A Survey on Urban Traffic Management System Using Wireless Sensor Networks
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paper_title: A User-Customizable Urban Traffic Information Collection Method Based on Wireless Sensor Networks

paper_content:

Traffic monitoring can efficiently promote urban planning and encourage better use of public transport. Efficient traffic information collection is one important part of traffic monitoring systems. Based on a technique using wireless sensor networks (WSNs), this paper provides a flexible framework for regional traffic information collection in accordance with user request. This framework serves as a basis for future research in designing and implementing traffic monitoring applications. A two-layer network architecture is established for traffic information acquisition in the context of a WSN environment. In addition, a user-customizable data-centric routing scheme is proposed for traffic information delivery, in which multiple routing-related information is considered for decision-making to meet different user requirements. Simulations have shown good performance of the proposed routing scheme compared with other traditional routing schemes on a real-world urban traffic network.
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paper_title: Efficient Data Propagation in Traffic-Monitoring Vehicular Networks

paper_content:

Road congestion and traffic-related pollution have a large negative social and economic impact on several economies worldwide. We believe that investment in the monitoring, distribution, and processing of traffic information should enable better strategic planning and encourage better use of public transport, both of which would help cut pollution and congestion. This paper investigates the problem of efficiently collecting and disseminating traffic information in an urban setting. We formulate the traffic data acquisition problem and explore solutions in the mobile sensor network domain while considering realistic application requirements. By leveraging existing infrastructure such as traveling vehicles in the city, we propose traffic data dissemination schemes that operate on both the routing and the application layer; our schemes are frugal in the use of the wireless medium, rendering our system interoperable with the proliferation of competing applications. We introduce the following two routing algorithms for vehicular networks that aim at minimizing communication and, at the same time, adhering to a delay threshold set by the application: 1) delay-bounded greedy forwarding and 2) delay-bounded minimum-cost forwarding. We propose a framework that jointly optimizes the two key processes associated with monitoring traffic, i.e., data acquisition and data delivery, and provide a thorough experimental evaluation based on realistic vehicular traces on a real city map.
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paper_title: Reducing Traffic Jams via VANETs

paper_content:

A transition from free flow to congested traffic on highways often spontaneously originates, despite the fact that the road could satisfy a higher traffic demand. The reasons for such a traffic breakdown are perturbations caused by human drivers in dense traffic. We present a strategy to reduce traffic congestion with the help of vehicle-to-vehicle communication. Periodically emitted beacons are used to analyze traffic flow and to warn other drivers of a possible traffic breakdown. Drivers who receive such a warning are told to keep a larger gap to their predecessor. By doing so, they are less likely to be the source of perturbations, which can cause a traffic breakdown. We analyze the proposed strategy via computer simulations and investigate which fraction of communicating vehicles is necessary until a beneficial influence on traffic flow is observable. We show that penetration rates of 10% and less can have significant influence on traffic flow and travel times. In addition to applying a realistic mobility model, we further increase the degree of realism by the use of empirical traffic data from loop detectors on a German Autobahn.
---
paper_title: A model for traffic control in urban environments

paper_content:

Wireless technologies can help solve traffic congestions in urban environments, where road infrastructures develop slower than the sometimes exponential growth in the number of cars in traffic. We present a model for traffic control and congestion avoidance developed over a vehicular ad-hoc network created between the cars in traffic and the road infrastructure. We propose a solution for monitoring traffic using not only sensors within the road infrastructure, but also the cars themselves acting as data collectors. The traffic control decision, provided by the road infrastructure, is scalable, load-balanced, and based on correction decisions for the route adjustment based on local areas. We present evaluation results that show the capabilities of the proposed congestion avoidance model.
---
paper_title: A vehicle-logo location approach based on edge detection and projection

paper_content:

Vehicle-logo location is an essential part of vehicle-logo recognition system. In this paper, a new method of vehicle-logo location is proposed. Firstly, the approximate region of vehicle-logo is obtained through the position of vehicle-plate. Then, we judge the texture of vehicle-logo background either horizontal or vertical with the edge detection and projection approach. Finally, with the known texture, position of the vehicle-logo can be located correctly by morphological filter and projection information. Experimental results demonstrate the proposed method is effective.
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paper_title: Instrumentation for safe vehicular flow in intelligent traffic control systems using wireless networks

paper_content:

This paper describes a ZigBee based wireless system to assists traffic flow on arterial urban roads. Real-time simulation in laboratory environment is conducted to determine the traffic throughput to avoid possible congestions or ease existing congestions. Random numbers are generated to mimic approaching traffic, and this information is shared by a ZigBeebased real-time wirelessly network. Wireless nodes are connected to different PLCs representing different traffic lights in a cluster. Once the information is shared the timing and sequencing decisions are taken collectively in a synchronized manner. In this paper, the information is displayed on SCADA connected to each PLC for viewing the characteristics of continuous vehicular flow. It is found that the topology of the network can play an important role in the throughput of data, which may be critical in safety critical operations such as the control of traffic lights. This paper aims to highlight some of the possible effects of dataflow flow and time-delays faced by modern intelligent control of traffic lights.
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paper_title: Real time evaluation of shortest remaining processing time based schedulers for traffic congestion control using wireless sensor networks

paper_content:

Pre-timed traffic signals are inefficient in optimizing the traffic flow throughout the day, resulting in greater waiting times at the intersections particularly in congested urban areas during peak hours. Traffic actuated signals use real time traffic data obtained from sensors at the intersections to service queues intelligently. We developed a test bed for the real time evaluation of adaptive traffic light control algorithms using the microscopic traffic simulation open source software, SUMO (Simulation of Urban Mobility), and the AVR 32-bit microcontroller. An interface was developed between SUMO and the AVR microcontroller in which we used the simulation data generated by SUMO as an input to the microcontroller which executed the scheduling algorithms and sent commands back to SUMO for changing the states of the traffic signals accordingly. We implemented four scheduling algorithms in SUMO through the AVR microcontroller, the effect of the algorithms on the traffic network was studied using SUMO and execution times of the scheduling algorithms were measured using the AVR microcontroller. Through this interface, scheduling algorithms can be evaluated more effectively and accurately as compared to the case in which the algorithms are fed with data using pseudo random number generators.
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paper_title: A Study on Vehicle Detection and Tracking Using Wireless Sensor Networks

paper_content:

Wireless Sensor network (WSN) is an emerging technology and has great potential to be employed in critical situations. The development of wireless sensor networks was originally motivated by military applications like battlefield surveillance. However, Wireless Sensor Networks are also used in many areas such as Industrial, Civilian, Health, Habitat Monitoring, Environmental, Military, Home and Office application areas. Detection and tracking of targets (eg. animal, vehicle) as it moves through a sensor network has become an increasingly important application for sensor networks. The key advantage of WSN is that the network can be deployed on the fly and can operate unattended, without the need for any pre-existing infrastructure and with little maintenance. The system will estimate and track the target based on the spatial differences of the target signal strength detected by the sensors at different locations. Magnetic and acoustic sensors and the signals captured by these sensors are of present interest in the study. The system is made up of three components for detecting and tracking the moving objects. The first component consists of inexpensive off-the shelf wireless sensor devices, such as MicaZ motes, capable of measuring acoustic and magnetic signals generated by vehicles. The second component is responsible for the data aggregation. The third component of the system is responsible for data fusion algorithms. This paper inspects the sensors available in the market and its strengths and weakness and also some of the vehicle detection and tracking algorithms and their classification. This work focuses the overview of each algorithm for detection and tracking and compares them based on evaluation parameters.
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paper_title: Wireless Sensor Networks for Oceanographic Monitoring: A Systematic Review

paper_content:

Monitoring of the marine environment has come to be a field of scientific interest in the last ten years. The instruments used in this work have ranged from small-scale sensor networks to complex observation systems. Among small-scale networks, Wireless Sensor Networks (WSNs) are a highly attractive solution in that they are easy to deploy, operate and dismantle and are relatively inexpensive. The aim of this paper is to identify, appraise, select and synthesize all high quality research evidence relevant to the use of WSNs in oceanographic monitoring. The literature is systematically reviewed to offer an overview of the present state of this field of study and identify the principal resources that have been used to implement networks of this kind. Finally, this article details the challenges and difficulties that have to be overcome if these networks are to be successfully deployed.
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paper_title: A User-Customizable Urban Traffic Information Collection Method Based on Wireless Sensor Networks

paper_content:

Traffic monitoring can efficiently promote urban planning and encourage better use of public transport. Efficient traffic information collection is one important part of traffic monitoring systems. Based on a technique using wireless sensor networks (WSNs), this paper provides a flexible framework for regional traffic information collection in accordance with user request. This framework serves as a basis for future research in designing and implementing traffic monitoring applications. A two-layer network architecture is established for traffic information acquisition in the context of a WSN environment. In addition, a user-customizable data-centric routing scheme is proposed for traffic information delivery, in which multiple routing-related information is considered for decision-making to meet different user requirements. Simulations have shown good performance of the proposed routing scheme compared with other traditional routing schemes on a real-world urban traffic network.
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paper_title: Robust and efficient data collection schemes for vehicular multimedia sensor Networks

paper_content:

In vehicular multimedia sensor networks vehicles are equipped with cameras and they continuously capture images from urban streets. Then, vehicles can use roadside wireless access points encountered during travel to deliver recorded image data to remote data collectors, in which the information from several multimedia streams is aggregated and processed to enable new services, such as urban surveillance, or traffic and road monitoring. However, due to constraints on the wireless access network the amount of image data that can be transferred from vehicles is limited, and data redundancy should be avoided. In this paper we address this issue by using submodular optimization techniques to develop an efficient data collection algorithm capable of providing data redundancy elimination under network capacity constraints. We also design an alternative decentralized scheme that operates on longer time scales and relies only on basic aggregate information. We use network simulations with realistic vehicular mobility patterns to verify the performance gains of our proposed schemes compared to a baseline system that ignores data redundancy. Simulation results show that our data collection techniques can ensure a more accurate coverage of the road network while significantly reducing the amount of transferred data.
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paper_title: Feasibility of deploying wireless sensor based road side solutions for Intelligent Transportation Systems

paper_content:

The effectiveness of Intelligent Transportation Systems depends on the accuracy and timely reliable provisioning of real time data supplied by traffic data collection mechanisms. Data collection through wireless sensor networks is a very effective approach due to their easy installation, low cost, processing capabilities, small size, flexibility, and wireless communication capabilities. WSN are used in ITS for smart parking lots, adaptive traffic light control, accident avoidance and traffic estimation etc. In this paper we propose a WSN based road side communication architecture and system that can be utilized for the intelligent control and management of vehicular traffic at road intersections. In the proposed architecture, the end nodes are carried by vehicles that communicate with road side units, which in turn send the data to the coordinator module at the intersection. We introduce a reliable and robust channel switching technique that reduces the response time, energy consumption and connectivity delay while increasing the reliability of packet delivery. We perform sensitivity analysis of the proposed system architecture by varying various communication parameters to determine optimum system configuration. The results prove the integrity and feasibility of the deployment of our proposed architecture.
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paper_title: Dissemination and Harvesting of Urban Data Using Vehicular Sensing Platforms

paper_content:

Recent advances in vehicular communications make it possible to realize vehicular sensor networks, i.e., collaborative environments where mobile vehicles that are equipped with sensors of different nature (from toxic detectors to still/video cameras) interwork to implement monitoring applications. In particular, there is an increasing interest in proactive urban monitoring, where vehicles continuously sense events from urban streets, autonomously process sensed data (e.g., recognizing license plates), and, possibly, route messages to vehicles in their vicinity to achieve a common goal (e.g., to allow police agents to track the movements of specified cars). This challenging environment requires novel solutions with respect to those of more-traditional wireless sensor nodes. In fact, unlike conventional sensor nodes, vehicles exhibit constrained mobility, have no strict limits on processing power and storage capabilities, and host sensors that may generate sheer amounts of data, thus making already-known solutions for sensor network data reporting inapplicable. This paper describes MobEyes, which is an effective middleware that was specifically designed for proactive urban monitoring and exploits node mobility to opportunistically diffuse sensed data summaries among neighbor vehicles and to create a low-cost index to query monitoring data. We have thoroughly validated the original MobEyes protocols and demonstrated their effectiveness in terms of indexing completeness, harvesting time, and overhead. In particular, this paper includes (1) analytic models for MobEyes protocol performance and their consistency with simulation-based results, (2) evaluation of performance as a function of vehicle mobility, (3) effects of concurrent exploitation of multiple harvesting agents with single/multihop communications, (4) evaluation of network overhead and overall system stability, and (5) performance validation of MobEyes in a challenging urban tracking application where the police reconstruct the movements of a suspicious driver, e.g., by specifying the license number of a car.
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paper_title: Delay-optimal data forwarding in Vehicular Sensor Networks

paper_content:

The vehicular sensor network (VSN) is emerging as a new solution for monitoring urban environments such as intelligent transportation systems and air pollution. One of the crucial factors that determine the service quality of urban monitoring applications is the delivery delay of sensing data packets in the VSN. In this paper, we study the problem of routing data packets with minimum delay in the VSN by exploiting 1) vehicle traffic statistics, 2) anycast routing, and 3) knowledge of future trajectories of vehicles such as busses. We first introduce a novel road network graph model that incorporates the three factors into the routing metric. We then characterize the packet delay on each edge as a function of the vehicle density, speed, and the length of the edge. Based on the network model and delay function, we formulate the packet routing problem as a Markov decision process (MDP) and develop an optimal routing policy by solving the MDP. Evaluations using real vehicle traces in a city show that our routing policy significantly improves the delay performance compared with existing routing protocols. Specifically, optimal VSN data forwarding (OVDF) yields, on average, 96% better delivery ratio and 72% less delivery delay than existing algorithms in some areas distant from destinations.
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paper_title: Traffic control system using wireless sensor network

paper_content:

The Real time locating system (RTLS) determines and tracks the location of assets and people. This paper presents a novel application to estimate the position and velocity of vehicle using wireless sensor network. Two Anchor nodes are used as reader along roadside and total distance between them is known. Whenever a moving vehicle with tag comes in between the common part of the operating range of two anchor nodes, exchange of information is done using Symmetric double sided two way ranging algorithm, which gives us position information. Using position information at several interval of time, velocity can be easily obtained. Position and velocity is obtained and displayed on base station. Kalman filtering is used to estimate the position and velocity from noisy measurements. Performance evaluation is done comparing vehicle position speed true values with experimental and estimated values.
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paper_title: Vehicular Traffic Monitoring Using Bluetooth Scanning Over a Wireless Sensor Network

paper_content:

The ubiquitous nature of Bluetooth equipped devices has made it opportunistic to scavenge information that can be repurposed for applications other than initially intended. One such opportunity is in vehicular traffic monitoring, whereby sampling of Bluetooth radios serve as proxies for vehicles and consequently for traffic density and flow. This paper discusses a complete data collection system developed at the University of Manitoba that utilizes a variety of wireless networking technologies and devices to collect inferred traffic data at an intersection along a major thoroughfare in an urban setting. Specifically, a wireless sensor network of slave probes was designed and implemented with the objective to collect Bluetooth device information for this purpose. To facilitate easy setup and a long battery life, a solar-powered probe design was investigated. Data from each slave probe is communicated to a master node through XBee communication, where it is stored on a secure digital (SD) memory card before being transmitted to a central server every five minutes over a global system for mobile communications (GSM) cellular network. The server parses the data received and stores it in a database. Consumer and corporate websites may then access this database to display archived data or current data in real-time to various users.
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paper_title: An Intelligent Traffic Flow Control System Based on Radio Frequency Identification and Wireless Sensor Networks

paper_content:

This study primarily focuses on the use of radio frequency identification (RFID) as a form of traffic flow detection, which transmits collected information related to traffic flow directly to a control system through an RS232 interface. At the same time, the sensor analyzes and judges the information using an extension algorithm designed to achieve the objective of controlling the flow of traffic. In addition, the traffic flow situation is also transmitted to a remote monitoring control system through ZigBee wireless network communication technology. The traffic flow control system developed in this study can perform remote transmission and reduce traffic accidents. And it can also effectively control traffic flow while reducing traffic delay time and maintaining the smooth flow of traffic.
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paper_title: Using DTMon to monitor transient flow traffic

paper_content:

We evaluate the performance of the DTMon dynamic traffic monitoring system to measure travel times and speeds in transient flow traffic caused by non-recurring congestion. DTMon uses vehicular networks and roadside infrastructure to collect data from passing vehicles. We show DTMon's ability to gather high-quality real-time traffic data such as travel time and speed. These metrics can be used to detect transitions in traffic flow (e.g., caused by congestion) especially where accurate flow rate information is not available. We evaluate the accuracy and latency of DTMon in providing traffic measurements using two different methods of message delivery. We show the advantages of using dynamically-defined measurement points for monitoring transient flow traffic. We compare DTMon with currently in-use probe-based systems (e.g., AVL) and fixed-point sensors and detectors (e.g., ILD).
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paper_title: Monitoring free flow traffic using vehicular networks

paper_content:

We present DTMon, a dynamic traffic monitiroing system using vehicular networks, and analyze its performance in free flow (i.e., non-congested) traffic. DTMon uses roadside infrastructure to gather and report current traffic conditions to traffic management centers and equipped vehicles. We analyze how traffic characteristics such as speed, flow rate, percentage of communicating vehicles, and distance from the DTMon measurement point to the roadside infrastructure affects the amount and quality of data that can be gathered and delivered. We evaluate five different methods of delivering data from vehicles to the roadside infrastructure, including pure vehicle-to-vehicle communication, store-and-carry, and hybrid methods. Methods that employ some amount of store-and-carry can increase the delivery rate, but also increase the message delay. We show that with just a few pieces of roadside infrastructure, DTMon can gather high-quality travel time and speed data even with a low percentage of communicating vehicles.
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paper_title: Vehicle-to-vehicle and vehicle-to-roadside multi-hop communications for vehicular sensor networks: Simulations and field trial

paper_content:

Using vehicles as sensors for traffic and environment monitoring is a new paradigm that opens the way to worthwhile applications. Data collected on board are usually delivered through the cellular network, with the consequent overloading risk. This paper focuses on the alternative adoption of short range vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications, with particular reference to the wireless access in vehicular environment (WAVE)/IEEE802.11p technology. Specifically, we propose and validate, through simulations in a urban scenario, a simple but effective routing algorithm to forward data through V2V and V2R communications. The benefits are quantified in terms of the amount of data that can be transmitted without using cellular resources. Furthermore, we present an urban field trial, deployed to test our proposed multi-hop algorithm, through the adoption of low cost hardware and open source software.
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paper_title: A vehicle-logo location approach based on edge detection and projection

paper_content:

Vehicle-logo location is an essential part of vehicle-logo recognition system. In this paper, a new method of vehicle-logo location is proposed. Firstly, the approximate region of vehicle-logo is obtained through the position of vehicle-plate. Then, we judge the texture of vehicle-logo background either horizontal or vertical with the edge detection and projection approach. Finally, with the known texture, position of the vehicle-logo can be located correctly by morphological filter and projection information. Experimental results demonstrate the proposed method is effective.
---
paper_title: Low Energy and Low Latency in Wireless Sensor Networks

paper_content:

It is widely known that in wireless sensor networks (WSN), energy efficiency is of utmost importance. As a result, a common protocol design guideline has been to trade off some performance metrics such as throughput and delay for energy. This has also gone well in line with many applications for WSN. However, there are other applications with real-time constraints, such as those involved in surveillance or control loops, for which WSN still need to be energy efficient but also need to provide better performance, particularly latency. This paper presents a WSN cross-layer design approach involving the physical, MAC, and network layers that not only preserves the energy efficiency of current alternatives but also coordinates the transfer of packets from source to destination in such a way that latency and jitter are improved considerably. Our simulations show how LEMR (Latency, Energy, MAC and Routing), the proposed protocol, outperforms the well-known TMAC and S-MAC protocols in both performance metrics.
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paper_title: Using GPS Data to Gain Insight into Public Transport Travel Time Variability

paper_content:

Transit service reliability is an important determinant of service quality, which has been mainly studied from the perspective of passengers waiting at stops. Day-to-day variability of travel time also deteriorates service reliability, but is not a well-researched area in the literature partly due to the lack of comprehensive data sets on bus travel times. While this problem is now being addressed through the uptake of global positioning system (GPS)-based tracking systems, methodologies to analyze these data sets are limited. This paper addresses this issue by investigating day-to-day variability in public transport travel time using a GPS data set for a bus route in Melbourne, Australia. It explores the nature and shape of travel time distributions for different departure time windows at different times of the day. Factors causing travel time variability of public transport are also explored using a linear regression analysis. The results show that in narrower departure time windows, travel time distributions are best characterized by normal distributions. For wider departure time windows, peak-hour travel times follow normal distributions, while off-peak travel times follow lognormal distributions. The factors contributing to the variability of travel times are found to be land use, route length, number of traffic signals, number of bus stops, and departure delay relative to the scheduled departure time. Travel time variability is higher in the AM peak and lower in the off-peak. The impact of rainfall on travel time variability is only found significant in the AM peak. While the paper presents new methods for analyzing GPS-based data, there is much scope for expanding knowledge through wider applications to new data sets and using a wider range of explanatory variables.
---
paper_title: Delay-optimal data forwarding in Vehicular Sensor Networks

paper_content:

The vehicular sensor network (VSN) is emerging as a new solution for monitoring urban environments such as intelligent transportation systems and air pollution. One of the crucial factors that determine the service quality of urban monitoring applications is the delivery delay of sensing data packets in the VSN. In this paper, we study the problem of routing data packets with minimum delay in the VSN by exploiting 1) vehicle traffic statistics, 2) anycast routing, and 3) knowledge of future trajectories of vehicles such as busses. We first introduce a novel road network graph model that incorporates the three factors into the routing metric. We then characterize the packet delay on each edge as a function of the vehicle density, speed, and the length of the edge. Based on the network model and delay function, we formulate the packet routing problem as a Markov decision process (MDP) and develop an optimal routing policy by solving the MDP. Evaluations using real vehicle traces in a city show that our routing policy significantly improves the delay performance compared with existing routing protocols. Specifically, optimal VSN data forwarding (OVDF) yields, on average, 96% better delivery ratio and 72% less delivery delay than existing algorithms in some areas distant from destinations.
---
paper_title: Vehicular Traffic Monitoring Using Bluetooth Scanning Over a Wireless Sensor Network

paper_content:

The ubiquitous nature of Bluetooth equipped devices has made it opportunistic to scavenge information that can be repurposed for applications other than initially intended. One such opportunity is in vehicular traffic monitoring, whereby sampling of Bluetooth radios serve as proxies for vehicles and consequently for traffic density and flow. This paper discusses a complete data collection system developed at the University of Manitoba that utilizes a variety of wireless networking technologies and devices to collect inferred traffic data at an intersection along a major thoroughfare in an urban setting. Specifically, a wireless sensor network of slave probes was designed and implemented with the objective to collect Bluetooth device information for this purpose. To facilitate easy setup and a long battery life, a solar-powered probe design was investigated. Data from each slave probe is communicated to a master node through XBee communication, where it is stored on a secure digital (SD) memory card before being transmitted to a central server every five minutes over a global system for mobile communications (GSM) cellular network. The server parses the data received and stores it in a database. Consumer and corporate websites may then access this database to display archived data or current data in real-time to various users.
---
paper_title: Using DTMon to monitor transient flow traffic

paper_content:

We evaluate the performance of the DTMon dynamic traffic monitoring system to measure travel times and speeds in transient flow traffic caused by non-recurring congestion. DTMon uses vehicular networks and roadside infrastructure to collect data from passing vehicles. We show DTMon's ability to gather high-quality real-time traffic data such as travel time and speed. These metrics can be used to detect transitions in traffic flow (e.g., caused by congestion) especially where accurate flow rate information is not available. We evaluate the accuracy and latency of DTMon in providing traffic measurements using two different methods of message delivery. We show the advantages of using dynamically-defined measurement points for monitoring transient flow traffic. We compare DTMon with currently in-use probe-based systems (e.g., AVL) and fixed-point sensors and detectors (e.g., ILD).
---
paper_title: Low Energy and Low Latency in Wireless Sensor Networks

paper_content:

It is widely known that in wireless sensor networks (WSN), energy efficiency is of utmost importance. As a result, a common protocol design guideline has been to trade off some performance metrics such as throughput and delay for energy. This has also gone well in line with many applications for WSN. However, there are other applications with real-time constraints, such as those involved in surveillance or control loops, for which WSN still need to be energy efficient but also need to provide better performance, particularly latency. This paper presents a WSN cross-layer design approach involving the physical, MAC, and network layers that not only preserves the energy efficiency of current alternatives but also coordinates the transfer of packets from source to destination in such a way that latency and jitter are improved considerably. Our simulations show how LEMR (Latency, Energy, MAC and Routing), the proposed protocol, outperforms the well-known TMAC and S-MAC protocols in both performance metrics.
---
paper_title: Using GPS Data to Gain Insight into Public Transport Travel Time Variability

paper_content:

Transit service reliability is an important determinant of service quality, which has been mainly studied from the perspective of passengers waiting at stops. Day-to-day variability of travel time also deteriorates service reliability, but is not a well-researched area in the literature partly due to the lack of comprehensive data sets on bus travel times. While this problem is now being addressed through the uptake of global positioning system (GPS)-based tracking systems, methodologies to analyze these data sets are limited. This paper addresses this issue by investigating day-to-day variability in public transport travel time using a GPS data set for a bus route in Melbourne, Australia. It explores the nature and shape of travel time distributions for different departure time windows at different times of the day. Factors causing travel time variability of public transport are also explored using a linear regression analysis. The results show that in narrower departure time windows, travel time distributions are best characterized by normal distributions. For wider departure time windows, peak-hour travel times follow normal distributions, while off-peak travel times follow lognormal distributions. The factors contributing to the variability of travel times are found to be land use, route length, number of traffic signals, number of bus stops, and departure delay relative to the scheduled departure time. Travel time variability is higher in the AM peak and lower in the off-peak. The impact of rainfall on travel time variability is only found significant in the AM peak. While the paper presents new methods for analyzing GPS-based data, there is much scope for expanding knowledge through wider applications to new data sets and using a wider range of explanatory variables.
---
paper_title: Reducing Traffic Jams via VANETs

paper_content:

A transition from free flow to congested traffic on highways often spontaneously originates, despite the fact that the road could satisfy a higher traffic demand. The reasons for such a traffic breakdown are perturbations caused by human drivers in dense traffic. We present a strategy to reduce traffic congestion with the help of vehicle-to-vehicle communication. Periodically emitted beacons are used to analyze traffic flow and to warn other drivers of a possible traffic breakdown. Drivers who receive such a warning are told to keep a larger gap to their predecessor. By doing so, they are less likely to be the source of perturbations, which can cause a traffic breakdown. We analyze the proposed strategy via computer simulations and investigate which fraction of communicating vehicles is necessary until a beneficial influence on traffic flow is observable. We show that penetration rates of 10% and less can have significant influence on traffic flow and travel times. In addition to applying a realistic mobility model, we further increase the degree of realism by the use of empirical traffic data from loop detectors on a German Autobahn.
---
paper_title: A model for traffic control in urban environments

paper_content:

Wireless technologies can help solve traffic congestions in urban environments, where road infrastructures develop slower than the sometimes exponential growth in the number of cars in traffic. We present a model for traffic control and congestion avoidance developed over a vehicular ad-hoc network created between the cars in traffic and the road infrastructure. We propose a solution for monitoring traffic using not only sensors within the road infrastructure, but also the cars themselves acting as data collectors. The traffic control decision, provided by the road infrastructure, is scalable, load-balanced, and based on correction decisions for the route adjustment based on local areas. We present evaluation results that show the capabilities of the proposed congestion avoidance model.
---
paper_title: Effective Urban Traffic Monitoring by Vehicular Sensor Networks

paper_content:

Traffic monitoring in urban transportation systems can be carried out based on vehicular sensor networks. Probe vehicles (PVs), such as taxis and buses, and floating cars (FCs), such as patrol cars for surveillance, can act as mobile sensors for sensing the urban traffic and send the reports to a traffic-monitoring center (TMC) for traffic estimation. In the TMC, sensing reports are aggregated to form a traffic matrix, which is used to extract traffic information. Since the sensing vehicles cannot cover all the roads all the time, the TMC needs to estimate the unsampled data in the traffic matrix. As this matrix can be approximated to be of low rank, matrix completion (MC) is an effective method to estimate the unsampled data. However, our previous analysis on the real traces of taxis in Shanghai reveals that MC methods do not work well due to the uneven samples of PVs, which is common in urban traffic. To exploit the intrinsic relationship between the unevenness of samples and traffic estimation error, we study the temporal and spatial entropies of samples and successfully define the important criterion, i.e., average entropy of the sampling process. A new sampling rule based on this relationship is proposed to improve the performance of estimation and monitoring. With the sampling rule, two new patrol algorithms are introduced to plan the paths of controllable FCs to proactively participate in traffic monitoring. By utilizing the patrol algorithms for real-data-set analysis, the estimation error reduces from 35% to about 10%, compared with the random patrol or interpolation method in traffic estimation. Both the validity of the exploited relationship and the effectiveness of the proposed patrol control algorithms are demonstrated.
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paper_title: Mobility management algorithms and applications for mobile sensor networks

paper_content:

Wireless sensor networks (WSNs) offer a convenient way to monitor physical environments. In the past, WSNs are all considered static to continuously collect information from the environment. Today, by introducing intentional mobility to WSNs, we can further improve the network capability on many aspects, such as automatic node deployment, flexible topology adjustment, and rapid event reaction. In this paper, we survey recent progress in mobile WSNs and compare works in this field in terms of their models and mobility management methodologies. The discussion includes three aspects. Firstly, we discuss mobility management of mobile sensors for the purposes of forming a better WSN, enhancing network coverage and connectivity, and relocating some sensors. Secondly, we introduce path-planning methods for data ferries to relay data between isolated sensors and to extend a WSN's lifetime. Finally, we review some existing platforms and discuss several interesting applications of mobile WSNs. Copyright © 2010 John Wiley & Sons, Ltd.
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paper_title: Real time evaluation of shortest remaining processing time based schedulers for traffic congestion control using wireless sensor networks

paper_content:

Pre-timed traffic signals are inefficient in optimizing the traffic flow throughout the day, resulting in greater waiting times at the intersections particularly in congested urban areas during peak hours. Traffic actuated signals use real time traffic data obtained from sensors at the intersections to service queues intelligently. We developed a test bed for the real time evaluation of adaptive traffic light control algorithms using the microscopic traffic simulation open source software, SUMO (Simulation of Urban Mobility), and the AVR 32-bit microcontroller. An interface was developed between SUMO and the AVR microcontroller in which we used the simulation data generated by SUMO as an input to the microcontroller which executed the scheduling algorithms and sent commands back to SUMO for changing the states of the traffic signals accordingly. We implemented four scheduling algorithms in SUMO through the AVR microcontroller, the effect of the algorithms on the traffic network was studied using SUMO and execution times of the scheduling algorithms were measured using the AVR microcontroller. Through this interface, scheduling algorithms can be evaluated more effectively and accurately as compared to the case in which the algorithms are fed with data using pseudo random number generators.
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paper_title: Effective Urban Traffic Monitoring by Vehicular Sensor Networks

paper_content:

Traffic monitoring in urban transportation systems can be carried out based on vehicular sensor networks. Probe vehicles (PVs), such as taxis and buses, and floating cars (FCs), such as patrol cars for surveillance, can act as mobile sensors for sensing the urban traffic and send the reports to a traffic-monitoring center (TMC) for traffic estimation. In the TMC, sensing reports are aggregated to form a traffic matrix, which is used to extract traffic information. Since the sensing vehicles cannot cover all the roads all the time, the TMC needs to estimate the unsampled data in the traffic matrix. As this matrix can be approximated to be of low rank, matrix completion (MC) is an effective method to estimate the unsampled data. However, our previous analysis on the real traces of taxis in Shanghai reveals that MC methods do not work well due to the uneven samples of PVs, which is common in urban traffic. To exploit the intrinsic relationship between the unevenness of samples and traffic estimation error, we study the temporal and spatial entropies of samples and successfully define the important criterion, i.e., average entropy of the sampling process. A new sampling rule based on this relationship is proposed to improve the performance of estimation and monitoring. With the sampling rule, two new patrol algorithms are introduced to plan the paths of controllable FCs to proactively participate in traffic monitoring. By utilizing the patrol algorithms for real-data-set analysis, the estimation error reduces from 35% to about 10%, compared with the random patrol or interpolation method in traffic estimation. Both the validity of the exploited relationship and the effectiveness of the proposed patrol control algorithms are demonstrated.
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paper_title: Efficient Data Propagation in Traffic-Monitoring Vehicular Networks

paper_content:

Road congestion and traffic-related pollution have a large negative social and economic impact on several economies worldwide. We believe that investment in the monitoring, distribution, and processing of traffic information should enable better strategic planning and encourage better use of public transport, both of which would help cut pollution and congestion. This paper investigates the problem of efficiently collecting and disseminating traffic information in an urban setting. We formulate the traffic data acquisition problem and explore solutions in the mobile sensor network domain while considering realistic application requirements. By leveraging existing infrastructure such as traveling vehicles in the city, we propose traffic data dissemination schemes that operate on both the routing and the application layer; our schemes are frugal in the use of the wireless medium, rendering our system interoperable with the proliferation of competing applications. We introduce the following two routing algorithms for vehicular networks that aim at minimizing communication and, at the same time, adhering to a delay threshold set by the application: 1) delay-bounded greedy forwarding and 2) delay-bounded minimum-cost forwarding. We propose a framework that jointly optimizes the two key processes associated with monitoring traffic, i.e., data acquisition and data delivery, and provide a thorough experimental evaluation based on realistic vehicular traces on a real city map.
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paper_title: Instrumentation for safe vehicular flow in intelligent traffic control systems using wireless networks

paper_content:

This paper describes a ZigBee based wireless system to assists traffic flow on arterial urban roads. Real-time simulation in laboratory environment is conducted to determine the traffic throughput to avoid possible congestions or ease existing congestions. Random numbers are generated to mimic approaching traffic, and this information is shared by a ZigBeebased real-time wirelessly network. Wireless nodes are connected to different PLCs representing different traffic lights in a cluster. Once the information is shared the timing and sequencing decisions are taken collectively in a synchronized manner. In this paper, the information is displayed on SCADA connected to each PLC for viewing the characteristics of continuous vehicular flow. It is found that the topology of the network can play an important role in the throughput of data, which may be critical in safety critical operations such as the control of traffic lights. This paper aims to highlight some of the possible effects of dataflow flow and time-delays faced by modern intelligent control of traffic lights.
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paper_title: Research on Traffic Monitoring Network and Its Traffic Flow Forecast and Congestion Control Model Based on Wireless Sensor Networks

paper_content:

In this paper, we have made a comprehensive study about the key technologies including applying wireless sensor networks to the traffic monitoring network, its traffic flow forecast based on gray forecasting model and traffic congestion control. According to the features that wireless sensor networks have no space constraints, flexible distribution, mobile convenience and quick reaction, we present a scheme that uses wireless sensor networks to monitor city transport vehicles and have designed a traffic monitoring system based on wireless sensor network that is applicable to all types of city environment. With the system, we can monitor the important roads that are easily blocked and find out the time changing law of traffic congestion, and then put the focus on monitoring them in order to greatly reduce the investment and achieve high efficiency. As far as the traffic flow forecasting methods concerned, we use Adaptive GM (1, 1) Model which have a real-time rolling forecast for city traffic and have a better forecast results. Because of the fewer study about the traffic congestion control in the current academia, we make a deep study about the traffic congestion control issues in this article. Learn from mature congestion control algorithm in computer network, we have designed an algorithm of traffic flow congestion control and scheduling for traffic network, which is called TRED. We have used it for real-time traffic scheduling and have opened up a new way to study and solve traffic congestion control problems.
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paper_title: Wireless sensor networks for traffic monitoring in a logistic centre

paper_content:

Abstract A wireless sensor network (WSN) is a net of small sensor nodes, communicating using wireless technology to collect data. It combines distributed sensing and wireless communication, integrated in a self-powered small device with limited computation and memory functions. In this research, a WSN for traffic monitoring was installed and tested in the area of a logistic platform, the freight village of Turin. The sensor network layout was designed to detect all vehicles entering and leaving the area as well as the zones to which they are relating. One peculiarity of the logistic centre installation is related to the sensors’ locations on the roadway: as it was not possible to install sensors in optimal locations, characterised by almost-constant vehicle speed, scarce lane changing, and stationary vehicle pattern, the detection system accuracy requires assessment using vehicle count and classification. After a statistical analysis of system performance under different traffic conditions, a method to analyse and correct detection data is then proposed to reach satisfactory accuracy even in atypical installations.
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paper_title: Improving emergency messages transmission delay in road monitoring based WSNs

paper_content:

The main wireless technology used for events sensing and data collection is wireless sensor devices. These sensors are mounted on vehicles or in the roadside to send data collected periodically or upon incident detection. In this latter case, ensuring low transmission delay from the detector sensor to WSNs gateway is a real challenge. Indeed, faster notification of the Traffic Management System (TMS) leads to more efficient reaction to the emergency situation. Thus, cars collision and human lives loss as well as road traffic jam will be mitigated. In this paper, we investigate the Medium Access Control (MAC) layer in WSNs to improve the real time data collection scheme. To this end, we propose an enhanced backoff selection scheme for IEEE 802.15.4 protocol to ensure fast transmission of the detected events on the road towards the TMS. The main feature of our scheme is its ability to assign a shorter waiting time for messages carrying critical information without changing the basic principle of the backoff mechanism. The obtained simulation results under various scenarios have proven the effectiveness of our scheme in terms of transmission delay reduction.
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paper_title: Intelligent Vehicle Recognition based on Wireless Sensor Network

paper_content:

One of the main requirements of any intelligent transportation system is to be able to identify vehicles in the traffic. This paper presents an intelligent vehicle identification system used within a complete solution for a traffic monitoring system thatusesa novelwireless sensor network architecture to monitor traffic. A novel wireless sensor network architecture to monitor traffic is proposed where a visual sensor node captures images of the traffic and sends them to the traffic control center for processing. Also, this paper compares between three main localization and recognition algorithms. To locate the vehicle logo in the traffic image a symmetry detection algorithm is used to detect the inherent symmetry in vehicle frontal images. A fine location of the logo is identified using three different methods in the region marked by the symmetry line. After locating the logo three feature sets are extracted and presented to the classifier to correctly identify the type of the vehicle. The results of the localization and recognition algorithms show the efficiency of the presented system in identifying vehicle types with a recognition rate over 90%.
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paper_title: Intelligent Traffic Light System to Prioritized Emergency Purpose Vehicles based on Wireless Sensor Network

paper_content:

The use of Wireless Sensor Network (WSN) has proved to be a very beneficial in the design of adaptive and dynamic traffic light intersection system that will minimize the waiting time of vehicles and also manage the traffic load at the intersection adaptively. In this paper, we propose an adaptive traffic intersection system based on Wireless Sensor Network where the traffic light of one intersection can communicate with the traffic light of the next neighboring intersections and traffic clearance will be prioritized for special vehicles with the help of sensors. General Terms: Wireless Sensor Network.
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paper_title: Design and Research on Traffic Signal of Wireless Sensor Network Based on Labview

paper_content:

In order to solve the increasingly serious traffic problems in the city, how to achieve effective management and control of the traffic information has become an urgent problem that should be solved in transportation of our country. This paper proposes a design on traffic signal of wireless sensor network based on LabVIEW, including traffic signal controller, GPRS wireless modem and LabVIEW interface. It adopts GPRS wireless telecommunication as the method to transport the data of traffic signal control. This method could solve the problem of high costs and the difficult problems in using wired telecommunication cable system. Traffic signal device adopts Single Chip Microcomputer to control, introduces the information collection module by using the front-end of the HMC5883L Magnetoresistive Sensor. It describes the GPRS technology and relating properties. The traffic signal monitor interface designed by LabVIEW software, and achieves the control of traffic signal. Keywords—GPRS; Traffic Signal; HMC5883L Magnetoresistive Sensor
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paper_title: Intelligent transportation system based on SIP/ZigBee architecture

paper_content:

In a heterogeneous network environment, constructing applications of remote distributed intelligent transportation system (ITS) are faced with complex communication problems proposed by online management, data acquisition and the coordination control of traffic node devices. Therefore, a framework based on SIP/ZigBee architecture is proposed. By using SIP and its extensions, a seamless convergence of traffic measurement and control network between the Internet and a short-range wireless sensor and actuator networks (WSAN) can be achieved. The application result shows that various remote communications and control operations of ITS distributed nodes can be unified and simplified.
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paper_title: Instrumentation for safe vehicular flow in intelligent traffic control systems using wireless networks

paper_content:

This paper describes a ZigBee based wireless system to assists traffic flow on arterial urban roads. Real-time simulation in laboratory environment is conducted to determine the traffic throughput to avoid possible congestions or ease existing congestions. Random numbers are generated to mimic approaching traffic, and this information is shared by a ZigBeebased real-time wirelessly network. Wireless nodes are connected to different PLCs representing different traffic lights in a cluster. Once the information is shared the timing and sequencing decisions are taken collectively in a synchronized manner. In this paper, the information is displayed on SCADA connected to each PLC for viewing the characteristics of continuous vehicular flow. It is found that the topology of the network can play an important role in the throughput of data, which may be critical in safety critical operations such as the control of traffic lights. This paper aims to highlight some of the possible effects of dataflow flow and time-delays faced by modern intelligent control of traffic lights.
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paper_title: Implementing Intelligent Traffic Control System for Congestion Control Ambulance Clearance and Stolen Vehicle Detection

paper_content:

Traffic congestion is a major problem in cities of developing Countries like India. Growth in urban population and the middle-class segment consume vehicles to the rising number of vehicles in the cities. Congestion on roads eventually results in slow moving traffic, which increases the time of travel, thus be notable as one of the major issues in metropolitan cities. Emergency vehicles like ambulance and fire trucks need to reach their destinations at the earliest. If they spend a lot of time in traffic jams, valued lives of many people may be in danger. Here the image sequences from a camera are analyzed using various edge detection and object counting methods to obtain the most efficient technique. Then, the number of vehicles at the intersection is evaluated and traffic is efficiently managed. The traffic signal indication continuously glows to green as long as the emergency vehicle is waiting at the traffic lane. After the vehicle crossed the junction, automatically the traffic signals follow the previous pattern generation of traffic signals. This can be implemented in LABVIEW.
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paper_title: An Approach towards Traffic Management System using Density Calculation and Emergency Vehicle Alert

paper_content:

Now a day's many of the things get controlled automatically. Everything is getting controlled using the mechanical or the automated systems. In every field machines are doing the human works. But still some area is controlled manually. For example traffic controls, road control, parking controlling. Keeping these things in mind we are trying to develop the project to automate the traffic tracking for the square. To make any project more useful and acceptable by any organization we need to provide multiple features in a single project. Keeping these things in consideration proposed system is less with multiple methodologies which can be used in traffic control system It is important to know the road traffic density real time especially in mega cities for signal control and effective traffic management. In recent years, video monitoring and surveillance systems have been widely used in traffic management.Hence, traffic density estimation and vehicle classification can be achieved using video monitoring systems. In most vehicle detection methods in the literature, only the detection of vehicles in frames of the given video is emphesized. However, further analysis is needed in order to obtain the useful information for traffic management such as real time traffic density and number of vehicle types passing these roads. This paper presents emergency vehicle alert and traffic density calculation methods using IR and GPS
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paper_title: Intelligent transportation systems for wireless sensor networks based on ZigBee

paper_content:

Combining with the characteristics of intelligent transportation system and introduces wireless sensor networks technology. This paper illustrates a kind of intelligent transportation system solution of wireless sensor networks based on ZigBee technology. Through the comprehensive analysis of three respects of network topology, energy saving as well as being stable and reliable, this paper brings forward the hardware design of sensor network node and network protocols suitable for urban public transport system. Online travel buses can be monitored in real-time, to achieve the purpose of intelligent management. This system has higher cost performance compare with the current GPS used in public transit system.
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paper_title: Research on Traffic Monitoring Network and Its Traffic Flow Forecast and Congestion Control Model Based on Wireless Sensor Networks

paper_content:

In this paper, we have made a comprehensive study about the key technologies including applying wireless sensor networks to the traffic monitoring network, its traffic flow forecast based on gray forecasting model and traffic congestion control. According to the features that wireless sensor networks have no space constraints, flexible distribution, mobile convenience and quick reaction, we present a scheme that uses wireless sensor networks to monitor city transport vehicles and have designed a traffic monitoring system based on wireless sensor network that is applicable to all types of city environment. With the system, we can monitor the important roads that are easily blocked and find out the time changing law of traffic congestion, and then put the focus on monitoring them in order to greatly reduce the investment and achieve high efficiency. As far as the traffic flow forecasting methods concerned, we use Adaptive GM (1, 1) Model which have a real-time rolling forecast for city traffic and have a better forecast results. Because of the fewer study about the traffic congestion control in the current academia, we make a deep study about the traffic congestion control issues in this article. Learn from mature congestion control algorithm in computer network, we have designed an algorithm of traffic flow congestion control and scheduling for traffic network, which is called TRED. We have used it for real-time traffic scheduling and have opened up a new way to study and solve traffic congestion control problems.
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paper_title: Adaptive Traffic Signal Flow Control Using Wireless Sensor Networks

paper_content:

The growth and scale of vehicles today makes management of traffic a constant problem. Measures such as toll based systems with electronic smart card recognition, advance notification on traffic status and fixed time control signaling are some of the measures considered to alleviate the traffic woes of passengers. However a sizeable sum of problems still exists due to incomplete utilization of the road systems. In this paper, an approach to make the traffic signal adaptive to the dynamic traffic flow using wireless sensor network is proposed. The proposed approach is simulated in LabView software and compared with the existing fixed time control scheme. From the results obtained it is observed that the proposed approach outperforms the existing approaches.
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paper_title: Intelligent traffic management with wireless sensor networks

paper_content:

Vehicular travel is gaining importance everywhere, particularly in large urban areas. The current technologies that support vehicular travel like wired sensors, inductive loops, surveillance camera etc., are expensive and also require high maintenance cost. Further the accuracy of these devices also depends on environment conditions. The typical traditional approaches attempt to optimize traffic lights control for a particular density and configuration of traffic. However, the major disadvantage of using these techniques is that the dynamic behavior of traffic densities and configurations change is difficult to model constantly. Traffic seems to be an adaptation problem rather than an optimization problem. This paper therefore tries to address the above issue, and hence we propose algorithms which perform adaptive traffic light control using a wireless sensor network setup. The paper aims at analyzing methods to build an intelligent system that can blend and support some of the existing technologies of traffic control and therefore reduce the average waiting time of vehicles on a junction. The proposed algorithms are adaptive to traffic flow at any intersection point of roads. Simulations of the real-life traffic scenarios are conducted in a simulated platform called Green Light District Simulator (GLD) to generate graph average waiting time versus cycles. The results generated show that the proposed method is effective for the traffic control in a real road intersection.
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paper_title: A novel approach for dynamic traffic lights management based on Wireless Sensor Networks and multiple fuzzy logic controllers

paper_content:

HighlightsFlexible, scalable traffic lights dynamic control system for isolated intersections.Multiple parallel fuzzy controllers dynamically manage both the phase and green time.Outperforms other works in terms of vehicle waiting time and balancing between phases.Very effective under heavy traffic and when phases have unbalanced arrival rates.Lightweight effective implementable on COTS devices: broad practical impact expected. This paper proposes a novel approach to dynamically manage the traffic lights cycles and phases in an isolated intersection. The target of the work is a system that, comparing with previous solutions, offers improved performance, is flexible and can be implemented on off-the-shelf components. The challenge here is to find an effective design that achieves the target while avoiding complex and computationally expensive solutions, which would not be appropriate for the problem at hand and would impair the practical applicability of the approach in real scenarios. The proposed solution is a traffic lights dynamic control system that combines an IEEE 802.15.4 Wireless Sensor Network (WSN) for real-time traffic monitoring with multiple fuzzy logic controllers, one for each phase, that work in parallel. Each fuzzy controller addresses vehicles turning movements and dynamically manages both the phase and the green time of traffic lights. The proposed system combines the advantages of the WSN, such as easy deployment and maintenance, flexibility, low cost, noninvasiveness, and scalability, with the benefits of using four parallel fuzzy controllers, i.e., better performance, fault-tolerance, and support for phase-specific management. Simulation results show that the proposed system outperforms other solutions in the literature, significantly reducing the vehicles waiting times. A proof-of-concept implementation on an off-the-shelf device proves that the proposed controller does not require powerful hardware and can be easily implemented on a low-cost device, thus paving the way for extensive usage in practice.
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paper_title: Efficient dynamic traffic control system using wireless sensor networks

paper_content:

This paper proposes an improved traffic control system by having dynamic time limits at the traffic signal intersections. The proposed system uses sensors to find the traffic conditions to dynamically control the traffic. Prevailing static traffic control system may block emergency vehicles such as ambulance due to traffic congestion. The proposed Efficient Dynamic Traffic Control System (EDTCS) has Traffic Control Unit (TCU), Monitor Unit (MU) and Road Side Unit (RSU). RSU contains RFID reader which reads the unique RFID code for an emergency vehicle and send it to MU. MU uses sensors such as proximity switch and RFID tags to get the count of normal and emergency vehicles respectively and sensed information is sent to TCU. TCU receives the count of normal and emergency vehicles and changes the signal dynamically by comparing the count obtained from different lanes. The proposed EDTCS saves travel time and gives a special priority to emergency vehicles like ambulance.
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paper_title: A distributed algorithm for multiple intersections adaptive traffic lights control using a wireless sensor networks

paper_content:

In this article, we detail and evaluate a distributed algorithm that defines the green lights sequence and duration in a multi-intersection intelligent transportation system (ITS). We expose the architecture of a wireless network of sensors deployed at intersections, which takes local decisions without the help of a central entity. We define an adaptive algorithm, called TAPIOCA (distribuTed and AdaPtive IntersectiOns Control Algorithm), that uses data collected by this sensor network to decide dynamically of the green light sequences, considering three objectives: (i) reducing the users average waiting time while limiting the starvation probability; (ii) selecting in priority the movements that have the best load discharge potential and (iii) synchronizing successive lights, for example to create green waves. Simulation results performed with the SUMO simulator show that TAPIOCA achieves a low average waiting time of vehicles and reacts quickly to traffic load increases, compared to other dynamic strategies and to pre-determined schedules.
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paper_title: Simulation of dynamic traffic control system based on wireless sensor network

paper_content:

The use of wireless sensor network in the smart traffic control systems is very beneficial and starting to be very promising in the design and implementation for such systems. It will help in saving people time and adapt the intersections traffic lights to the traffic loads from each direction. In this paper we present an intelligent traffic signals control system based on a wireless sensor network (WSN). It uses the vehicle queue length during red cycle to perform better control in the next green cycle. The main objective is to minimize the average waiting time that will reduce the queues length and do better traffic management based on the arrivals in each direction. The system also includes an approach to alert the people about the red light crossing to minimize the possibility of accidents due to red light crossing violations. The system was simulated and results are shown in the end of this paper.
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paper_title: Adaptive Traffic Light Control in Wireless Sensor Network-Based Intelligent Transportation System

paper_content:

We investigate the problem of adaptive traffic light control using real-time traffic information collected by a wireless sensor network (WSN). Existing studies mainly focused on determining the green light length in a fixed sequence of traffic lights. In this paper, we propose an adaptive traffic light control algorithm that adjusts both the sequence and length of traffic lights in accordance with the real time traffic detected. Our algorithm considers a number of traffic factors such as traffic volume, waiting time, vehicle density, etc., to determine green light sequence and the optimal green light length. Simulation results demonstrate that our algorithm produces much higher throughput and lower vehicle's average waiting time, compared with a fixed-time control algorithm and an actuated control algorithm. We also implement proposed algorithm on our transportation testbed, iSensNet, and the result shows that our algorithm is effective and practical.
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paper_title: Intelligent Traffic Light Flow Control System Using Wireless Sensors Networks

paper_content:

Vehicular traffic is continuously increasing around the world, especially in large urban areas. The resulting congestion has become a major concern to transportation specialists and decision makers. The existing methods for traffic management, surveillance and control are not adequately efficient in terms of performance, cost, maintenance, and support. In this paper, the design of a system that utilizes and efficiently manages traffic light controllers is presented. In particular, we present an adaptive traffic control systembased on a new traffic infrastructure using Wireless Sensor Network (WSN) and using new techniques for controlling the traffic flow sequences. These techniques are dynamically adaptive to traffic conditions on both single and multiple intersections. A WSN is used as a tool to instrument and control traffic signals roadways, while an intelligent traffic controller is developed to control the operation of the traffic infrastructure supported by the WSN. The controller embodies traffic system communication algorithm (TSCA) and the traffic signals time manipulation algorithm (TSTMA). Both algorithms are able to provide the system with adaptive and efficient traffic estimation represented by the dynamic change in the traffic signals' flow sequence and traffic variation. Simulation results show the efficiency of the proposed scheme in solving traffic congestion in terms of the average waiting time and average queue length on the isolated (single) intersection and efficient global traffic flow control on multiple intersections. A test bed was also developed and deployed for real measurements. The paper concludes with some future highlights and useful remarks.
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paper_title: Adaptive Traffic Light Control of Multiple Intersections in WSN-Based ITS

paper_content:

We investigate the problem of adaptive traffic light control of multiple intersections using real-time traffic data collected by a wireless sensor network (WSN). Previous studies mainly focused on optimizing the intervals of green lights in fixed sequences of traffic lights and ignored the traffic flow's characteristics and special traffic circumstances. In this paper, we propose an adaptive traffic light control scheme that adjusts the sequences of green lights in multiple intersections based on the real- time traffic data, including traffic volume, waiting time, number of stops, and vehicle density. Subsequently, the optimal green light length can be calculated from the local traffic data and traffic condition of neighbor intersections. Simulation results demonstrate that our scheme produces much higher throughput, lower average waiting time and fewer number of stops, compared with three control approaches: the optimal fixed-time control, an actuated control and an adaptive control.
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paper_title: Traffic lights detection and state estimation using Hidden Markov Models

paper_content:

The detection of a traffic light on the road is important for the safety of persons who occupy a vehicle, in a normal vehicles or an autonomous land vehicle. In normal vehicle, a system that helps a driver to perceive the details of traffic signals, necessary to drive, could be critical in a delicate driving manoeuvre (i.e crossing an intersection of roads). Furthermore, traffic lights detection by an autonomous vehicle is a special case of perception, because it is important for the control that the autonomous vehicle must take. Multiples authors have used image processing as a base for achieving traffic light detection. However, the image processing presents a problem regarding conditions for capturing scenes, and therefore, the traffic light detection is affected. For this reason, this paper proposes a method that links the image processing with an estimation state routine formed by Hidden Markov Models (HMM). This method helps to determine the current state of the traffic light detected, based on the obtained states by image processing, aiming to obtain the best performance in the determination of the traffic light states. With the proposed method in this paper, we obtained 90.55% of accuracy in the detection of the traffic light state, versus a 78.54% obtained using solely image processing. The recognition of traffic lights using image processing still has a large dependence on the capture conditions of each frame from the video camera. In this context, the addition of a pre-processing stage before image processing could contribute to improve this aspect, and could provide a better results in determining the traffic light state.
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paper_title: An Intelligent Fuzzy Control for Crossroads Traffic Light

paper_content:

The fuzzy control algorithm that carries on the intelligent control twelve phases three traffic lanes single crossroads traffic light, works well in the real-time traffic flow under flexible operation. The procedures can be described as below: first, the number of vehicles of all the lanes can be received through the sensor, and the phase with the largest number is stipulated to be highest priority, while the phase turns to the next one from the previous, it transfers into the highest priority. Then the best of the green light delay time can be figured out under the fuzzy rules reasoning on the current waiting formation length and general formation length. The simulation result indicates the fuzzy control method on vehicle delay time compared with the traditional timed control method is greatly improved.
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paper_title: Towards tag antenna based sensing - An RFID displacement sensor

paper_content:

Displacements can be used as indicators of structural health and are measured by commercially available sensors that need to be accurate and cost effective. In this paper, we examine a technique to utilize a UHF RFID tag antenna as a displacement sensor by mapping structural deformation to a change in RFID tag characteristics. We evaluate how changes in two different parameters, a) tag backscatter power and b) minimum reader transmit power required for RFID chip activation, can be mapped to structural deformation. The theoretical principles of sensor development are first discussed followed by a presentation of the results of experimentation. It is demonstrated that the sensor is sensitive to displacements for a dynamic range of 40 mm.
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paper_title: A dynamic traffic light management system based on wireless sensor networks for the reduction of the red-light running phenomenon

paper_content:

The real-time knowledge of information concerning traffic light junctions represents a valid solution to congestion problems with the main aim to reduce, as much as possible, accidents. The Red Light Running (RLR) is a behavioural phenomenon that occurs when the driver must to choose to cross (or not) the road when the traffic light changes from green to yellow. Most of the time the drivers cross even during transitions from yellow to red and, as a consequence, the possibility of accidents increases. This often occurs because the drivers wait too much in the traffic light queue as a consequence of the fact that the traffic light is not well balanced. In this paper we propose a technique that, based on information gathered through a wireless sensor network, dynamically processes green times in a traffic light of an isolated intersection. The main aim is to optimise the waiting time in the queue and, as a consequence, reduce the RLR phenomenon occurrence.
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paper_title: Feasibility of deploying wireless sensor based road side solutions for Intelligent Transportation Systems

paper_content:

The effectiveness of Intelligent Transportation Systems depends on the accuracy and timely reliable provisioning of real time data supplied by traffic data collection mechanisms. Data collection through wireless sensor networks is a very effective approach due to their easy installation, low cost, processing capabilities, small size, flexibility, and wireless communication capabilities. WSN are used in ITS for smart parking lots, adaptive traffic light control, accident avoidance and traffic estimation etc. In this paper we propose a WSN based road side communication architecture and system that can be utilized for the intelligent control and management of vehicular traffic at road intersections. In the proposed architecture, the end nodes are carried by vehicles that communicate with road side units, which in turn send the data to the coordinator module at the intersection. We introduce a reliable and robust channel switching technique that reduces the response time, energy consumption and connectivity delay while increasing the reliability of packet delivery. We perform sensitivity analysis of the proposed system architecture by varying various communication parameters to determine optimum system configuration. The results prove the integrity and feasibility of the deployment of our proposed architecture.
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paper_title: A novel approach for dynamic traffic lights management based on Wireless Sensor Networks and multiple fuzzy logic controllers

paper_content:

HighlightsFlexible, scalable traffic lights dynamic control system for isolated intersections.Multiple parallel fuzzy controllers dynamically manage both the phase and green time.Outperforms other works in terms of vehicle waiting time and balancing between phases.Very effective under heavy traffic and when phases have unbalanced arrival rates.Lightweight effective implementable on COTS devices: broad practical impact expected. This paper proposes a novel approach to dynamically manage the traffic lights cycles and phases in an isolated intersection. The target of the work is a system that, comparing with previous solutions, offers improved performance, is flexible and can be implemented on off-the-shelf components. The challenge here is to find an effective design that achieves the target while avoiding complex and computationally expensive solutions, which would not be appropriate for the problem at hand and would impair the practical applicability of the approach in real scenarios. The proposed solution is a traffic lights dynamic control system that combines an IEEE 802.15.4 Wireless Sensor Network (WSN) for real-time traffic monitoring with multiple fuzzy logic controllers, one for each phase, that work in parallel. Each fuzzy controller addresses vehicles turning movements and dynamically manages both the phase and the green time of traffic lights. The proposed system combines the advantages of the WSN, such as easy deployment and maintenance, flexibility, low cost, noninvasiveness, and scalability, with the benefits of using four parallel fuzzy controllers, i.e., better performance, fault-tolerance, and support for phase-specific management. Simulation results show that the proposed system outperforms other solutions in the literature, significantly reducing the vehicles waiting times. A proof-of-concept implementation on an off-the-shelf device proves that the proposed controller does not require powerful hardware and can be easily implemented on a low-cost device, thus paving the way for extensive usage in practice.
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paper_title: Using DTMon to monitor transient flow traffic

paper_content:

We evaluate the performance of the DTMon dynamic traffic monitoring system to measure travel times and speeds in transient flow traffic caused by non-recurring congestion. DTMon uses vehicular networks and roadside infrastructure to collect data from passing vehicles. We show DTMon's ability to gather high-quality real-time traffic data such as travel time and speed. These metrics can be used to detect transitions in traffic flow (e.g., caused by congestion) especially where accurate flow rate information is not available. We evaluate the accuracy and latency of DTMon in providing traffic measurements using two different methods of message delivery. We show the advantages of using dynamically-defined measurement points for monitoring transient flow traffic. We compare DTMon with currently in-use probe-based systems (e.g., AVL) and fixed-point sensors and detectors (e.g., ILD).
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Title: A Survey on Urban Traffic Management System Using Wireless Sensor Networks

Section 1: Introduction
Description 1: This section introduces the problem of increased vehicle usage, traffic congestion, and the need for intelligent traffic management systems using wireless sensor networks.

Section 2: Key Issues in Urban Traffic Management System
Description 2: This section discusses the key issues related to urban traffic management, such as recurring and non-recurring traffic congestion, and the detection of non-recurring congestion.

Section 3: Overview
Description 3: This section provides an overview of the sensing evolution, traffic sensing technologies, the characteristics of a general sensor node, and the hierarchical functionality of a WSN-based urban traffic management system.

Section 4: Sensing Evolution
Description 4: This section details the development and advancements in sensor technology and their applications in traffic management.

Section 5: Traffic Sensing Technologies
Description 5: This section describes various traffic sensing technologies including their advantages and disadvantages in terms of installation, maintenance, and performance.

Section 6: General Sensor Node
Description 6: This section elaborates on the components and functionalities of a general sensor node in traffic monitoring.

Section 7: Hierarchy of Urban Traffic Management Systems
Description 7: This section explains the structure and functions of the three subsystems in an urban traffic management system.

Section 8: State-of-the-Art Review
Description 8: This section reviews related projects, architectures, data collection schemes, routing algorithms, congestion avoidance schemes, priority-based traffic management schemes, and average waiting time reduction schemes.

Section 9: Related Projects
Description 9: This section introduces various projects on urban traffic management that focus on different traffic parameters.

Section 10: Specific Architectures, Data Collection Schemes, and Routing Algorithms
Description 10: This section discusses explicit architectures, data collection schemes, and routing algorithms proposed for WSN-based urban traffic management.

Section 11: Congestion Avoidance Schemes
Description 11: This section outlines several WSN-based schemes and techniques developed to reduce traffic congestion.

Section 12: Priority-Based Traffic Management Schemes
Description 12: This section details WSN-based traffic management schemes designed to prioritize emergency vehicles.

Section 13: Average Waiting Time Reduction Schemes
Description 13: This section presents various WSN-based methodologies for reducing the average waiting time of vehicles at intersections.

Section 14: Challenges
Description 14: This section discusses significant challenges and issues faced by WSN-based traffic management systems, such as connectivity, coverage, energy cost, congestion, and real-time incident notifications.

Section 15: Conclusions and Future Work
Description 15: This section provides a summary of the survey, discusses the main challenges, and outlines potential directions for future research in urban traffic management systems using WSNs.