Microscopic traffic simulation is an invaluable tool for traffic research. In recent years, both the scope of research and the capabilities of the tools have been extended considerably. This article presents the latest developments concerning intermodal traffic solutions, simulator coupling and model development and validation on the example of the open source traffic simulator SUMO.

Transitions of Control (ToC) play an important role in the simulative impact assessment of automated driving because they may represent major perturbations of smooth and safe traffic operation. The drivers' efforts to take back control from the automation are accompanied by a change of driving behavior and may lead to increased error rates, altered headways, safety critical situations, and, in the case of a failing takeover, even to minimum risk maneuvers. In this work we present modeling approaches for these processes, which have been introduced into SUMO recently in the framework of the TransAID project. Further, we discuss the results of an evaluation of some hierarchical traffic management (TM) procedures devised to ameliorate related disturbances in transition areas, i.e., zones of increased probability for the automation to request a ToC.

To overcome the data insufficiency and achieve reasonable simulation results this paper has proposed to use the Webster's delay model, together with given route information, to optimize traffic signal programs generated by SUMO. The pre-timed traffic signal cycle length and the green time allocation will be optimized for each given traffic signal program accordingly. The proposed approach takes also signal sharing among intersections into account. Two cases studies, i.e. one single intersection and one traffic signal controlled area, are conducted to evaluate the performance of the proposed approach. The simulation results show that there are apparent reductions in average trip duration, waiting time, time loss and departure delay with use of the proposed approach. The traffic efficiency can be improved consequently. In addition, some issues are pointed out as future works for extending the proposed approach.

in this paper, real-time vehicular data from video traffic detection (VTD) are used for minimizing the travel delay at intersections and a real-time traffic optimization model, based on the SUMO traffic simulation software, is established accordingly. The proposed model is implemented in a small industrial control computer which serves as the communication interface between the traffic signal control system, the traffic simulation and optimization model and the real-time video traffic detection equipment to optimize the respective signal timing plans. The decision to shorten or extend the respective green time can be made at each second under the current development. To verify the results of the simulation study a field study is undertaken in Hefei, China. The overall intersection performances before and after the signal timing optimization are calculated and compared. The results show that the method proposed in this paper can significantly minimize the vehicle delay and the corresponding air pollution in real time.

With the consideration of the uneven traffic volume distribution at intersections on urban arterials, this paper aims to minimize the overall passenger delay (buses and private vehicles) at intersections and identify the applicable conditions of the proposed method with field data. The overlapping phase-based signal control logic and the bus priority control algorithm under two-way signal coordination on arterial roads are proposed. The vehicular capacities and occupancies for buses and passenger cars are considered in the evaluation of the method performance. A field test was carried out at two major intersections on an arterial road in Hefei, China. With the test data, the proposed method is examined and the possible influencing factors are analyzed for identifying the corresponding applicable conditions. The analysis result shows that the application of the overlapping phase helps to provide a relatively flexible signal control for the varying traffic demands at intersections. Compared to the conventional phase, it isof more practical significance to consider overlapping phase and apply bussignal priority control under two-way signal coordination according to the condition of uneven traffic volumedistribution at intersections on urban arterials. The proposed method can effectively decrease the total passenger delay at the intersections on urban arterials under certain applicable conditions. The possible factors influencing the method applicability are identified as well. It is verified that bus signal priority control under the two-way signal coordination, based on overlapping phases, is more conducive to improving traffic efficiency on urban arterials. Regarding the influencing factors and the applicability of the proposed method, the results show that not all situations are conducive to decreasing passenger delay at intersections. The proposed method should be applied under certain applicable conditions and principles in order to efficiently and effectively improve the traffic efficiency on arterial roads.

Air pollution has been a serious problem in China for many years. One of the main reasons for this is the rapid growth in motorized traffic which results in lots of traffic congestion in metropolitan areas. This study aims to monitor and reduce traffic's impact on air quality at intersections, with the use of the object detecting and tracking technique and traffic signal control optimization. A field campaign is executed at a selected intersection in Hefei, China and the collected emission data is used for examining and ensuring how reasonable the simulated emission productions are. The simulative approach shows that the proposed signal control method greatly increases the efficiency of the traffic operation and, at the same time, reduces the amount of emission production. A field test of the proposed method is under preparation for verifying the simulation results and will be carried out within two months.

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