Many signalized intersections are characterized with frequent left-turn moves. Vehicles waiting for a protected left turn may form long queues, which will increase the intersection delay and negatively impact the netw...Many signalized intersections are characterized with frequent left-turn moves. Vehicles waiting for a protected left turn may form long queues, which will increase the intersection delay and negatively impact the network performance. Researchers and practitioners across various countries underline that access management leads to a smoother traffic flow. One way of access management at intersections is to eliminate the direct left-turn maneuver. This study aims to evaluate how the traffic conditions will be affected from replacing the direct left turn with the right-turn U-turn maneuver at intersections. In case of the right-turn U-turn maneuver, a vehicle turns right instead of making the left turn and travels either to the median opening or to the next intersection to make a U-turn. Two simulation models are built using the Synchro Studio and Aimsun simulation software packages based on the data, collected from one of the busiest intersections in Tehran (Iran), to quantify the effects of replacing the direct left turn with the right-turn U-turn maneuver on the intersection and network performance. Results of a comprehensive simulation analysis indicate that the proposed access management treatment not only significantly reduces the total vehicle queue length and the total delay at the considered intersection, but also decreases the total network delay and the total travel time. Furthermore, elimination of the direct left turn increases the number of vehicles entering the network.展开更多
In Changchun, China, roundabouts are fairly common. They are often designed to connect the main roads because of their ability to reduce conflict points, making them safer than other intersections. They can also beaut...In Changchun, China, roundabouts are fairly common. They are often designed to connect the main roads because of their ability to reduce conflict points, making them safer than other intersections. They can also beautify the city when the central islands are landscaped. However, with increasing traffic, they may not function well and may even paralyze the road network. This means that it is important to evaluate the performance of roundabouts promptly, and to make necessary improvements if required. Using several roundabouts in Changchun as case studies, this article uses V/C ratio and delay to evaluate roundabout performance. Based on the result of evaluation, the micro-simulation model of the poorly-performing roundabout is built and enhancement is proposed.展开更多
Purpose–This research paper aims to investigate the effects of gradual deployment of market penetration rates(MPR)of connected vehicles(MPR of CVs)on delay time and fuel consumption.Design/methodology/approach–A rea...Purpose–This research paper aims to investigate the effects of gradual deployment of market penetration rates(MPR)of connected vehicles(MPR of CVs)on delay time and fuel consumption.Design/methodology/approach–A real-world origin-destination demand matrix survey was conducted in Boston,MA to identify the number of peak hour passing vehicles in the case study.Findings–The results showed that as the number of CVs(MPR)in the network increases,the total delay time decreases by an average of 14%and the fuel consumption decreases by an average of 56%,respectively,from scenarios 3 to 15 compared to scenario 2.Research limitations/implications–The first limitation of this study was considering a small network.The considered network shows a small part of the case study.Originality/value–This study can be a milestone for future research regarding gradual deployment of CVs’effects on transport networks.Efficient policy(s)may define based on the results of this network for Brockton transport network.展开更多
文摘Many signalized intersections are characterized with frequent left-turn moves. Vehicles waiting for a protected left turn may form long queues, which will increase the intersection delay and negatively impact the network performance. Researchers and practitioners across various countries underline that access management leads to a smoother traffic flow. One way of access management at intersections is to eliminate the direct left-turn maneuver. This study aims to evaluate how the traffic conditions will be affected from replacing the direct left turn with the right-turn U-turn maneuver at intersections. In case of the right-turn U-turn maneuver, a vehicle turns right instead of making the left turn and travels either to the median opening or to the next intersection to make a U-turn. Two simulation models are built using the Synchro Studio and Aimsun simulation software packages based on the data, collected from one of the busiest intersections in Tehran (Iran), to quantify the effects of replacing the direct left turn with the right-turn U-turn maneuver on the intersection and network performance. Results of a comprehensive simulation analysis indicate that the proposed access management treatment not only significantly reduces the total vehicle queue length and the total delay at the considered intersection, but also decreases the total network delay and the total travel time. Furthermore, elimination of the direct left turn increases the number of vehicles entering the network.
文摘In Changchun, China, roundabouts are fairly common. They are often designed to connect the main roads because of their ability to reduce conflict points, making them safer than other intersections. They can also beautify the city when the central islands are landscaped. However, with increasing traffic, they may not function well and may even paralyze the road network. This means that it is important to evaluate the performance of roundabouts promptly, and to make necessary improvements if required. Using several roundabouts in Changchun as case studies, this article uses V/C ratio and delay to evaluate roundabout performance. Based on the result of evaluation, the micro-simulation model of the poorly-performing roundabout is built and enhancement is proposed.
文摘Purpose–This research paper aims to investigate the effects of gradual deployment of market penetration rates(MPR)of connected vehicles(MPR of CVs)on delay time and fuel consumption.Design/methodology/approach–A real-world origin-destination demand matrix survey was conducted in Boston,MA to identify the number of peak hour passing vehicles in the case study.Findings–The results showed that as the number of CVs(MPR)in the network increases,the total delay time decreases by an average of 14%and the fuel consumption decreases by an average of 56%,respectively,from scenarios 3 to 15 compared to scenario 2.Research limitations/implications–The first limitation of this study was considering a small network.The considered network shows a small part of the case study.Originality/value–This study can be a milestone for future research regarding gradual deployment of CVs’effects on transport networks.Efficient policy(s)may define based on the results of this network for Brockton transport network.
