Jifu Guo

Calibration of Vissim for Bus Rapid Transit Systems in Beijing Using GPS Data

Bus Rapid Transit (BRT) systems have grown in popularity in recent years. With the rapid development of computer technologies, using microscopic simulation models to study various strategies on planning, implementation and operation of BRT systems has become a hot research area in the field of public transportation. To make the simulation models accurately replicate field traffic conditions, model calibration is crucial. This paper presents an approach for calibrating the microscopic traffic simulation model VISSIM using Global Positioning System (GPS) data for application to Beijing BRT systems. The Sum of Squared Error (SSE) of the collected versus simulated vehicle speeds at the cross-sections along the test route is specified as the evaluation index. A Genetic Algorithm is adopted as the optimization tool to minimize the SSE. Taking the Beijing North-South Central Axis BRT Corridor as a case study, it shows that the proposed approach is a practical and effective method for the model calibration.

Microscopic Traffic Simulation Approach to the Capacity Impact Analysis of Weaving Sections for the Exclusive Bus Lanes on an Urban Expressway

This paper presents a microscopic traffic simulation approach to the capacity impact analysis of weaving sections caused by the installation of exclusive bus lanes (XBLs) on urban expressways. Three typical configurations of XBL in Beijing are identified, including median bus lane with off-on-ramp, curbside bus lane with on-off-ramp, and curbside bus lane with off-on-ramp. Then, the weaving section length, headway, mainline volume, as well as off-ramp and on-ramp volumes for general traffic are considered as parameters in designing simulation scenarios. Finally, the microscopic simulation is executed, by which the capacity of general traffic for weaving sections is estimated and the impact of the weaving section length and headway on the capacity is evaluated. It is found that the weaving section length and headway have different impacts on the capacity of general traffic in different configurations. The results also provide that the weaving section length and headway are more sensitive in the on-off-ramp than in the off-on-ramp scenario with the curb bus lane.

Microscopic Simulation Approach to Effectiveness Analysis of Transit Signal Priority for Bus Rapid Transit: A Case Study in Beijing

Transit signal priority (TSP) is one of the critical components of bus rapid transit (BRT) and a key technology in enhancing its operational efficacy. It not only provides priority to the BRT vehicle but also manages the trade-off between the delay of buses at an intersection and the impacts on other traffic. This paper focuses on the design and evaluation of a simulation of signal priority for BRT under mixed traffic flow conditions. Taking the Southern Axis BRT Line 1 in Beijing as a case study, different signal priority strategies, including green extension, red truncation, and special phase insertion, are developed for the signalized intersection along the BRT route. A signal coordination plan is designed for the section composed of four intersections in the BRT system. The study uses the VISSIM microscopic traffic simulation model to analyze the impacts of traffic parameters, especially those of nonmotorized traffic, on the effectiveness of TSP along the corridor. Simulation results indicated that the BRT vehicles would typically benefit from transit priority with travel times savings and delay reduction, as well as greater schedule adherence, and suggest that these benefits may be obtained with little negative impacts to the overall system. The results also indicated that the volume of nonmotorized traffic is one of the most important factors that influence the effectiveness of TSP implementation in a mixed traffic flow.

Simulated Analysis of Exclusive Bus Lanes on Expressways: Case Study in Beijing, China

Deploying exclusive bus lanes is considered an important strategy for supporting public transit priority policy. This paper uses a simulation approach to evaluate planned exclusive bus lanes on expressways in Beijing, China. Two scenarios for deploying exclusive bus lanes--a curbside bus lane scenario and a median bus lane scenario--were designed. Then, a micro-simulation network platform, using VISSIM, was established and calibrated, with all relative errors between the simulated time varying speeds and the field speeds less than 15 percent. Afterwards, the two bus lane scenarios were simulated, evaluated, and subsequently compared with current traffic conditions without bus lanes. It was found that for both the mainline and the whole network, the operational efficiencies of buses, general traffic, and all mixed traffic are improved with the deployment of exclusive bus lanes. Further, the median bus lane scenario slightly outperforms the curbside bus lane scenario in this case.

Development of Beijing Regional Intelligent Transportation System architecture

Regional Intelligent Transportation System (ITS) architecture, which is usually developed in accordance with national ITS architecture, provides the framework and guidance for developing and deploying ITS technologies in a region. The development of Beijing Regional ITS Architecture, which is the essential part of the Beijing ITS Strategic Planning, is rather an exploring initiative due to the fact that the Chinas national ITS architecture is currently being updated. This paper is intended to present the methodology that has been used in the development of Beijing Regional ITS Architecture. First, the functional needs are analyzed based on a comprehensive survey. Then, the functional needs are mapped to user services as defined and required by the Chinas national ITS architecture. The concept of market packages, which is not included in the current version of Chinas national ITS architecture but was utilized in the U.S. national ITS architecture, is introduced and applied, with which the user services are converted into market packages. Subsequently, the physical architecture composed of physical entities and architecture flows are developed. Finally, some conclusions are provided and the additional research is recommended.