Showing papers in "Transport in 2013"

Short term traffic flow prediction in heterogeneous condition using artificial neural network

Abstract: Traffic congestion is one of the main problems related to transportation in developed as well as developing countries. Traffic control systems are based on the idea to avoid traffic instabilities and to homogenize traffic flow in such a way that risk of accidents is minimized and traffic flow is maximized. There is a need to predict traffic flow data for advanced traffic management and traffic information systems, which aim to influence traveller behaviour, reducing traffic congestion and improving mobility. This study applies Artificial Neural Network for short term prediction of traffic volume using past traffic data. Besides traffic volume, speed and density, the model incorporates both time and the day of the week as input variables. Model has been validated using actual rural highway traffic flow data collected through field studies. Artificial Neural Network has produced good results in this study even though speeds of each category of vehicles were considered separately as input variables.

The use of AHP and rank correlation methods for determining the significance of the interaction between the elements of a transport system having a strong influence on traffic safety

Abstract: A system of road transport involves vehicles, roads, traffic participants and freight that therefore closely interact. The interaction between these material elements takes place in an external environment. The process of transportation is aimed at achieving some positive results, which could increase the efficiency of the Transport System (TS). However, negative effects such as a high accident rate cannot be avoided. The road accident rate is determined by the properties of the material elements of the TS and the parameters of their interaction. Their impact on the traffic accident rate cannot be determined by a planned experiment. They also cannot be compared quantitatively, because their units of measurement are different. The paper presents a detailed description of nine types of the interaction between TS elements belonging to three various levels. The data was given to 16 transport engineering specialists as a questionnaire for expert evaluation. The paper offers a logical control methodology for fi...

Developing a new hybrid MCDM method for selection of the optimal alternative of mechanical longitudinal ventilation of tunnel pollutants during automobile accidents

Abstract: Breathable air inside the tunnel is an undeniable necessity and beside natural ventilation, the tunnel should be reliably organized, to automatically provide healthy air under different conditions Among methods of tunnel ventilation, longitudinal and transverse modes are the most common mechanical methods This research is focused on selection of the optimal method for mechanical longitudinal ventilation of tunnel pollutants from four presented models In terms of this research, the authors used SWARA (Step-wise Weight Assessment Ratio Analysis) as one of the most versatile MCDM (Multiple-Criteria Decision-Making) methods for managerial decision making in complex situations with multiple and varied measures Fourteen experts of different fields were involved The research model was established based on expert ideas and the following criteria: smoke control (C 1), safety level (C 2), design complexity (C 3), investment costs (C4), increasing concentration of pollutants until portal (C5), smoke la

A modeling government revenue guarantees in privately built transportation projects: a risk-adjusted approach

Abstract: Countries around the world have welcomed Public Private Partnerships (PPPs) as an alternative to finance infrastructure. For strategic projects with high demand uncertainty, a government may decide to provide a concessionaire with a Minimum Revenue Guarantee (MRG) to mitigate revenue risk and to help enhance the project's credit, thereby reducing the financing costs of the project. However, government revenue guarantees can pose fiscal risks to the issuing government if too many significant claims are redeemed at the same time. This undesirable circumstance can be exacerbated during an economic recession in which tax revenues are low and the costs of subsidies are potentially higher than expected. This paper presents a new model of government revenue guarantees by which revenue guarantee thresholds are adjusted over time to reflect the inter-temporal risk profiles of the project. Revenue risk is modeled using a stochastic process called the Variance Model. Then, revenue shortfalls and revenue exc...

Efficiency evaluation in public road transport: a stochastic frontier analysis

Abstract: This paper measures the technical efficiency of 54 public road transport operators and investigates the degree to which various factors influence efficiency levels in these firms. The study makes an attempt to provide an overview of the general status of different operators in 18 countries. Stochastic Frontier Analysis (SFA) methods are applied to our sample over a twelve year period from 2000 to 2011. To our knowledge, this is the first comprehensive analysis of technical efficiency of public road transport operators in 18 countries using parametric method. Our empirical results indicate that investment, operating profit and firm size have a significant influence on technical efficiency levels. We find that technical efficiency level of public road transport operators varies between 0.458 and 0.95. We also observe that large-size operators with more investment capacity tend to be more technically efficient than small-size operators. Finally, we find that operators from developed countries are tec...

Knowledge discovery and data mining in pavement inverse analysis

Abstract: This paper describes the use of data mining tools for predicting the non-linear layer moduli of asphalt road pavement structures based on the deflection profiles obtained from non-destructive deflection testing. The deflected shape of the pavement under vehicular loading is predominantly a function of the thickness of the pavement layers, the moduli of individual layers, and the magnitude of the load. The process of inverse analysis, more commonly referred to as ‘backcalculation’, is used to estimate the elastic (Young's) moduli of individual pavement layers based upon surface deflections. A comprehensive synthetic database of pavement response solutions was generated using an advanced non-linear pavement finite-element program. To overcome the limitations associated with conventional pavement moduli backcalculation, data mining tools such as support vector machines, neural networks, decision trees, and meta-algorithms like bagging were used to conduct asphalt pavement inverse analysis. The resul...

Investigating traffic accidents: the interaction between a motor vehicle and a pedestrian

Abstract: The paper presents the methodology for expert investigation of traffic accidents involving running over pedestrians. This methodology is aimed at determining the availability of any technical possibility for a motor vehicle driver, driving at a particular speed, to avoid hitting the pedestrian in a particular situation. Furthermore, the paper presents the analysis of different investigation methods and the description of investigation procedures. Various patterns of the path of the motor vehicle and the pedestrian travel before the accident are described, providing a deeper insight into the peculiarities of investigation of each particular pattern. The description is supported by the case study, illustrating the investigation of a specific traffic accident, involving actual hitting of a pedestrian. The methodology presented may be successfully used for investigating traffic accidents by experts.

An aggregate transport demand model for import and export flow simulation

Abstract: This paper presents a system of models for the estimation of international (import/export) freight flows through a partial share approach. It allows us to simulate attraction, production, distribution and modal split for the estimation of modal Origin-Destination matrices in quantities. Aiming at predicting long term effects for strategic planning, the modelling system has been specified through easy-to-capture variables represented by level-of-service attributes and aggregate socio-economic variables. The calibration was carried out by using a set of available data in Italy that allowed us to consider import/export flows for different freight types given by the aggregation of classes provided by European NST/R classifications.

Performance assessment of a private finance initiative road project

Abstract: Private Finance Initiative (PFI) projects are designed to fund long-term infrastructure projects and public services. A typical PFI road scheme involves the public sector client (Granting Authority), the private sector partner – Special Purpose Vehicle (SPV), the financial lenders, the road constructor and its supply chain, technical advisers (legal, financial, technical) and the operation and maintenance (OM in accordance with all statutory requirements and Environmental Statements; in accordance with the road project's Quality Plan; and in accordance with Good Industry Practice in order to satisfy the Granting Authority Requirements. The concession period of the study project is 30 years. It is the most important phase because during this time both the service details and payment is created. The payment of the unitary fee is conditional ...

Fatigue and brittle fracture of carbon steel of gas and oil pipelines

Abstract: The areas of low frequency and corrosion fatigue for basic metal and welding joints of oil and gas pipelines have been determined on the basis of corrosion-fatigue test results. The most dangerous diapasons of the operation loadings were also determined. The present work also proposes the methodical approaches to the survivability prediction.

Examination of staggered shifts impacts on travel behavior: a case study of Beijing, China

Abstract: Staggered shifts is one of the popular TDM (Transportation Demand Management) policies, which can reduce commute travel volume during the AM and PM peak periods, and relieve traffic congestion. In order to make effective staggered shifts program, it is necessary to examine the effect of the program on commute travel behavior. This paper takes Beijing (China) as an example to evaluate the validity of staggered shifts policy. Based on data investigation, the commute travel behavior and the commuters’ preference for staggered shifts are analyzed. This paper makes four staggered shifts programs, and develops a commute departure time choice model with Multinomial Logit method to predict the influence of the programs on commute departure time, and develops a commute travel duration model to analyze the influence of the programs on commute travel time. Departure time prediction shows that Program B can reduce the traffic volumes in 6:30–8:30 period by 15.24%, and commute travel duration analysis indicat...

An analysis on the connections of factors in a public transport system by AHP-ISM

Abstract: In order to gain an overall view on all relevant connections of the elements in a public transportation system, a systematic approach is advisable to follow, which applies well-proven methodology. In case a structure contains both hierarchical and non-hierarchical connections, the formerly recommended methodologies are: ISM-AHP, ISM-ANP, ANP. This paper however proposes a different approach: AHP-ISM, which aims to keep the AHP hierarchy, but simul- taneously to amend that with the non-hierarchical types of linkages within the structure. By that, those connections that were verified in the AHP procedure can be considered dominant, but also weaker linkages might provide impor- tant additional information about the whole structure. The additional ISM procedure is suitable for two purposes: the most influential elements of the AHP structure can be selected, moreover also direct and indirect impacts of element improvement might be followed in the structure by considering both types of connections withi...

The analysis of traffic accidents on Lithuanian regional gravel roads

Abstract: A great number of serious road accidents occur all over the world every year. In spite of some progress in this area, road traffic safety has remained an acute problem in recent years. Traffic accidents on the road depend on the following factors: road traffic volume, road traffic speed, road condition, weather conditions for traffic, driving experience and driving culture. All these factors are related to traffic safety, human lives and health. The main goal of this work is to provide a statistical analysis of traffic accidents and investigate the causes, structure, dynamics and seasonal character of traffic accidents on Lithuanian regional gravel roads. It has been established that seasons play an important role for traffic accidents on regional gravel roads in Lithuania. Rates for traffic accidents increase from spring to autumn. The number of traffic accidents on Lithuanian roads decreased considerably in 2008 and 2009.

What variables affect to a greater extent the driver's vision while driving?

Abstract: This paper deals with the analysis of the main variables involved in the visual activity of a driver of motor vehicles, in order to identify the most important quantities and implement, therefore, appropriate corrective actions to the achievement of road safety. The first step in this research was to survey a number of variables within the road environment and processing this data base with clustering techniques in order to extract useful information for purpose. In this case, a mixture of procedures based on Fuzzy Logic (FL) and Artificial Neural Network (ANN) were applied not only to extract knowledge not known a priori but, above all, to define the membership functions and rules of the fuzzy model without recourse to the skills of the analyst, not always so objective. This procedure, applied to a rural road open to traffic, showed a good performance in predicting the user's visual behavior and, especially, in identifying the most influential variables. This aspect may allow the agency to direct...

The exploitation and environmental characteristics of diesel fuel containing rapeseed butyl esters

Abstract: In an effort to consume fewer non-renewable resources and use primarily raw materials of biological origin in the production of biofuel, biomass-derived biobutanol can be used for transesterification of rapeseed oil. The study investigates the physical and chemical characteristics of rapeseed oil butyl esters (RBE) and 10%, 20% and 30% RBE-diesel composites. Characteristics of RBE and their composites with conventional diesel (D) are a little different from rapeseed oil methyl esters (RME) and their composites with D, while their basic characteristics comply with the requirements of European Standard EN 14214. Comparative tests in 4-stroke 4-cylinder 1Z type diesel engine of Audi-80 using 10-30% RBE and 10-30% RME compounds as fuels have been performed, and the results indicate that the biologically derived additives improved the energy characteristics of the engine but increased the fuel consumption compared to pure diesel. Increasing the bio-component concentration up to 30% in diesel and biodiesel fuel (RME and RBE) mixtures leads to complex improvements in the environmental impact compared to pure diesel; however, in the case of mixtures with RBE, slightly higher concentrations of carbon dioxide (CO2), hydrocarbons (HC) and nitrogen oxides (NOx) were observed in engine exhaust gases compared to RME and D mixtures of analogical composition.

Multiple criteria assessment of a new tram line development scenario in Vilnius City public transport system

Abstract: This paper considers the technological development of an additional network for Vilnius City public transport. Several types of scenarios for the development of Vilnius City tram line were analysed. This paper describes the situation pertaining to Vilnius City transport system as well as the traffic parameters, which are used for a multiple attribute ranking of a tram line development in Vilnius City. The multiple attribute criteria methods have been chosen to perform the ranking of three development scenarios and to estimate the best alternative based on the traffic conditions of Vilnius City. The experts of different decision-making groups have performed the importance analysis of traffic parameters, which were chosen for the assessment of alternative scenarios for the tram line development. The transport system experts were used to determine the relative weights of indicators. Two methods – TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and SAW (Simple Additive Weighting) – wer...

Effects of altitude on the soot emission and fuel consumption of a light-duty diesel engine

Abstract: A four-cylinder, direct-injection (DI) diesel engine was used to study the effects of altitude on the variations of the exhaust soot emission and engine performance. The experiments were conducted in Mashhad, Iran, at an altitude of 975 m above sea level. A three-lobe rotary blower of Roots type was employed in order to simulate the altitudes down to 350 m by increasing the inlet manifold pressure of the engine. The tests were performed based on the ECE-R49 test cycle, and for each testing point, the experiments were repeated for five boosting pressures which correspond to five different altitudes. Results indicate that with increasing the altitude from 350 m to 975 m, the soot emission increases about 40%. This increase is due to the relatively lower the air density introduced into the cylinders in higher altitudes that leads to the increase of autoignition delay time which could shorten the late combustion phase; hence, the soot burnout process deteriorates. Also it was found that at low engine loads, the Brake-Specific Fuel Consumption (BSFC) increases about 20% with raising the altitude from 350 m to 975 m. At higher loads, the raising rate of fuel consumption is insignificant. The effects of altitude on the other engine parameters such as induced air mass flow rate, volumetric efficiency, equivalence ratio, and exhaust temperature were investigated as well. In addition, a sensitivity analysis was conducted and the results revealed that among the engine parameters, the soot emission alteration has the most sensitivity to the change of the altitude.

Methods for numerical calculation of parameters pertaining to the microscopic following-the-leader model of traffic flow: using the fast spline transformation

Abstract: As known in transport engineering, civil engineering, transport planning and mathematics, traffic flow is the study of interactions between vehicles, drivers and infrastructure (including highways, signage and traffic control devices), with the aim of understanding and developing an optimal road network with efficient movement of traffic and minimal traffic congestion problems. The presented paper discusses a small part of a traffic flow study – the development of the methodology for assessing the speed and acceleration of a car during the column movement followingthe-leader, based on a new mathematical method. Two methods – (1) the numerical calculation of the first derivative, i.e. speed of the car movement; (2) the numerical calculation of the second derivative, i.e. acceleration of the car movement – were developed, using the fast spline transformation. In the future, parameters obtained with the help of two new methods, can be used to solve complex transportation problems, such as: (1) control of tra...

A methodology for modelling traffic related emissions in suburban areas

Abstract: A methodology that integrates a computer program COPERT III for calculation of traffic emissions estimates, and a transportation modelling software CUBE VOYAGER was used to assess pollutant emissions for a suburban area, as a support for future transport planning strategies to be applied for any developing road network. COPERT III is used to obtain the carbon monoxide emission factors by accounting for the car fleet composition, characteristics and average speed. An aggregated emission parametric equation was determined and used further on for estimating network carbon monoxide emissions based upon the output of macroscopic traffic characteristics enabled by traffic simulation software, CUBE VOYAGER. The methodology and modelling results are applied here for Floresti, a satellite town of Cluj-Napoca, Romania.

The mechanism of drive system flexible suspension and its application in locomotives

Abstract: The drive system flexibly suspended on the bogie frame is conducive to the lateral dynamic performances of locomotive. In order to clarify the mechanism and optimize the suspension parameters using this model, a bogie dynamics model with 10 degrees of freedom (including the drive system) was established. The lateral dynamic performances were analyzed with the different suspension parameters. The mechanism was determined from the dynamic vibration absorber and the best suspension frequency of the drive system was put forward. The multi-body-dynamics model with two types of drive systems was simulated in locomotives to verify this theoretical analysis. When the suspension frequency is close to the hunting motion frequency of the wheelset, the locomotive dynamics performed the best. The length of the swing rods at the front and rear drive systems were different on the same bogie, which improved the locomotive dynamic performances within a wider range of speed and the wheel conicity. The track shift f...

Calibrating the passenger car equivalent on Italian two line highways: a case study

Abstract: The Level of Service (LOS) of a road infrastructure, a concept introduced for the first time in the Highway Capacity Manual (second edition), is defined as the ‘qualitative measure of traffic conditions and their perception by users’. The Highway Capacity Manual, developed in the U.S., is still the most highly internationally credited reference text in the study of vehicular traffic. The method proposed by the Highway Capacity Manual is based mainly on studies and research compiled in the U.S., so in order to apply this method to other realities (e.g. Italy), research needs to be carried out at a local level. In this study, a series of studies were carried out to verify the transferability of these procedures to two roads classified as ‘two-lane highways’. Two fixed RTMS (Remote Traffic Microwave Sensor) were used to record traffic data for two sections located at 3100 km on the SP30 and at 8900 km on the SP175 from 1 January to 31 December 2010. From the data, it was possible to determine not onl...

Lithuanian road safety solutions based on intelligent transport systems

Abstract: The rapid growth of traffic intensity was predetermined by the dynamic change in the number of cars and the need for carriage. Vehicle congestion and high risk of accidents result in disappointment of many drivers and public transport users, causing psychological tension and increasing the accident rate. The accident rate is one of key indicators that help measuring processes of the transport system and its development. With the help of various road safety solutions, the modern world aims to ensure safe transportation and achieve reduction in the number of traffic accidents. Just as any other country, Lithuania is focusing on these issues as well. Reduction in the number of traffic accidents requires implementation of the national road traffic safety policy, which is one of the most important instruments that specify directions to be taken while implementing road safety solutions for roads with the highest traffic accident rate. The paper presents a methodology for calculating traffic intensity, ...

Seaport positioning supported by the combination of some quantitative and qualitative approaches

Abstract: The ports' management is facing the challenge of sustainable port development, considering several aspects: economic, technological, logistical, environmental, and community involvement. Although the numerous scientific concepts have been developed for explaining the trends of ports' involvement into the logistics chains, this research work presents an attempt to draw the attention to the marketing aspect of the port mission, being focused primarily on the customers' needs, whose preferences are the key factor in selecting specific port in competitive environment. Therefore, the Adriatic, Aegean, and Black Sea ports, sharing the unique marketing features and target market, have been analyzed with the aim to be mutually positioned. The considered ports have similar goals: to achieve the greater degree of competitiveness as well as to acquire the larger number of customers being attracted on the basis of superior port choice criteria. These circumstances have been explored through some distinctive quantitative and qualitative criteria by employing the appropriate, well known and structured quantitative PROMETHEE and AHP method. The obtained results are presented by perception maps, and described on the basis of gained quantitative indicators and the qualitative explanations given by the authors, primarily, in the marketing manner.

Affective-sound effects on driving behaviour

Abstract: Recent technological developments in active advanced driver assistance systems and in-car infotainment devices have contributed to reducing the number and severity of road accidents as well as improving and simplifying driver experience. However, these systems may impact driving performance in undesired ways, especially when emotionally-charged stimuli are used as warning signals. Emotional distraction can be a serious danger, causing delays in information processing, and reducing driving safety below minimal acceptable levels. Here we study the effect of emotionally-laden auditory signals on the speed of concurrent driving decisions. We distinguished two categories of behavioural responses: ‘urgent’ vs ‘evaluative’. In the experiments reported here participants were quicker to evaluate whether a traffic scene was risky or not after hearing an emotionally-charged auditory stimulus than after a neutral one. However, urgent (braking) responses to the same scenes were not affected by the emotional qu...

New method for benchmarking traffic safety level for the territory

Abstract: Evaluation, monitoring and comparison of traffic safety in various territories presents a major challenge to the traffic safety researches. Recently a large number of studies are focused on finding an appropriate method for the calculation of the traffic safety level which uses a single numerical value for its assessment. For that purpose, traffic safety indicators are combined into a single numerical value by appropriate techniques in order to represent a grade of the traffic safety level. This paper contains, after the summary of contemporary tendencies in the evaluation of traffic safety levels, the analysis of methods used in the evaluation of traffic safety levels so far in Serbia with the emphasis on their values and deficiencies. Considering those analyses, this paper introduces a new method for traffic safety level evaluation the so called Benchmarked Traffic Safety Level (BTSL). BTSL implies selection of appropriate indicators, transformation of chosen indicators, assigning weights and aggregation. The proposed scale appliance enables traffic safety level to define for the territory, and also compares it with a similar one. BTSL provides a single numerical value so that to evaluate the traffic safety level for the territory, derived from the aggregation of previously transformed and 'weighted' three outcomes indicators and three safety performance indicators.

Research of the influence of tire hydroplaning on directional stability of vehicle

Abstract: Vehicle use is inherently linked to the risks. While transport means are being constantly improved, active and passive safety issues appeared to be more and more complex what makes experimental testing and numerical modelling problems of safety – sensitive structures considerably actual. In case of hydroplaning phenomenon to keep the vehicle's stable direction its movement becomes more difficult. Selection of the safe speed is one of the main objectives in order to ensure greater traffic safety and reduce the possibility of an accident. The aspects of tire simulation by finite element method were revealed and analysis of the impact of a vehicle's speed on the appearance of hydroplaning process was performed. The peculiarities of Euler–Lagrange formulation of dynamical problems and modelling of fluid – structure interaction by finite element method are presented in the research. The article describes preliminary models developed using the PATRAN and DYTRAN software packages. On the basis of these m...

Solving the nonlinear discrete transportation problem by MINLP optimization

Abstract: The Nonlinear Discrete Transportation Problem (NDTP) belongs to the class of the optimization problems that are generally difficult to solve The selection of a suitable optimization method by which a specific NDTP can be appropriately solved is frequently a critical issue in obtaining valuable results The aim of this paper is to present the suitability of five different Mixed-Integer Nonlinear Programming (MINLP) methods, specifically for the exact optimum solution of the NDTP The evaluated MINLP methods include the extended cutting plane method, the branch and reduce method, the augmented penalty/outer-approximation/equality-relaxation method, the branch and cut method, and the simple branch and bound method The MINLP methods were tested on a set of NDTPs from the literature The gained solutions were compared and a correlative evaluation of the considered MINLP methods is shown to demonstrate their suitability for solving the NDTPs

Application of the MODIPROM method to the final solution of logistics centre location

Abstract: Awareness of the role of logistics centres is the precondition for successful planning, optimization, design, management, control and analysis of logistics processes and subsystems. Transportation requirements in supply chains, ecological requirements and the need for quality life in cities particularly emphasize the importance of selection of logistics centre locations, manner and time of supply. Taking into account the significance of selection and ranking of different locations, it is necessary to compare, as objectively as possible, the influences of various criteria and reduce them to a common function, i.e. present the methodology of solving complex problems associated with ranking of alternatives. The proposed method is expected to be a comprehensive tool of decision makers during the selection of the optimal logistics centre locations.

An inverse dynamics method for railway vehicle systems

Abstract: The wheel–rail action will obviously be increased during the vehicles in high-speed operation state. However, in many practical cases, direct measurement of the wheel–rail contact forces cannot be performed with traditional procedures and transducers. An inverse mathematical dynamic model for the estimation of wheel–rail contact forces from measured accelerations was developed. The inverse model is a non-iteration recurrence method to identify the time history of input excitation based on the dynamic programming equation. Furthermore, the method overcomes the weakness of large fluctuations which exist in current inverse techniques. Based on the inverse dynamic model, a high-speed vehicle multibody model with twenty-seven Degree of Freedoms (DOFs) is established. With the measured responses as input, the inverse vehicle model can not only identify the responses in other parts of vehicle, but also identify the vertical and lateral wheel–rail forces respectively. Results from the inverse model were c...

Power circulation in driveline system when the wheels of tractor and trailer are driven

Abstract: In off-road “tractor–trailer” vehicle combinations, the trailer can be equipped with one or more driving wheels. The distinguishing feature of vehicles with two or more driving axles is distribution of total power between the driving wheels. In machines with several driving axles, kinematic mismatch between theoretical wheel speeds nearly always takes place. The wheels of tractor and trailer can slip uniformly and differently, some of them may even slide. It is unfortunate when the wheels slide, as power circulation takes place. In this paper, power circulation of a vehicle composed of a tractor and trailer having driving wheels and driving wheels’ interaction with soil is investigated. The conclusion is that in a vehicle composed of two machines having two driven axles each, circulation of power can be avoided or reduced by turning off one driving axle in the machine, which delivers more power and has advancing driving wheels.