Synchronization Of Traffic Signals Research Articles

Traffic Signal Synchronization and Dynamic Control

Abstract: During the past decade, there has been a significant increase in popu- lation combined with ever-increasing automobile sales, resulting in increased traffic around the world. Although modern city infrastructure is designed to han-dle this increasing traffic, it is very difficult to deal with traffic in unplanned partsof cities or cities that were developed hundreds of years ago where congestion was not taken into account. During our analysis, we found that it is not possible to synchronize all the signals in such parts of cities as the distance between each traffic signal is different, with some intersections having very high traffic and the very next having low traffic. We came to the conclusion that although it is im- possible to synchronize all the traffic signals, we can form clusters of 2-3 inter- sections that can be synchronized and the intersection with the highest amount oftraffic will be dynamic i.e., the lane with the highest traffic will get more time. These traffic signals can then be connected through the internet and linked to maps which can show upcoming traffic signals and their real-time status

Performance Analysis of Decentralized VS Centralized Control for the Traffic Signal Synchronization Problem

This paper suggests the adoption of a spatial decomposition method to solve the signal synchronization problem. A good signal setting maximizes the number of vehicles passing through intersections, while minimizing gas emissions and possible delays experienced by drivers. The signals synchronization issue can be defined as the problem of finding the offsets, the green timings, and the cycle length for a series of controlled intersections, minimizing the total delay of the network subject to admissibility constraints. In this paper, the authors optimized the signal setting through a new Surrogate Method calculating the objective function via the CTM UT model while performing a simulation. A spatial decomposition approach is here suggested with a simultaneous analysis of different levels of cooperation among subnetworks. This study tries to identify a subnetwork that might be representative of the entire network while taking into consideration two factors: efficiency and efficacy. A comparison between centralized and decentralized control is performed.

A New Traffic Signal Control Method Based on Hybrid Colored Petri Net in Isolated Intersections

To optimize the traffic signal control of isolated intersections, a hybrid colored Petri net is proposed to model the urban signalized intersection, which consists of a traffic signal control module and a traffic flow module. Furthermore, a new feedback-based signal control method based on the Petri net model is presented. The method performs an online optimization and synchronization of traffic signals. After finishing the minimum green time of current phase, whether extending the current phase’s green time is determined by comparing a performance index of the current phase with the candidate phases. The performance index is based on the number of queued vehicles and the red time of candidate phases. Finally, experiments on field data are carried out against the fixed time-of-day control strategy to compare their performances on average vehicle delay. Results verified the feasibility of the Petri net model and the effectiveness of the proposed method.

A multi-path progression model for synchronization of arterial traffic signals

To contend with congestion and spillback on commuting arterials, serving as connectors between freeway and surface-street flows, this paper presents three multi-path progression models to offer progression bands for multiple critical path-flows contributing to the high volume in each arterial link. The first proposed model is a direct extension of MAXBAND under a predetermined phasing plan, but using the path-flow data to yield the progression bands. The second model further takes the phase sequence at each intersection as a decision variable, and concurrently optimizes the signal plans with offsets for the entire arterial. Due to the competing nature of multi-path progression flows over the same green duration, the third model is proposed with a function to automatically select the optimal number of paths in their bandwidths maximization process. The results of extensive simulation studies have shown that the proposed models outperform conventional design methods, such as MAXBAND or TRANSYT, especially for those arterials with multiple heavy path-flows. The research results from this study have also reflected the need to collect more traffic pattern data such as major path-flow volumes, in addition to the typical intersection volume counts.

Traffic signal synchronization in the saturated high-density grid road network.

Most existing traffic signal synchronization strategies do not perform well in the saturated high-density grid road network (HGRN). Traffic congestion often occurs in the saturated HGRN, and the mobility of the network is difficult to restore. In order to alleviate traffic congestion and to improve traffic efficiency in the network, the study proposes a regional traffic signal synchronization strategy, named the long green and long red (LGLR) traffic signal synchronization strategy. The essence of the strategy is to control the formation and dissipation of queues and to maximize the efficiency of traffic flows at signalized intersections in the saturated HGRN. With this strategy, the same signal control timing plan is used at all signalized intersections in the HGRN, and the straight phase of the control timing plan has a long green time and a long red time. Therefore, continuous traffic flows can be maintained when vehicles travel, and traffic congestion can be alleviated when vehicles stop. Using the strategy, the LGLR traffic signal synchronization model is developed, with the objective of minimizing the number of stops. Finally, the simulation is executed to analyze the performance of the model by comparing it to other models, and the superiority of the LGLR model is evident in terms of delay, number of stops, queue length, and overall performance in the saturated HGRN.

Decentralized Spatial Decomposition for Traffic Signal Synchronization

The Traffic Signal Synchronization is a traffic engineering technique of matching the green light times for a series of intersections to enable the maximum number of vehicles to pass through, thereby reducing stops and delays experienced by motorists. Synchronizing Traffic Signals ensures a better flow of traffic and minimizes gas consumption and pollutant emissions. In this paper we provide a solution to the the traffic signals problem via simulation. The objective function used in this work is a weighted sum of the delays caused by the signalized intersections, and it is calculated by platoon model. Urban signal timing is a non-convex problem and finding an optimal solution for not very small and simple networks may take long time, wherever possible. For this reason we proposed a spatial decomposition of the network, it is obtained by the distributed consensus algorithms. In this paper we provide a distributed communication architecture for a network of smart traffic lights. Each semaphore shares information in a fully distributed way, only with its neighbors according to the topology of the communication network, hence avoiding to resort to a central authority. Given the subnetwork a surrogate method is applied to solve the Traffic Signal Synchronization problem.

A linear programming approach for adaptive synchronization of traffic signals

AbstractAs traffic congestion during rush hours is a growing problem for most cities, there is an increasing need for more effective management of traffic signal control and traffic assignment systems. We present here a new adaptive system based on a linear programming model for the signal‐control problem. The objective is to minimize the total length of the queues of vehicles waiting at each intersection. The model is based on traffic information provided by real‐time sensors installed at each intersection. In order to compare the performance of our program with the current scheduling designed by the transit office of Buenos Aires city, we used a traffic simulation system and real traffic flow data of two pilot areas of the city. Preliminary results are very promising.

A Global Optimization Approach to Solve the Traffic Signal Synchronization Problem

The Traffic Signal Synchronization is a traffic engineering technique of matching the green light times for a series of intersections to enable the maximum number of vehicles to pass through, thereby reducing stops and delays experienced by motorists. Synchronizing traffic signals ensures a better flow of traffic and minimizes gas consumption and pollutant emissions. The objective function used in this work is a weighted sum of the delays caused by the signalized intersections. In this paper, we apply generalized’surrogate problem’ methodology that is based on an on-line control scheme which transforms the problem into a’surrogate’ continuous optimization problem and proceeds to solve the latter using standard gradient-based approaches while simultaneously updating both actual and surrogate system states. We extend a ‘surrogate problem’ approach that is developed for a class of stochastic discrete optimization problems so as to tackle the traffic signal synchronization problem to minimize the total delay (DTSS). Numerical experiments conducted on a test and a real networks show that the surrogate method converges in a very small area.

Synchronization of Traffic Signals “A Case Study – Eastern Ring Road, Indore”

During the past decade major cities have under gone haphazard growth of Industrialization, urbanization of country. Consequently the urban population has to travel greater distances within minimum possible time. To manage travel demand the intersection should be give least resistance to traffic flow so that the travel time can be minimized. The present requirement of metropolitan cities is to absorb the growing traffic demand but within the same physical dimension at the intersection. These days all around the globe efforts are being put forward to protect the environment to save earth. In this paper an attempt has been made to study the various intersections, so as to minimize the delays at these intersections and consequently improve the level service. Traffic signal can be synchronized so that a vehicle starting at one end of the Street and traveling at Preassigned speed can go to other end without stopping for red light. At each intersection the existing traffic has been estimated and then signal designed. Improve the level of service at intersections and to minimize delay, optimized signal has been synchronize and estimated the benefits.

Synchronization of traffic signals as a means of reducing red-light running.

The goal of this study was to determine if traffic signals that are synchronized along a route are associated with fewer red-light violations than traffic signals that are not synchronized. A total 3600 cycles of traffic signals at 12 intersections along 2 major urban arteries were observed. Synchronized intersections were effective in reducing the likelihood of red-light running (RLR) by (a) providing fewer opportunities than nonsynchronized intersections for RLR and (b) having a lower rate of RLR relative to the number of opportunities. After adjustment for the number of opportunities, the odds of entering the intersections in red in synchronized intersections were nearly 1/7 the odds of RLR in nonsynchronized intersections. Congestion reduced the effectiveness of synchronized intersections relative to nonsynchronized intersections. Male drivers were slightly more likely to run red lights than female drivers, and the effects of synchronization were fairly constant across age, gender, and the presence or absence of passengers. Actual or potential applications of this research involve signal synchronization to reduce aggressive driving in general and RLR in particular.

IFORS' Operational Research Hall of Fame John D. C. Little

International Transactions in Operational ResearchVolume 11, Issue 3 p. 361-364 Free Access IFORS' Operational Research Hall of Fame John D. C. Little Richard C. Larson, Richard C. LarsonSearch for more papers by this author Richard C. Larson, Richard C. LarsonSearch for more papers by this author First published: 05 May 2004 https://doi.org/10.1111/j.1475-3995.2004.00463.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Selected original works Little, J.D.C., 1961. A Proof for the Queuing Formula: L=λW. Operations Research, 9, 383– 7. Little, J.D.C., Murty, K.G., Sweeney, D.W., Karel, C., 1963. An Algorithm for the Traveling Salesman Problem. Operations Research, 11, 972– 89. Little, J.D.C., 1966. The Synchronization of Traffic Signals by Mixed-Integer Linear Programming. Operations Research, 14, 568– 94. Little, J.D.C., 1966. A Model of Adaptive Control of Promotional Spending. Operations Research, 14, 1075– 98. Little, J.D.C., Lodish, L., 1969. A Media Planning Calculus. Operations Research, 17, 1– 35. Little, J.D.C., 1970. Managers and Models: The Concept of a Decision Calculus. Management Science, 16, B466– 85. Little, J.D.C., 1979. Decision Support Systems for Marketing Managers. Journal of Marketing, 43(3), 9– 26. Little, J.D.C., Cohen, S., 1982. The MAXBAND Program for Arterial Signal Timing Plans. Public Roads, 46(2), 61– 5. Guadagni, P.M., Little, L.D.C., 1983. A Logit Model of Brand Choice Calibrated on Scanner Data. Marketing Science, 2, 203–238. Little, J.D.C., 1998. Integrated Measures of Sales, Merchandising, and Distribution. International Journal of Research in Marketing, 15, 473– 85. Little, J.D.C., 2002. Philip M. Morse and the Beginnings. Operations Research, 50, 146– 8. Citing Literature Volume11, Issue3May 2004Pages 361-364 ReferencesRelatedInformation

Traffic signal synchronization.

The benefits of traffic signal synchronization are examined within the cellular automata approach. The microsimulations of traffic flow are obtained with different settings of signal period T and time delay delta. Both numerical results and analytical approximations are presented. For undersaturated traffic, the green-light wave solutions can be realized. For saturated traffic, the correlation among the traffic signals has no effect on the throughput. For oversaturated traffic, the benefits of synchronization are manifest only when stochastic noise is suppressed.

A restricted branch-and-bound approach for generating maximum bandwidth signal timing plans for traffic networks

The synchronization of traffic signals located along the urban/suburban arterials in metropolitan areas is perhaps one of the most cost-effective methods for improving traffic flow along these streets. The main objective of synchronized signal timing is to keep traffic moving in platoons throughout the signal controlled system, by setting the signals along the arterials/networks to provide maximum bandwidth progression. A popular technique for generating signal timing plans formulates the problem as a mixed-integer linear program and uses the Land and Powell branch-and-bound search technique to arrive at the optimal solution. Due to numerical instability of the solution technique and the exhaustive nature of the search procedure, the current implementation tends to be computationally inefficient and infeasable for realistic network problems. Furthermore, numerical instability results in suboptimal or no solutions for network problems with a range of variable cycle times. This paper presents the development of a fast and numerically stable heuristic for the maximum bandwidth signal setting problem. The heuristic is computationally efficient, can generate optimal/near-optimal solutions, and is implemented on a PC. It is based on restricted search of the integer variables in the solution space. The efficiency of this heuristic is supported by computational results for a number of test problems. 1998 Elsevier Science Ltd. All rights reserved

Synchronization of Traffic Signals in Grid Networks

A method of synchronizing traffic signals interconnected in an arbitrary network is presented. The procedure consists of using a simplified mathematical model for traffic to relate the vehicular delay within the network to the signal parameters and then searching over these parameters to minimize the delay. The technique has been used to synchronize traffic signals in San Jose, California and has yielded a ten percent reduction in the average delay per car in comparison with the signal settings determined by the city traffic department with conventional engineering methods.

The Synchronization of Traffic Signals for Minimum Delay

In order to ascertain whether neighboring intersections can be effectively coupled on the basis of traffic behavior, observational information on vehicular platoons was collected at four sites in London, England. This information is analyzed with particular emphasis on the phasing or synchronization of neighboring intersections for minimum delay. At each of the four sites studied, arrival time data was collected at four positions downstream from the signalized intersection from which the vehicular platoons were emerging. This data gives a measure of how platoons diffuse as they move from one intersection to the next. The analysis indicates that the diffusion process can be taken into account in the setting of signals. In particular, total delay in vehicle-hours per hour of green as a function of offset time is calculated, and in turn, the optimal offset time that would minimize delay is shown to be a linear function of the distance from the issuing traffic signal.

The Synchronization of Traffic Signals by Mixed-Integer Linear Programming

Traffic signals can be synchronized so that a car, starting at one end of a main artery and traveling at preassigned speeds, can go to the other end without stopping for a red light. The portion of a signal cycle for which this is possible is called the bandwidth for that direction. A mixed-integer linear program is formulated for the following arterial problem: Given (1) an arbitrary number of signals, (2) the red-green split at each signal, (3) upper and lower limits on signal period, (4) upper and lower limits on speed between adjacent signals, and (5) limits on change in speed, find (1) common signal period, (2) speeds between signals, and (3) the relative phasing of the signals, in order to maximize the sum of the bandwidths for the two directions. Several variants of the problem are formulated, including the problem of synchronizing a network of signals. Branch-and-bound algorithms are developed for solving the mixed-integer linear programs by solving sequences of ordinary linear programs. A 10-signal arterial example and a 7-signal network example are worked out.