High Vehicle Density Research Articles

PENGARUH KEMACETAN DI SIMPANG CILIWUNG TERHADAP DERAJAD PELAYANAN DI SIMPANG PROGRESIF

Abstract Highway in Malang there that needs to be analyzed is Intersections Letjend S. Parman Street – Ciliwung Street and Letjend Sutoyo Street – Letjend Selorejo. The road is an arterial road in the city of Malang with a high vehicle density level (Saputra, 2013). The Street was a high traffic flow led to queues or long saturated flow that is not supported by the settings of the light signals in accordance with the conditions in the field so often causes congestion. From finding a solution the traffic density in the study Letjend S Parman Street – Ciliwung Street and Letjend Sutoyo Street – Letjend Selorejo with Indonesia Highway Capasity Manual (IHCM). After stages 3-signal coordination calculation in Ciliwung Intersection of Malang, Intersection obtained time peak hours at the intersection area occurred at 11.00 – 12.00 GMT. Performance 3-waay junction on the Ciliwung Malang at this time has not met the target. Seen from there is still a Degree of Saturation (DS) which do not meet the targets ( ≤ 0,75), namely 0,83. After having don e engineering into 3 phases and cycle time 100 minutes Degree of Saturation (DS) be 0,77. Keywords: intersection, peak hours, capacity and degree saturation

Profile of Fatal Road Traffic Accidents at Puducherry-An Autopsy based Study

Road traffic accident (RTA) is the leading cause of mortality and disability all over the world. The scenario is much worse in India where there is high density of vehicles on the roads. This study highlights the profile of fatal road traffic accidents occurred in the Union Territory of Puducherry in the calendar years 2012 and 2013. Male fatalities outnumbered thefemale fatalities and age group between 21 and 30 years (28%) was most commonly affected. Majority of the fatal accidents occurred in national highways (36.5%) and occupants of two wheeler vehicles were more vulnerable (40.3%). Highest number of fatalities were reported during first 2 hours of accident (47.3%), and it was observed that head injuries were the dominant cause of death (41.9%).

An Empirical study on MAC layer in IEEE 802.11p/WAVE based Vehicular Ad hoc Networks

Intelligent Transportation Systems use Vehicular Ad-hoc Networks to improve road safety. Dedicated Short Range Communications (DSRC or IEEE 802.11p) and Wireless Access in Vehicular Environments (WAVE or IEEE 1609 protocol suite) are the two important standards that govern communication in VANETs. However, DSRC based VANETs cannot guarantee to achieve the Quality of Service (QoS) requirements like reliability and latency under high vehicle density scenario due to network congestion. This paper studies the congestion behavior of IEEE802.11p/1609.4 based Medium Access Control by varying vehicle density in urban and highway conditions. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is the default medium access mechanism in WAVE MAC. The metrics chosen for evaluating the performance of CSMA/CA are the average end-to-end delay, average throughput, packet delivery ratio, packet loss ratio and the number of packets lost. The simulation is carried out for both urban and highway scenario under varying vehicle density and communication load. The Simulation is performed using Omnet++ and SUMO based veins framework. The simulation results show that under high vehicle density and high communication load, CSMA/CA fails to meet the required QoS.

On the Performance of IEEE 802.11p and LTE-V2V for the Cooperative Awareness of Connected Vehicles

To improve safety on the roads, next-generation vehicles will be equipped with short-range communication technologies. Many applications enabled by such communication will be based on a continuous broadcast of information about the own status from each vehicle to the neighborhood, often referred as cooperative awareness or beaconing. Although the only standardized technology allowing direct vehicle-to-vehicle (V2V) communication has been IEEE 802.11p until now, the latest release of long-term evolution (LTE) included advanced device-to-device features designed for the vehicular environment (LTE-V2V) making it a suitable alternative to IEEE 802.11p. Advantages and drawbacks are being considered for both technologies, and which one will be implemented is still under debate. The aim of this paper is thus to provide an insight into the performance of both technologies for cooperative awareness and to compare them. The investigation is performed analytically through the implementation of novel models for both IEEE 802.11p and LTE-V2V able to address the same scenario, with consistent settings and focusing on the same output metrics. The proposed models take into account several aspects that are often neglected by related works, such as hidden terminals and capture effect in IEEE 802.11p, the impact of imperfect knowledge of vehicles position on the resource allocation in LTE-V2V, and the various modulation and coding scheme combinations that are available in both technologies. Results show that LTE-V2V allows us to maintain the required quality of service at even double or more the distance than IEEE 802.11p in moderate traffic conditions. However, due to the half-duplex nature of devices and the structure of LTE frames, it shows lower capacity than IEEE 802.11p if short distances and very high vehicle density are targeted.

A cross-layer design for data dissemination in vehicular ad hoc networks

Data dissemination in vehicular ad hoc networks (VANETs) has attracted researchers’ attention in recent years. However, due to high vehicle density in urban areas and increasing data volume, wireless interference seriously impairs data dissemination performance of a VANET. To alleviate the interference problem, we propose a cross-layer design to exploit both spatial and temporal reusability of wireless spectrum in VANETs. In particular, the proposed cross-layer design integrates power control in the physical layer, time division in the MAC layer and data routing in the network layer. To implement the cross-layer design, we formulate an interference-aware power-control (IAPC) problem with the objective of maximizing data throughput in a VANET. For solving the IAPC problem, an integer linear programming formulation is proposed to derive the optimal solution. In addition, an efficient heuristic algorithm, named IAPC-Solver, is proposed to achieve a near-optimal solution. Extensive simulation experiments have been conducted on a widely adopted testbed, and the experimental results illustrate that the cross-layer design together with the proposed algorithms are effective for improving data dissemination performance of a VANET.

Comparison of Data Dissemination Protocols for Road Traffic Collecting Application in a Vehicular Ad hoc Network

Providing real-time road traffic information to drivers is a critical step to improve road traffic efficiency by allowing appropriate routes to be chosen. In a Vehicular Ad hoc Network (VANET), a query message can be disseminated along several road paths for collecting road traffic information. While several VANET protocols have been proposed to accomplish such task, they were evaluated in different settings, environments, and a limited scale. To gain better insights for actual deployment, it is necessary to explore their relative performance advantages and limitations. In this paper, we compare Slotted 1 persistence, Efficient Directional Broadcast (EDB), Data dissemination pRotocol In VEhicular networks (DRIVE), and Road Traffic Collecting (RTC) protocols under a large scale city networks, high vehicle density, multiple query sessions, and the presence of interfering background traffic. The evaluation focuses on the average percentage of targeted road segment coverage, the total number of transmitted messages, and the completion delay time. The results show that EDB outperforms other protocols in terms of the road segment coverage with highest number of transmitted messages while RTC yields a lower number of transmitted messages with less road segment coverage. However, EDB requires road-side units at every intersection and its performance dramatically drops under the failure of road-side units.

Adaptive beaconing for collision avoidance and tracking accuracy in vehicular networks

In vehicular networks, the exchange of beacons among neighboring vehicles is a promising solution to guarantee a vehicle’s safety. However, frequent beaconing under high vehicle density conditions will cause beacon collisions, which are harmful to a vehicle’s driving safety and the location tracking accuracy. We propose an ABIwRC (Adaptive Beaconing Interval with Resource Coordination) method for a highway scenario. Each vehicle broadcasts beacon interval requests, including the intervals needed for both the vehicle’s driving safety and location tracking accuracy. The RSU(Road Side Unit) allocates resources for a vehicle’s beaconing according to the requests from all vehicles and the interference relationship between the vehicles in adjacent RSUs. We formulate a resource allocation problem for maximizing the sum utility, which measures the satisfaction of vehicles’ requests. We then transform the optimization problem into a maximum weighted independent set problem, and propose an algorithm to solve this efficiently. Simulation results show that the proposed method outperforms the benchmark in terms of beacon reception ratio, vehicle driving safety, and location tracking accuracy.

Public service approach to car‐sharing in mid‐sized towns: the example of Belfort (France)

Car-sharing (CS) is an alternative to private cars able to change mobility customs and to participate in the greenhouse gas emission reduction. The administration board of the Belfort bus operator decided in January 2013 to build-up a visible and attractive CS service following a public service idea and integrated into the urban mobility offer, with significantly higher vehicle density and vehicle/inhabitants ratio than in the other French cities. This innovative approach resulted in a remarkably high ratio of nearly 42 members/1000 inhabitants in December 2016. In 2015, the service totalled >2300 clients, 33,000 rentals and 1.5 million kilometres after only 2 years running. These figures confirm the hypothesis that CS can be rapidly developed as a veritable alternative even in mid-sized towns. This article focuses on the design elements of the Belfort CS service as well as first analyses based on 2015 data and problems encountered.

Modelling unmanned aerial vehicles base station in ground‐to‐air cooperative networks

After disasters, road side units, which can provide wireless communications to vehicles, may fail due to physical damages or power outages. Vehicle-to-vehicle communication also may not perform well owing to lack of neighbours in low vehicle density scenario or collisions in high vehicle density circumstance which may happen in disaster areas. In this study, the deployment of unmanned aerial vehicles (UAVs) as flying base stations to improve connectivity among vehicles in disaster affected areas is analysed. First, the connectivity among vehicles as a function of the altitude of the UAV is derived. Furthermore, multiple UAVs scenario is analysed to determine the minimum number of UAVs needed to guarantee a target connectivity threshold among vehicles for a given geographical area and vehicle density. Numerical and simulation results verify that there exist optimal UAV altitudes for different scenarios as shown in the authors' analyses, and the simulation results also verify that the number of UAVs must be larger than a certain value to guarantee a target connectivity threshold among vehicles.

MODELING AND SIMULATION OF TRAFFIC FLOWS ON INCLINED ROAD DURING EVACUATION PROCESS OF THE VOLCANO DISASTER WITH FINITE DIFFERENCE METHOD

The research in this thesis was done to examine the model of traffic flow of volcanic disaster evacuation path for uphill and downhill roads. The assessment was focused on the area of disaster evacuation path from the Pante Raya Bener Meriah intersection to Takengon. This model is assessed for two different types of time when which a disaster occurs; the disaster occurred at night and the disaster occurred during the day, especially during peak hours (working hours). The model was developed with attention to the exixtence of inflow and outflow along the evacuation route. Furthermore, the model obtained is solved numerically by using finite difference method. The chosen approach of this method is upwind scheme with time and space steps using forward difference and backward difference. The solution of this model in the form of simulated vehicle density along evacuation pathways. The research conducted is in the form of a model of traffic flow on evacuation paths and restricted to the inflow and outflow without alternative path as well as the conditions of the road which are uphill and downhill, showed a high density of vehicles either at night or during the day. Uphill road conditions resulted in decreased vehicle speed and vehicle density will increase, while downhill road conditions resulted in increased vehicle speed and vehicle density will decrease, meaning that the road conditions which are uphill and downhill will greatly affect the process of evacuation. Degree vehicles of evacuation efficiency occuring at night without an alternative pathway produces a high efficiency so that it can be interpreted that the evacuation process in the evening was successful and runs better than the evacuation process during the day, and this is caused by the existence of vehicles on the road evacuation process started thus affecting the efficiency levels. Keywords : Traffic flows, finite difference method, upwind scheme method, forward difference, backward difference, greenshield method, uphill road, downhill road.

The mobile monitoring of black carbon and its association with roadside data in the Chinese megacity of Shanghai.

High-level black carbon (BC) pollution is associated with traffic emissions in metropolitan areas with high vehicle density. Mobile monitoring was conducted to assess the in-vehicle BC exposure on three backbone ring roads (inner, middle, and outer ring roads) on October 14 and October 18, 2015 in Shanghai. Ambient BC monitoring was also simultaneously conducted in three fixed roadside stations from October 14 to October 20, 2015. Results of the mobile monitoring showed median BC personal exposure concentrations ranging from 5.0μgm-3 on the inner ring road to 13.5μgm-3 on the outer ring road. The ambient BC concentrations during the entire observation period showed an arithmetic mean and a standard deviation of 3.5±2.9μgm-3. The correlation analysis of urban roadside monitoring (Caoxi Road and South Zhongshan Road) and personal data showed a high and significant correlation. The results of this study highlight the critical level of BC pollution in Shanghai and facilitate the development of evidence-based public health interventions and control strategies to prevent the adverse health effects of BC pollution.

An Efficient Channel Access Scheme for Vehicular Ad Hoc Networks

Vehicular Ad Hoc Networks (VANETs) are getting more popularity due to the potential Intelligent Transport Systems (ITS) technology. It provides many efficient network services such as safety warnings (collision warning), entertainment (video and voice), maps based guidance, and emergency information. VANETs most commonly use Road Side Units (RSUs) and Vehicle-to-Vehicle (V2V) referred to as Vehicle-to-Infrastructure (V2I) mode for data accessing. IEEE 802.11p standard which was originally designed for Wireless Local Area Networks (WLANs) is modified to address such type of communication. However, IEEE 802.11p uses Distributed Coordination Function (DCF) for communication between wireless nodes. Therefore, it does not perform well for high mobility networks such as VANETs. Moreover, in RSU mode timely provision of data/services under high density of vehicles is challenging. In this paper, we propose a RSU-based efficient channel access scheme for VANETs under high traffic and mobility. In the proposed scheme, the contention window is dynamically varied according to the times (deadlines) the vehicles are going to leave the RSU range. The vehicles with shorter time deadlines are served first and vice versa. Simulation is performed by using the Network Simulator (NS-3) v. 3.6. The simulation results show that the proposed scheme performs better in terms of throughput, backoff rate, RSU response time, and fairness.

The Trap Coverage Area Protocol for Scalable Vehicular Target Tracking

Vehicle target tracking is a sub-field of increasing and increasing interest in the vehicular networking research area, in particular for its potential application in dense urban areas with low associated costs, e.g., by exploiting existing monitoring infrastructures and cooperative collaboration of regular vehicles. Inspired by the concept of trap coverage area, we have originally designed and implemented an original protocol for vehicle tracking in wide-scale urban scenarios, called TCAP. TCAP is capable of achieving the needed performance while exploiting a limited number of inexpensive sensors (e.g., public-authority cameras already installed at intersections for traffic monitoring), and opportunistic vehicle collaboration, with high scalability and low overhead if compared with state-of-the-art literature. In particular, the wide set of reported results show i) the suitability of our TCAP tracking in the challenging urban conditions of high density of vehicles, ii) the very weak dependency of TCAP performance from topology changes/constraints (e.g., street lengths and speed limits), iii) the TCAP capability of self-adapting to differentiated runtime conditions.

Delay-Optimal Virtualized Radio Resource Scheduling in Software-Defined Vehicular Networks via Stochastic Learning

Due to the high density of vehicles and various types of vehicular services, it is challenging to guarantee the quality of vehicular services in current Long-Term Evolution (LTE) networks in a cost-efficient manner. Fortunately, with the development of fifth-generation (5G) technology, the installation of a large number of small cells is foreseen as one of the practical ways to achieve the low-delay requirement in vehicular environments. However, it may cause a huge operating expense and capital expenditure to mobile network operators due to the limited backhaul capacity and the explosion of signaling. In this paper, we integrate software-defined networking and radio resource virtualization into an LTE system for vehicular networks, i.e., software-defined heterogeneous vehicular network (SERVICE) . Based on this proposed system framework, a delay-optimal virtualized radio resource scheduling scheme is proposed via stochastic learning. The delay optimal problem is formulated as an infinite-horizon average-cost partially observed Markov decision process (POMDP). Then, an equivalent Bellman equation is derived to solve it. The proposed scheme can be divided into two stages, i.e., macro virtualization resource allocation (MaVRA) and micro virtualization resource allocation (MiVRA). The former is executed based on large timescale variables (traffic density), whereas the latter is operated according to short timescale variables (channel state and queue state). Simulation results show that the proposed scheme outperforms traditional schemes.

Estimating PM2.5-associated mortality increase in California due to the Volkswagen emission control defeat device

The Volkswagen Group of America (VW) was found by the US Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) to have installed “defeat devices” and emit more oxides of nitrogen (NOx) than permitted under current EPA standards. In this paper, we quantify the hidden NOx emissions from this so-called VW scandal and the resulting public health impacts in California. The NOx emissions are calculated based on VW road test data and the CARB Emission Factors (EMFAC) model. Cumulative hidden NOx emissions from 2009 to 2015 were estimated to be over 3500 tons. Adult mortality changes were estimated based on ambient fine particulate matter (PM2.5) change due to secondary nitrate formation and the related concentration-response functions. We estimated that hidden NOx emissions from 2009 to 2015 have resulted in a total of 12 PM2.5-associated adult mortality increases in California. Most of the mortality increase happened in metropolitan areas, due to their high population and vehicle density.

Evaluation of some heavy metals loading in dust fall of three universities motor parks in Western Nigeria

The high density of vehicles that run to and fro University campus to town has become of great concern for assessment of health status of the ambient air around the Universities motor parks. Moreover, some of the University’s parks are unpaved while the paved ones are old and unmaintained. Dust fall samples in parks of Universities of Ilorin, Ibadan and Kwara State University were collected for five months spanning from 1st November 2014 to 31st March, 2015 using open bucket sampler based on ASTM D 1739 of 1998 (2010). A 0.1 g of dust sample was digested with 20 ml of HNO3, HClO4 and HF in ratio of (3:2:1) respectively and heavy metals (Mn, Cu, Zn, Cd, Pb, and Ni) were analysed using atomic absorption spectrophotometer (Buck Scientific model 210 VGP). Results of heavy metal concentrations showed decrease in the following order: 1479.75, 1255.68, 241.50, 128.00, 85.25, and 9.63 mg/kg for Mn, Zn, Pb, Ni, Cu and Cd respectively for University of Ibadan. The decreased in concentrations of heavy metals obtained for University of Ilorin motor park dust-fall were found to be 1145.75, 797.75, 219.63, 133.51, 58.25 and 23.13 mg/kg for Mn, Zn, Pb, Ni, Cu and Cd respectively. For Kwara State University, decrease in the following order: 778.5, 323.88, 259.38, 101.38, 34.38, and 4.63 mg/kg for Mn, Zn, Pb, Ni, Cu and Cd respectively were obtained. Generally for the three sites used, the heavy metal concentrations decreased in the following order: Mn>Zn>Pb>Ni>Cu>Cd. This implies that dust-fall in the parks are heavily loaded with some heavy metals that are of concentrations above Romania standard threshold limit for Cd and Pb while concentration values obtained for Ni are higher than US- EPA values (75 mg/kg). The regulatory agent or management should ensure that the roads are paved and there should be intermittent wetting of the roads with water.Keywords: Dust Fall; Heavy Metals; University Motor Parks

A Street-Centric Routing Protocol Based on Microtopology in Vehicular Ad Hoc Networks

In a vehicular ad hoc network (VANET), high mobility and uneven distribution of vehicles are important factors affecting the performance of routing protocols. The high mobility may cause frequent changes of network topology, whereas the uneven distribution of vehicles may lead to routing failures due to network partition; even high density of vehicles may cause severe wireless channel contentions in an urban environment. In this paper, we propose a novel concept called the microtopology (MT), which consists of vehicles and wireless links among vehicles along a street as a basic component of routing paths and even the entire network topology. We abstract the MT model reflecting the dynamic routing-related characteristics in practical urban scenarios along streets, including the effect of mobility of vehicles, signal fading, wireless channel contention, and existing data traffic. We first analyze the endside-to-endside routing performance in an MT as a basis of routing decision. Then, we propose a novel street-centric routing protocol based on MT (SRPMT) along the streets for VANETs. Simulation results show that our proposed SRPMT protocol achieves higher data delivery rate and shorter average end-to-end delay compared with the performance of greedy perimeter stateless routing (GPSR) and greedy traffic-aware routing (GyTAR).

Screening of short-lived climate pollutants in a street canyon in a mid-sized city in Brazil

Black carbon (BC) and tropospheric ozone (O3) are two main short-lived climate pollutants also linked to health effects. They are ubiquitous in street canyons, since this environment is a hotspot for traffic-related pollutants due to their particular airflow characteristics, location within the cities and the high density of vehicles and population.We report on BC and O3 concentrations measured in a Brazilian city in November 2014. Measurements of BC at 880 nm wavelength were conducted in a street canyon on the north and south façades and at rooftop level (7 wavelengths, including 880 nm) whereas O3 was recorded only on the south façade. Concurrent meteorological data were gathered at a suburban and a rooftop sites.Clear diurnal patterns were found for BC related to traffic emissions and atmospheric mixing conditions. Ozone peaked in the afternoon in response to maximum photochemical production and at night most likely linked to vertical and/or horizontal transport. By using conditional bivariate probability functions, we identified on-road traffic as the main local source for BC during daytime, and at night an intermittent signal was associated with local waste and biomass burned on the city's outskirts. A complementary air backward trajectory analysis helped conclude that locally produced O3 was enhanced by regional transport from large cities and/or biomass smoke.Mitigation strategies for BC and O3 depletion should target the vehicle fleet, particularly diesel buses, reduction of biomass and waste burning at local level, and decrease of open biomass burning in large areas in Brazil and neighbor countries.

A Bandwidth-Efficient Dissemination Scheme of Non-Safety Information in Urban VANETs.

The recent release of standards for vehicular communications will hasten the development of smart cities in the following years. Many applications for vehicular networks, such as blocked road warnings or advertising, will require multi-hop dissemination of information to all vehicles in a region of interest. However, these networks present special features and difficulties that may require special measures. The dissemination of information may cause broadcast storms. Urban scenarios are especially sensitive to broadcast storms because of the high density of vehicles in downtown areas. They also present numerous crossroads and signal blocking due to buildings, which make dissemination more difficult than in open, almost straight interurban roadways. In this article, we discuss several options to avoid the broadcast storm problem while trying to achieve the maximum coverage of the region of interest. Specifically, we evaluate through simulations different ways to detect and take advantage of intersections and a strategy based on store-carry-forward to overcome short disconnections between groups of vehicles. Our conclusions are varied, and we propose two different solutions, depending on the requirements of the application.

Support for vehicle-to-everything services based on LTE

Vehicular applications and communications technologies are often referred to as vehicle-to-everything (V2X), which is classified into four different types: vehicle-to-vehicle (V2V), vehicle- to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P) [1]. V2X related research projects, field tests, and regulatory work have been promoted in different countries and regions. In May 2015, the Ministry of Industry and Information Technology (MIIT) of China explained national strategies, Made in China about intelligent connected vehicles. In 2020 and 2025, the overall technology and key technologies for intelligent driver assistance and automatic driving will be available in China, respectively [2]. V2X solutions are the critical technologies to support the realization of such visions. Although IEEE 802.11p has been selected as the technology for V2X communications in some countries such as the United States and in Europe, the intrinsic characteristics of IEEE 802.11p have confined the technology to support low latency with high reliability [3, 4]. Standardization of Long Term Evolution (LTE)-based V2X is being actively conducted by the Third Generation Partnership Project (3GPP) to provide the solution for V2X communications that benefit from the global deployment and fast commercialization of LTE systems. Because of the wide deployment of LTE networks, V2I and V2N services can be provided with high data rate, comprehensive quality of service (QoS) support, ubiquitous coverage, and high penetration rate [5]. Meanwhile, LTE can be extended to support V2V direct communications based on device-to-device (D2D) sidelink design to satisfy the QoS requirements, such as low latency, high reliability, and high speed in the case of high vehicle density [6].