Fixed-time Signal Control Research Articles

Traffic Signal Control Using Web-Camera and Traffic Flow Estimation

Due to rapid urbanization, large cities in developing countries have problems with heavy traffic congestion. International aid is being provided to construct modern traffic signal infrastructure. But often such an infrastructure does not work well due to the high operating and maintenance costs and the limited knowledge of the local engineers. In this paper, we propose a signal control framework that uses image analysis to estimate traffic flows. It requires only low-cost Web cameras to support a signal control strategy based on the current traffic volume. We can estimate the traffic volumes of the roads near the traffic signals from a few observed points and then adjust the signal control. Through numerical experiments, we confirmed that the proposed framework can reduce an average travel time 20.6% compared to a fixed-time signal control. And the system also involves ideas for road crossing and ambulances.

Reducing Gridlock Probabilities via Simulation-based Signal Control

This paper studies a fixed-time signal control problem for a highly congested urban network with multimodal traffic, numerous signalized intersections, short links and a grid-type topology. The design of signal plans that indeed improve traffic conditions for a network with such complex traffic dynamics is a real challenge. In this paper, we propose a simulation-based approach. We use a simulation-based optimization algorithm to identify a signal plan for an area in eastern Manhattan (New York City, USA), where spillbacks frequently occur and impact the flows on major arterials as well as on the access/ egress to the highly congested Queensboro Bridge. We consider a signal control problem where the objective function explicitly considers queue-length information. We compare the performance of the proposed signal plan to that of the prevailing signal plan in the field. The proposed plan indeed improves traffic conditions as measured by a variety of performance metrics.

Type-2 fuzzy multi-intersection traffic signal control with differential evolution optimization

This paper proposes a multi-agent type-2 fuzzy logic control (FLC) method optimized by differential evolution (DE) for multi-intersection traffic signal control. Type-2 fuzzy sets can deal with models’ uncertainties efficiently because of its three-dimensional membership functions, but selecting suitable parameters of membership functions and rule base is not easy. DE is adopted to decide the parameters in the type-2 fuzzy system, as it is easy to understand, simple to implement and possesses low space complexity. In order to avoid the computational complexity, the expert rule base and the parameters of membership functions (MF) are optimized by turns. An eleven-intersection traffic network is studied in which each intersection is governed by the proposed controller. A secondary layer controller is set in every intersection to select the proper phase sequence. Furthermore, the communication among the adjacent intersections is implemented using multi-agent system. Simulation experiments are designed to compare communicative type-2 FLC optimized by DE with type-1 FLC, fixed-time signal control, etc. Experimental results indicate that our proposed method can enhance the vehicular throughput rate and reduce delay, queue length and parking rate efficiently.

The Impact of Detector Placement on Signalized Intersection Performance

Despite the flow fluctuations and increased traffic demand in the Macedonian cities over the last fifteen years, the Republic of Macedonia is one of those countries which still employ only the traditional systems of traffic management and control. Those are fixed control systems that certainly cause problems such as increased travel times and travel expenses as well as environmental degradation. A general call for “…something has to be done…” becomes obvious. The best practices have shown that this can be realized through unconventional solutions i.e. by means of responsive traffic management. A very reasonable example of such a system is the vehicle actuated control system that we have found to be quite challenging to do our research. Thus, we set up two folded research issues in front of us. The first one was to scientifically prove that vehicle actuated signal control can really be a reasonable substitute for a fixed time signal control, which will enhance the overall signalized intersection performance provided the timing parameters and the detector placement ŕrĺ properly designed. The second one was to indicate that such an advanced control system is feasible and sustainable for Macedonian cities. This paper focuses on the first research issue only. For this purpose, a semi-actuated signal control strategy on an appropriately chosen signalized intersection was designed. The primary objective was to determine the way in which the inductive loop detector placement from the STOP line affects the overall intersection performance. To meet the goal, two scenarios were designed: 1. Detector placement at the STOP line, and 2. Detector placement at 8 metres behind the STOP line. Emphasis was placed on the semi-actuated signal control algorithm design. The designed algorithm was then applied in the net of VISSIM in order to simulate the semi-actuated signal control process. Performance comparison analysis with the formerly pre-timed signal control strategy followed. It was concluded that the overall intersection performance could be improved both by adequate inductive loop detector placement and by interaction with signal parameters. Hence, the placement distances would have to be considered under the limitation conditions only. KEYWORDS: signalized intersection, vehicle actuated control, semi-actuated control, inductive loop detectors, simulation, delays, level of service

Stochastic system modeling and optimal control of incident-induced traffic congestion

Incident-induced traffic congestion is a critical issue in formulating urban traffic congestion problems, and also a major cause that contributes to the invalidity of traffic signal control. This paper presents a prototype of real-time local signal control method, and explores its applicability in alleviating incident-induced traffic congestion on the roadway between two adjacent intersections for incident management. The architecture includes two major parts: 1. (1) formulating time-varying lane traffic state variables and control variables under conditions of lane-blocking incidents with a discrete-time non-linear stochastic model, and 2. (2) developing a real-time control algorithm for predicting dynamically control variables. To generate efficiently traffic data used in model tests, we employed the Paramics microscopic traffic simulator, which is developed to model and analyze ITS traffic flow conditions. According to the measures of two proposed space-based incident-impact indexes, the preliminary test results indicate the superiority of the proposed real-time signal control method in comparison with fixed-time signal control modes which are currently used at the study site. We do expect that this study can stimulate research on incident management, and extend to network-wide incident-responsive traffic control for the development of advanced traffic management systems (ATMS).

Comparison of NETSIM, NETFLO I, and NETFLO II Traffic Simulation Models for Fixed-Time Signal Control

This paper documents a comparative analysis of the NETSIM, NETFLO I, and NETFLO II traffic simulation models when simulating traffic networks with fixed-time signal control. The objective was to find out whether the results of simulating the same traffic network with the three models were compatible. The three models employ different approaches to simulate traffic flow on urban street networks. Four different scenarios with varying network configurations and intersection geometries were simulated for three volume levels. The average speed and delay measures of effectiveness generated by the three models were compared for each scenario. Analysis of variance techniques were used for statistical analyses of the simulation output data. The execution speeds of the models were also compared. The quickness of simulation will be very important in the ITS applications, real-time traffic adaptive systems, and so forth. The results of this study indicated that the estimated measures of effectiveness from the three models were statistically significantly different at each level of comparison. The speed values generated by NETSIM were found to be the lowest; NETFLO II values were highest. NETFLO I values in all cases were between NETFLO II and NETSIM values. In most cases, NETFLO I values were closer to NETFLO II than to NETSIM values. Identical results were obtained from the analysis of delay values, with NETSIM delay estimates always being highest and NETFLO II values lowest. The program execution time for NETSIM and NETFLO I increased significantly as the volume level increased, whereas it practically did not change for NETFLO II. The execution times for NETSIM were found to be about 20 to 45 times higher than for NETFLO II. Even NETFLO I was found to be about 5 to 10 times faster than NETSIM.

Comparison of NETSIM, NETFLO I, and NETFLO II Traffic Simulation Models for Fixed-Time Signal Control

This paper documents a comparative analysis of the NETSIM, NETFLO I, and NETFLO II traffic simulation models when simulating traffic networks with fixed-time signal control. The objective was to find out whether the results of simulating the same traffic network with the three models were compatible. The three models employ different approaches to simulate traffic flow on urban street networks. Four different scenarios with varying network configurations and intersection geometries were simulated for three volume levels. The average speed and delay measures of effectiveness generated by the three models were compared for each scenario. Analysis of variance techniques were used for statistical analyses of the simulation output data. The execution speeds of the models were also compared. The quickness of simulation will be very important in the ITS applications, real-time traffic adaptive systems, and so forth. The results of this study indicated that the estimated measures of effectiveness from the three m...

Production of Vehicle Actuated Traffic Signal Controller for Road Work and Results of Field-Testing

Production of Vehicle Actuated Traffic Signal Controller for Road Work and Results of Field-Testing In a road construction site where pedestrians and vehicles have to use either of the inbound or the outbound lane each other on the spot, traffic control is made in accordance with flagman's instructions or indications transmitted from the fixed-time signals on the site. As to the control provided by such traffic guides, serious problems are often pointed out with the danger of collision with cars and vehicles to which the flagmans are always exposed. As to the control by means of traffic signals on the spot, seriousness is likewise brought about with the production of undesired waiting time or traffic congestion owing to the fixed-time signal control. Keeping such a situation in mind, a controller with which signal control complying with traffic demand is possible has been built up as a prototype in order to allow the burden imposed upon the flagmans to be alleviated or the safety of such injury-prone guides to be secured together with the purpose of accomplishing smoother traffic control. With the aid of the prototype, experiments on the site were conducted accompanied with the analysis taking up principally the lowering effect of the delay time. As a result, it is confirmed that the vehicle-actuated traffic signal controller developed for road work has sufficient utility and abundant usefulness.