Vehicular Traffic Environment Research Articles

Optical Camera Communication for Vehicular Applications: A Survey

The tremendously increasing interest in visible light communication (VLC) and the attempt to use readily available light emitting diodes (LEDs) and off-the-shelf cameras have sparked great potential for new technology called optical camera communication (OCC). Recently, enhanced vehicular communication with OCC is in demand to ensure driving safety in increasingly dense vehicular traffic environments. In this paper, we survey the recent advancements made in the applications of OCC in vehicular communication. The existing OCC methodologies and several challenges arising from optical wireless channels for vehicular communication technologies in an intelligent transport system (ITS) are presented, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-everything (V2X) communication. Furthermore, we provide insights into the future potential of the OCC-based ITS, including privacy and security issues and integration of artificial intelligence (AI) with OCC for enhancing communication performance.

Numerical Investigation of Aerodynamic Noise Reduction of Nonpneumatic Tire Using Nonsmooth Riblet Surface.

Unlike conventional pneumatic tires, the nonpneumatic tires (NPT) are explosion proof and simple to maintain and provide low rolling resistance. At high vehicle speeds, however, the complex airflow produced by the open flexible-spoke structure of NPT yields high aerodynamic noise, which contributes to sound pollution in the vehicular traffic environment. Inspired by the idea that a nonsmooth riblet structure can affect fluid flow and offer noise reduction, the analyses of the effect of the nonsmooth riblet surface on the aerodynamic noise of an NPT and noise reduction mechanism were presented in this paper. First, computational fluid dynamics (CFD) was used to analyze the surface pressure coefficient characteristics of a smooth flexible-spoke tire rolling at a speed of 80 km/h and subsequently validating the numerical simulation results by comparing them with published test results. Secondly, large eddy simulation (LES) and the Ffowcs Williams–Hawkings (FW-H) method were, respectively, used to determine the transient flow and far-field aerodynamic noise. Then, the mechanism of noise reduction was investigated using a vortex theory. Based on the vortex theory, the positions and strengths of noise sources were determined using the Lamb vector. Finally, according to the fluid boundary layer theory, a nonsmooth riblet surface was arranged on the surface of the spokes, and the influences of the riblet structure parameters, including size, position, and direction, on aerodynamic noise were analyzed. Based on the vortex theory, it was found that the nonsmooth riblet structure can reduce the Lamb vector, suppress the generation of flow vortices, decrease acoustic source strength, and effectively decrease noise up to 5.18 dB using the optimized riblet structure. The study results provide a theoretical basis for the structural design of a new low-noise NPT.

Cybersecurity Measures for Geocasting in Vehicular Cyber Physical System Environments

Geocasting in vehicular communication has witnessed significant attention due to the benefits of location oriented information dissemination in vehicular traffic environments. Various measures have been applied to enhance geocasting performance including dynamic relay area selection, junction nodes incorporation, caching integration, and geospatial distribution of nodes. However, the literature lacks toward geocasting under malicious relay vehicles leading to cybersecurity concern in vehicular traffic environments. In this context, this paper presents cybersecurity measures for geocasting in vehicular traffic environments focusing on security oriented vehicular connectivity. Specifically, a vehicular intrusion prevention technique is developed to measure the connectivity between the cache agent (CA) and cache user (CU) vehicles. The connectivity between static transport vehicles and CA/CU is measured via vehicular intrusion detection approach. The performance of the proposed vehicular cybersecurity measure is evaluated in realistic traffic environments. The comparative performance evaluation attests the benefits of security oriented geocasting in vehicular traffic environments.

A smart integrated environment for vehicular traffic simulation

SummaryGlobally, urbanization has increased due to the availability of the facilities, jobs, and better standard of living in cities. Increase in urban population has caused increase in urban commute. The increased pressure on urban settlements has made design and optimization of urban civil infrastructure very challenging especially road transport infrastructure. Domain experts such as transportation managers, engineers, scientist, and academics need effective, easy, and readily usable computational modeling and simulation tools to conduct systematic inquiry for design and optimization of the transportation system. Free and open‐source software (FOSS) community has developed many vehicular traffic simulation software that are cost‐effective and extensible, however are difficult to use. Usually, domain experts do not have hands‐on software skills such as XML‐based interfaces, software source versioning, and build management. To bridge this gap, in our work, an integrated development environment (IDE), namely, integrated vehicular traffic simulation environment (ITE), has been developed. ITE is developed on top of an existing FOSS multimodal open‐source vehicular‐traffic simulator (MovSim). ITE includes a scenario building tool for domain experts. It could be used to model road infrastructure and vehicular traffic in an integrated manner. The tool could be used to build and experiment novel traffic infrastructures and policies. Our work helps in reducing learning curve of domain experts by providing a free and open source, easy and readily usable vehicular traffic simulation tool.

Evaluation of Ad-Hoc Routing Protocols in a Vehicular Traffic Environment using SUMO and NS2

Evaluation of Ad-Hoc Routing Protocols in a Vehicular Traffic Environment using SUMO and NS2

Delimitated Anti Jammer Scheme for Internet of Vehicle: Machine Learning Based Security Approach

Recently, Internet of vehicles (IoV) has witnessed significant research and development attention in both academia and industries due to the potential towards addressing traffic incidences and supporting green mobility. With the growing vehicular network density, jamming signal centric security issues have become challenging task for IoV network designers and traffic applications developers. Global positioning system (GPS) and roadside unit (RSU) centric related literature on location-based security approaches lacks signal characteristics consideration for identifying vehicular network intruders or jammers. In this context, this paper proposes a machine learning oriented as Delimitated Anti Jamming protocol for vehicular traffic environments. It focuses on jamming vehicle's discriminated signal detection and filtration for revealing precise location of jamming effected vehicles. In particular, a vehicular jamming system model is presented focusing on localization of vehicles in delimitated jamming environments. A foster rationalizer is employed to examine the frequency changes caused in signal strength due to the jamming or external attacks. A machine learning open-sourced algorithm namely, CatBoost has been utilized focusing on decision tree relied algorithm to predict the locations of jamming vehicle. The performance of the proposed anti jammer scheme is comparatively evaluated with the state of the art techniques. The evaluation attests the resistive characteristics of the anti-jammer technique considering precision, recall, F1 score and delivery accuracy metrics.

Learning to Boost Bottom-Up Fixation Prediction in Driving Environments via Random Forest

Saliency detection, an important step in many computer vision applications, can, for example, predict where drivers look in a vehicular traffic environment. While many bottom-up and top-down saliency detection models have been proposed for fixation prediction in outdoor scenes, no specific attempt has been made for traffic images. Here, we propose a learning saliency detection model based on a random forest (RF) to predict drivers' fixation positions in a driving environment. First, we extract low-level (color, intensity, orientation, etc.) and high-level (e.g., the vanishing point and center bias) features and then predict the fixation points via RF-based learning. Finally, we evaluate the performance of our saliency prediction model qualitatively and quantitatively. We use quantitative evaluation metrics that include the revised receiver operating characteristic (ROC), the area under the ROC curve value, and the normalized scan-path saliency score. The experimental results on real traffic images indicate that our model can more accurately predict a driver's fixation area, while driving than the state-of-the-art bottom-up saliency models.

Interference-Aware Multipath Video Streaming in Vehicular Environments

The multipath transmission is one of the suitable transmission methods for high data rate oriented communication such as video streaming. Each video packets are split into smaller frames for parallel transmission via different paths. One path may interfere with another path due to these parallel transmissions. The multipath oriented interference is due to the route coupling which is one of the major challenges in vehicular traffic environments. The route coupling increases channel contention resulting in video packet collision. In this context, this paper proposes an Interference-aware Multipath Video Streaming (I-MVS) framework focusing on link and node disjoint optimal paths. Specifically, a multipath vehicular network model is derived. The model is utilized to develop interference-aware video streaming method considering angular driving statistics of vehicles. The quality of video streaming links is measured based on packet error rate considering non-circular transmission range oriented shadowing effects. Algorithms are developed as a complete operational I-MVS framework. The comparative performance evaluation attests the benefit of the proposed framework considering various video streaming related metrics.

Inter Vehicle Distance Based Connectivity Aware Routing in Vehicular Adhoc Networks

Connectivity in vehicular traffic environment has witnessed significant attention due to the direct impact on the performance of most of the traffic safety applications of intelligent transport system. Various parameters such as density, speed, direction, link quality and inter vehicle distance (IVD) have been utilized for measuring connectivity. IVD has greater impact on connectivity and controls the impact of other parameters. Usage of real time IVD for measuring connectivity has not received sufficient attention in VANETs. This paper proposes IVD based connectivity aware routing (Ivd-CAR) for enhancing connectivity aware data dissemination. IVD calculation is robust and can effectively handle instantaneous GPS failure. Two localization techniques; namely, cooperative localization and Geometry based Localization are developed. Standard deviation of real time IVDs of a forwarding path is derived. Distribution of IVDs of a forwarding path is employed for estimating connectivity. Segment vehicle based next hop vehicle selection is utilized for incorporating network load, link quality and direction into consideration while selecting forwarding path. Simulations are carried out in ns2 to evaluate the performance of Ivd-CAR in realistic traffic environment. Comparative analysis of simulation results attests the superiority of Ivd-CAR to the state-of-the-art techniques: CSR and A-CAR.

Towards video streaming in IoT Environments: Vehicular communication perspective

Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues.

Real traffic-data based evaluation of vehicular traffic environment and state-of-the-art with future issues in location-centric data dissemination for VANETs

Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks (VANETs). Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carried out with three main objectives: (i) to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, (ii) to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and (iii) to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carried out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.

Multi-metric geographic routing for vehicular ad hoc networks

Maintaining durable connectivity during data forwarding in Vehicular Ad hoc Networks has witnessed significant attention in the past few decades with the aim of supporting most modern applications of intelligent transportation systems. Various techniques for next hop vehicle selection have been suggested in the literature. Most of these techniques are based on selection of next hop vehicles from fixed forwarding region with two or three metrics including speed, distance and direction, and avoid many other parameters of urban environments. In this context, this paper proposes a Multi-metric Geographic Routing (M-GEDIR) technique for next hop selection. It selects next hop vehicles from dynamic forwarding regions, and considers major parameters of urban environments including, received signal strength, future position of vehicles, and critical area vehicles at the border of transmission range, apart from speed, distance and direction. The performance of M-GEDIR is evaluated carrying out simulations on realistic vehicular traffic environments. In the comparative performance evaluation, analysis of results highlight the benefit of the proposed geographic routing as compared to the state-of-the-art routing protocols.

Impact of Sectorization/Vehicular Traffic on Minimum Cell Size for Information Capacity Increase in Cellular Systems

In this paper results of mathematical analysis sup-ported by simulation are used to study the impact of sectorization/vehicular traffic on the theoretical limit for cell size radius reduction in cellular wireless communication systems. Information capacity approach is used for the analysis. Attention is given to the active co-channel interfering cells. Because at carrier frequencies greater than 2 GHz, co-channel interfering cells beyond the first tier becomes dominant as the cell size radius reduces. Results show that for sectorized cellular wireless communication system operating at carrier frequency greater than 2 GHz and having smaller cell size radius in a traffic environment the second tier co-channel interference still becomes active. This causes a decrease in the information capacity of the cellular wireless system. For example for a heavy vehicular traffic environment, at a carrier frequency fC = 15.75 GHz, basic path loss exponent α = 2 and cell radius R = 100, 300 and 500 m for a six sector cellular the decrease in information capacity, because of interference from the second tier was 5.47, 3.36 and 2.78%.

E-DIR: a directional routing protocol for VANETs in a city traffic environment

In this paper, we examine the significance of position-based routing using edge nodes for forwarding the data in a vehicular ad hoc network. This approach minimises the path length by minimising the number of hops between source and destination vehicles. The proposed protocol is called edge node-based directional routing (E-DIR) since it uses edge nodes with DIR. A mathematical analysis has been presented to determine the number of successful hops between source and destination. We have simulated the protocol using MATLAB. The simulation results clearly show that the average number of successful hops for E-DIR is significantly higher than DIR. Further, the simulations also reveal that E-DIR performs better than DIR for high density vehicular traffic environment.

Phenotypic characterization of air-borne pink pigmented facultative methylotrophic bacteria from high vehicular traffic density environment in Manila, Philippines

Phenotypic characterization of air-borne pink pigmented facultative methylotrophic bacteria from high vehicular traffic density environment in Manila, Philippines