High Traffic Flow Research Articles

Equivalent noise level response to number of vehicles: a comparison between a high traffic flow and low traffic flow highway in Klang Valley, Malaysia

Although much research on road traffic noise has found that noise level increase are influenced by driver behaviour and source- receiver distance, little attention has been paid to the relationship between noise level and total number of vehicles on the road. In this study, five days measurement of noise level during peak hour and off peak hour has been carried out at two types of highways; high traffic flow highway (Sungai Besi Expressway)and low traffic flow highway(Duke Highway). Simultaneously, the number of vehicles passing the measurement point were recorded for every 15 minutes. Findings indicated that heavy traffic flow highway recorded higher noise level compared to low traffic flow highway. It was due to the higher number of vehicles on the heavy traffic flow highway than low traffic flow highway. Other than that, certain particular number of vehicles, noise level keeps stabilization.

Its System to Manage Parking Supply: Considerations on Application to the “Ring” in the City of Brescia

Brescia’s downtown is outlined by link roads built up at the Venetian walls, known as “Ring. The “Ring” is characterized by high traffic flows, as well as by the presence of several paid parking lots located on and off street. Furthermore, several facilities are located on these link roads. Nowadays city of Brescia is equipped with an ITS system able to manage off street parking spaces, allowing the share of information about parking availability to potential users, through the use of variable message panels. The parking supply issue and its management are strongly felt by citizens, as well as many other cities communities, whether European or not. This contribution aims to encourage an integration of the existing ITS system for the off street parking management with additional devices, which allow to manage also the on street paid parking supply located on “Ring” roads. The minimization of so-called “shared traffic” component of traffic flows, as well as the increase of road safety, in the context of a medium-sized Italian city are the main objectives of the ITS system integration. ITS asset chosen for the Brescia case study springs from the analysis of some non-European experiences about on street parking management (for example, San Francisco and Boston) and certainly can be considered suitable for the parking supply management of the whole city. It could become the main starting point in Italian cities for the application of performance based parking pricing, widely experienced in many U.S. cities.

Study on Distance Control System of Urban Traffic

Because of the characteristics of the urban traffic, which has higher traffic flow, low speed and flexible vehicle driving behaviors, the driving state of the vehicles must be changed frequently, so distance control system of urban traffic is put forward. The thesis built the best acceleration prediction, shortest security distance model, fuzzy controller and the whole vehicle model, and so on. Then the thesis made a simulation on distance control system of urban traffic, using Matlab/Simulink software, got some curve of different working situation.

Cascade defense in urban road network by inserting modular topologies

Purpose – By aiming at defending cascade failures effectively, the purpose of this paper is to present a strategy of inserting modular topologies into urban road network through reducing the burdens of critical components with too much traffic flow. Design/methodology/approach – Each module is considered as a small-world random network, which is inserted into the initial Barabási-Albert scale-free network. Based on the user-equilibrium assignment, the strategy searches for remote nodes with low betweeness and flow in the network, and sets these nodes to be connected with the modular topologies. In this sense, the inserted modules are supposed to attach to the nodes with lower intensity of shorter path, and avoid bringing more impact to the nodes with higher betweeness and traffic flow. By using efficiency as the measurement of cascading failures, the performance of the networks generated through the strategy is tested. Findings – The results show that the performance of the strategy is sensitive to the average degree of the inserted modular, and the modular size with a better effect on reducing the size of cascading failures or delaying the time of breakdown, while the other factors (e.g. the rewired probability) present few differences among various values. Meanwhile, it is found that the importance-based attachment mechanism has a better effect on preventing the cascading failures, especially delaying the step time of the larger reduction. Practical implications – The strategy aims at alleviating the burdens in critical components to prevent the cascading failures of the network, and provides practical guidance on the decision of the urban road network evolving process. Originality/value – An effective strategy for cascade defense in urban road network is proposed in this paper.

Differences between sound pressure levels measured outdoors in three heights commonly used in environmental noise impact assessment

In environmental acoustics, outdoor sound pressure level can be measured at different heights over ground. ISO 1996 recommends measurements at 4 m, which is representative for multi-storey residential areas and in accordance with EU directives for noise map modeling. For other areas ISO 1996 recommends measurements 1.5 m over ground, a height that corresponds to the median height of adults ears. In Brazil, 1.2 m are commonly used for outdoor measurements and noise map calibrations as this height is recommended by the Brazilian standard NBR 10.151-2000. The goal of this work is to investigate the relationship between SPL measurements obtained at these three heights. Measurements were taken close to roads at a university campus, roads that in some cases have high traffic flows. The differences between measured A-weighted equivalent SPLs (LAeq) at the different heights were statistically analyzed. Difference distributions were found to be closely to normal distribution with some outliers. Mean values of the SPL differences remained below 3 dB. From the data obtained, it seems acceptable to calibrate a noise map model at a different height from the measured one using the mean difference as a correction term.

Calculation model of road traffic noise annoyance rate in urban areas

This paper presents a calculation model for road traffic annoyance based on traffic flow counting, road traffic noise emission measures and public surveys held in the urban area of inner Budapest, Hungary. Based on the research results a new model for the rate of highly annoyed of road traffic noise annoyance was determined, the subjective response of a person to road traffic noise emissions. Exposure to high road traffic noise may deteriorate everyday life and human well-being especially in urban areas with high traffic flow. With the model developed the rate of high annoyance can be predicted for urban traffic circumstances, for a given noise level. This prediction may help authorities to decide whether a road traffic noise complaint is justified or not and whether further measurements are necessary.

Polycyclic aromatic hydrocarbon contamination in an urban area assessed by Quercus ilex leaves and soil

We investigated the PAH contamination of Naples urban area, densely populated and with high traffic flow, by analyses of environmental matrices: soil and Quercus ilex leaves. Being some PAHs demonstrated to have hazardous effects on human health, the accumulation of carcinogenic and toxic PAHs (expressed as B(a)Peq) was evaluated in the leaves and soil. The main sources of the PAHs were discriminated by the diagnostic ratios in the two matrices. The urban area appeared heavily contaminated by PAHs, showing in soil and leaves total PAH concentrations also fivefold higher than those from the remote area. The soil mainly accumulated heavy PAHs, whereas leaves the lightest ones. Median values of carcinogenic PAH concentrations were higher in soil (440ngg(-1)d.w.) and leaves (340ngg(-1)d.w.) from the urban than the remote area (60 and 70ngg(-1)d.w., respectively, for soil and leaves). Also, median B(a)Peq concentrations were higher both in soil and leaves from the urban (137 and 63ngg(-1)d.w., respectively) than those from the remote area (19 and 49ngg(-1)d.w., respectively). Different from the soils, the diagnostic ratios found for the leaves discerned PAH sources in the remote and urban areas, highlighting a great contribution of vehicular traffic emission as main PAH source in the urban area.

Survey of (PM2.5) Concentrations in Sari's City Center in 2010

Background and purpose: Because of the high traffic flow in the city center in Sari, a walk through survey indicated that the PM2.5 concentrations are likely to be higher than the standards. This study was carried out to determine the level of PM2.5 at the streets' curbsides in the city center in Sari. Materials and Methods: In this cross-sectional study the PM2.5 concentrations were measured in 185 monitoring stations at the curbsides of four main streets in the Sari city centre. 5550 10-s samples were collected using a real time particle monitor. A questionnaire was used to record air pollution related information and data were analyzed by descriptive statistic and ANOVA tests. Results: Mean of PM2.5 concentration was 83µgm-3 and it was two times more than the national one and EPA recommended 24- hour standard (35µgm-3). This study showed that mean of PM2.5 concentration at the street during traffic rush hours in the morning and evening were higher than those measured in the afternoon. Conclusion: Because of the high concentration of PM2.5 in the Sari’s city centre that resulted in this study, the 24- hour PM2.5 concentrations are likely to be higher than standards in some days in the city centre in Sari. Therefore, monitoring and control of air pollution are recommended in this city. [*Mohammadyan M. Sojudi L. Survey of PM2.5 Concentrations in Sari's City Center in 2010. 2014;2(1):30-36] http://jhs.mazums.ac.ir

My Traffic Manager

Abstract We propose the idea of using the drivers themselves as sources of traffic information, providing a simple system interface on a mobile device to alert the user of possible traffic situations. Allied to this concept is a system, which based on information sent by drivers, identifies occurrences relating to traffic and again establishes communication with the drivers, this time to let them know these same conditions on their route. My Traffic Manager (MTM), cooperative system of traffic impact, aims to develop and provide a traffic information system that takes advantage of a collaborative network established between users, allowing the user to avoid roads with higher traffic flow, targeting the Android operating system and directly interacting with the existing Google Maps platform.

Fuzzy Logic Based Rate Control Scheme for ODMRP in Mobile Ad hoc Networks

On Demand Multicast Routing Protocol (ODMRP) is a popular solution designed for ad hoc networks with mobile hosts. Its efficiency, simplicity, and robustness to mobility render it one of the most widely used multicast routing protocols in Mobile Ad hoc NETworks (MANET). In ODMRP, there is no input rate control for upper layer traffic. So, it's possible that high dense traffic flow causes congestion in networks. In this work, an enhancement to ODMRP is proposed referred to as fuzzy logic based Rate Control ODMRP (FRC-ODMRP). FRC-ODMRP attempts to adapt the arrival rate from upper layers to the state in the network by using feedback information from receivers of the multicast group. Accordingly, source comes up with a decision whether to increase or decrease its transmission rate based on information collected from the receivers. In this research, delay and packet delivery ratio reconsidered as indicators of congestion in addition to number of received packets. Simulation results demonstrate that FRC-ODMRP achieves significant performance improvements in comparison to conventional ODMRP and QoS-ODMRP. Indeed, it efficiently handles simultaneous traffic flows such that no one could dominate available bandwidth of networks.

Perspective of Adaptive CN System for Forecasting Congestion of Road Traffic Flow

Basing upon the Weber-Fechner Law with respect to the stimulus (distance-headway) to the vehicle driver and the driver’s sensation (speed), the characteristic speed Vβ is defined, which is the critical vehicles flow speed just before going to congestion in road traffic flow. From the information of real time measurement of traffic flow speed (V) and time-headway (T) at the specific positions along the road, the value of Vβ is calculated and used for forecasting the flow. Discussed is how to use each Vβ to forecast the congestion. The CN system devoted to the management of road traffic flow is proposed. The idea may contribute not only to easing the traffic flow but also to optimizing it to get high efficient traffic flow.

Rapid Dissemination of Public Safety Message Flows in Vehicular Networks

We consider a Road Side Unit (RSU) that aims to broadcast critical public safety message flows to vehicles that travel along a linear highway. The RSU is able to transmit such message flows directly to only a limited group of vehicles travelling in its close vicinity. To assure delivery of these messages to all other vehicles traveling along the highway, we make use of a Vehicular Ad Hoc Network (VANET) system to provide vehicle-to-vehicle multi-hop transport of these messages. We propose a VANET networking scheme that is identified as a Vehicular Backbone Network (VBN), under which vehicles that are located close to properly selected nominal positions are elected to serve as Relay Nodes (RNs). We study the optimal cross-layer design of such a network system, by presenting an analytical model to jointly select the operational data rate, scheduling mechanism and the inter-RN targeted distance levels. We show that a high level of coverage of highway vehicles, coupled with very low incurred queueing delays, can be achieved by employing a flow admission control mechanism at the source. We consider a high intensity vehicular traffic flow regime under which vehicles that are elected to serve as RNs are generally located close to designated nominal positions, as well as lower rate stochastic traffic flow conditions. Furthermore, we demonstrate the capability of the system, when properly configured, to employ a vehicular Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA) access scheme to well emulate the operations of the system when managed by the use of spatial-reuse Time Division Multiple Access (TDMA) scheduling scheme. Our mathematical analyses and designs are well confirmed through the execution of system simulation analyses.

Mobile Particle and NOx Emission Characterization at Helsinki Downtown: Comparison of Different Traffic Flow Areas

A two weeks measurement campaign by a mobile laboratory van was performed at downtown Helsinki, Finland, in winter 2010. The characteristics of air pollutants such as fine particles in the size ranges of 7–40 nm (Np40) and 40–1000 nm (Np1000), black carbon (BC), fine particle mass (PM2.5), as well as gaseous compounds NO, NO2, NOx, CO and CO2 were studied. The statistical analysis showed that the air pollution conditions strongly depended on the traffic flow area; therefore, the street sections were classified as high traffic flow areas (HTF1-HTF4), low traffic flow areas (LTF1-LTF5), and urban background areas (BG1-BG3). Large variation of particle emissions was observed, and the momentary peak particle concentrations were 8 × 105 cm–3. At the HTF areas exhaust emissions followed clearly daily average heavy duty vehicle counts rather than the average daily vehicle counts. Higher correlation coefficients were found between CO2 and NO than between CO2 and Ntot. The dispersion studies indicated that the air pollution conditions strongly improved from high traffic flow areas to low traffic flow areas. Therefore, proper city planning and locating, for example, cycle tracks, schools and hospitals farther from busy city streets might significantly reduce exposure risk for humans.

Modeling trailer-traffic flow on a Kenyan highway

Traffic flow modelling is studied in order to ease congestion on roads. However, congestion is also caused by irregular occurrences, such as traffic accidents, poor roads, vehicle disablement, spilled loads and hazardous materials. This study explored the area of poor roads which was considered to be as a result poor planning for road network repairs. Traffic flow was categorized to be either in low, intermediate, or high volume. Modelling for every flow required a different distribution namely the Exponential, Pearson type III and Normal distributions for low, intermediate and high traffic flow volume respectively. However, we modelled the trailers traffic flow using a model that covered all the 3 states, in this case,the Pearson type III distribution. Further,we investigated the shape of the probability distribution function assumed by the trailers. After data collection,extraction and analysis, Pearson type III distribution model was calibrated to fit. Lastly, Kolmogorov-Smirnov and Chi-square tests of goodness of fit was run on the observed data. Although, the data was also fitted into Normal, Erlang, Exponential, Beta and Gamma Distributions, Pearson type III distribution provided the best fit. Mathematics Subject Classification: 49K05 Keywords: Traffic flow, Modelling, Congestion, Road network, Trailers, Probability distribution Language: en

Exploring Bias in Traffic Data Aggregation Resulting from Transition of Traffic States

Transportation engineers and researchers heavily use traffic data, which are generally aggregated by predetermined time intervals (e.g., 5 to 15 min). The aggregation process often discards essential information of traffic state transition (e.g., breakdowns). However, the transition of traffic conditions within an aggregation interval is not well understood. This study explored traffic state transition from uncongested to congested regimes that occurred within a predetermined time interval. From two urban freeway locations in Norfolk, Virginia, traffic data archived at 15-min intervals were obtained. A heuristic method based on a Gaussian mixture model was developed to detect the aggregate traffic data that exhibit the transition of traffic states as well as to partition the data statistically into uncongested and congested traffic states. Results show a substantial difference in travel speed (approximately 20 mph) between the two states. In addition, these results illustrate that aggregating these different traffic conditions can cause substantial traffic data aggregation bias by lowering travel speed and flow rates, especially in high traffic flow situations. Finally, new insights into valid traffic data aggregation and speed–flow–concentration relationship development are discussed.

Payment mechanisms for winter road maintenance services

In countries with severe winters a major part of the annual budget for road maintenance is allocated on performance of winter road maintenance tasks. Finding appropriate remuneration forms to compensate entrepreneurs for performed road measures during winter is not an easy task in order to minimise or eliminate disputes and satisfy both client organisations and contractors. On the other hand improper reimbursement models lead either to the client’s annual budget imbalance due to unnecessary cost overruns or affect contractor’s cash-flow. Such cases in turn affect just-in-time winter road maintenance and then traffic safety. To solve such problems, a number of countries in cold regions like Sweden have developed different remuneration models based more on weather data called Weather Index. Therefore the objective of this paper is to investigate and evaluate the payment models applied in Sweden. The study uses a number of approaches namely; domestic questionnaire survey, analysis of a number of contract documents, a series of meetings with the project managers and an international benchmarking. The study recognised four remuneration models for winter maintenance service of which one based on weather data statistics. The study reveals the payment model based on weather data statistics is only applied for the roads with higher traffic flow and the model generates most uncertainty.

A computer model for optimizing the location of natural gas fueling stations

High levels of fine particulate matter and ozone in many major cities are causing increased respiratory problems, increased asthma attacks and premature death. Natural gas vehicles have been reported to emit up to 95% less particulate matter than diesel powered vehicles and up to 90% less ozone-producing carbon monoxide and reactive hydrocarbons. The adoption of natural gas vehicles, therefore, could play a large role in improving air quality in many cities. Because of the many costs associated with the introduction of a new fueling infrastructure, optimum distribution of fueling stations will play a major role in widespread use of natural gas vehicles, especially in the early stages of market penetration. A model was developed that can be used to optimize fueling station placement-based on traffic volume using a Monte Carlo algorithm. In particular, the Monte Carlo method allows for the placement of the fueling stations based upon their proximity to high volume traffic flow and the placement of all the fueling stations are optimized simultaneously. Traffic volume data from Pittsburgh, PA was used in the model simulations.

Evaluation of climatic factors based on the mechanistic-empirical pavement design guide

In this paper, a procedure for evaluating the effects of climate on pavement performance in Italy is proposed. To characterize the Italian territory nine different simulated scenarios have been used. These scenarios were obtained by combining three different situations of latitude (North, Central and South) with three conditions of altitude (high, medium, low altitude). For each of these scenarios, some configurations, proposed by the Italian CNR road pavement design catalog with medium and high traffic flow, were verified using the Mechanistic-Empirical Pavement Design Guide. The results obtained showed that the Italian CNR road pavement design catalog has a limited reliability.

Complex Anthropogenic Sources of Platinum Group Elements in Aerosols on Cape Cod, USA

Platinum group elements (PGE) of anthropogenic origin have been reported in rainwater, snow, roadside soil and vegetation, industrial waste, and urban airborne particles around the world. As recent studies have shown that PGE are bioavailable in the environment and pose health risks at chronic levels, the extent of PGE pollution is of global concern. In this study, we report PGE concentrations and osmium isotope ((187)Os/(188)Os) ratios of airborne particles (particulate matter, PM10) collected in Woods Hole, a small coastal village on Cape Cod, Massachusetts, U.S.A. The sampling site is more than 100 km away from the nearest urban centers (Boston, Providence) and has no large industrial emission center within a 30 km radius. The study reveals that, although PGE concentrations in rural airborne particulate matter are orders of magnitude lower than in urban aerosols, 69% of the total osmium is of anthropogenic origin. Anthropogenic PGE signatures in airborne particles are thus not restricted to large cities with high traffic flows and substantial industries; they can also be found in rural environments. We further conclude that the combination of Pt/Rh concentration ratios and (187)Os/(188)Os composition can be used to trace PGE sources. The Pt/Rh and (187)Os/(188)Os composition of Woods Hole aerosols indicate that the anthropogenic PGE fraction is primarily sourced from ore smelting processes, with possible minor contributions from fossil fuel burning and automobile catalyst-derived materials. Our results further substantiate the use of (187)Os/(188)Os in source apportionment studies on continental scales.

A real-time crash prediction model for the ramp vicinities of urban expressways

Ramp vicinities are arguably the known black-spots on urban expressways. There, while maintaining high speed, drivers need to respond to several complex events such as maneuvering, reading road signs, route planning and maintaining safe distance from other maneuvering vehicles simultaneously which demand higher level of cognitive response to ensure safety. Therefore, any additional discomfort caused by traffic dynamics may induce driving error resulting in a crash. This manuscript presents a methodology for identifying these dynamically forming hazardous traffic conditions near the ramp vicinities with high resolution real-time traffic flow data. It separates the ramp vicinities into four zones – upstream and downstream of entrance and exit ramps, and builds four separate real-time crash prediction models. Around two year (December 2007 to October 2009) crash data as well as their matching traffic sensor data from Shibuya 3 and Shinjuku 4 expressways under the jurisdiction of Tokyo Metropolitan Expressway Company Limited have been utilized for this research. Random multinomial logit, a forest of multinomial logit models, has been used to identify the most important variables. Finally, a real-time modeling method, Bayesian belief net (BBN), has been employed to build the four models using ramp flow, flow and congestion index in the upstream and flow and speed in the downstream of the ramp location as variables. The newly proposed models could predict 50%, 42%, 43% and 55% of the future crashes with around 10% false alarm for the downstream of entrance, downstream of exit, upstream of entrance and upstream of exit ramps respectively. The models can be utilized in combination with various traffic smoothing measures such as ramp metering, variable speed limit, warning messages through variable message signs, etc. to enhance safety near the ramp vicinities.