safety including,free left turns,more approach lanes,intersection arms operating near or over capacity in peak periods and higher speed limits.
文摘充电站优化布局对新能源汽车产业持续高质量发展具有重要意义。以最大覆盖模型为基础,充分考虑因充电站服务半径缩短而导致充电需求覆盖可能性减小的问题,将充电站覆盖用户需求概率作为充电服务半径的分段函数,把概率覆盖引入到充电站布局优化中,建立了新的充电站随机概率覆盖模型;以重庆市南岸区为例,通过爬取兴趣点(point of interest,POI)数据,采用遗传算法进行求解,并对候选充电站综合效用进行了敏感性分析。研究结果表明:随着服务半径缩短,需求覆盖量也随之减小;通过新建充电站能有效地提高充电需求覆盖量。
