Multiple Criteria Evaluation and the Inverse Hierarchy Model for Justifying the Choice of Rail Transport Mode

The choice of a particular mode of transport as an alternative to another one is subjective and usually based on an individual passenger’s approach to the evaluation of advantages and disadvantages of some particular means of transport. The paper presents the methods of analysing the reasons for passengers’ choice of travelling by train as an alternative to using air transport and the results obtained in the research. The 16 criteria (sub-criteria), describing the advantages of travelling by rail over air travel, are defined. The data of the survey questionnaire filled by 52 passengers of the Vilnius–Moscow train and the ranks assigned by them to the considered criteria are described. The average ranks of all 16 criteria and their normalized subjective weights are calculated by using a new method of average rank transformation into weight (ARTIW). The average ranks assigned by the passengers of the train to sub-criteria and the calculated global weights show what criteria are most important. Using the inverse hierarchy model based on the sub-criteria weights, the most and the least important groups of criteria are determined. The institutions and companies engaged in passenger transportation by rail, which give priority to improving the services described by the most important criteria, can make this mode of transport more attractive to people.</p

Variability of gravel pavement roughness: an analysis of the impact on vehicle dynamic response and driving comfort

Gravel pavement has lower construction costs but poorer performance than asphalt surfaces on roads. It also emits dust and deforms under the impact of vehicle loads and ambient air factors; the resulting ripples and ruts constantly deepen, and therefore increase vehicle vibrations and fuel consumption, and reduce safe driving speed and comfort. In this study, existing pavement quality evaluation indexes are analysed, and a methodology for adapting them for roads with gravel pavement is proposed. We report the measured wave depth and length of gravel pavement profile using the straightedge method on a 160 m long road section at three stages of road utilization. The measured pavement elevation was processed according to ISO 8608, and the frequency response of a vehicle was investigated using simulations in MATLAB/Simulink. The international roughness index (IRI) analysis showed that a speed of 30-45 km/h instead of 80 km/h provided the objective results of the IRI calculation on the flexible pavement due to the decreasing velocity of a vehicle’s unsprung mass on a more deteriorated road pavement state. The influence of the corrugation phenomenon of gravel pavement was explored, identifying specific driving safety and comfort cases. Finally, an increase in the dynamic load coefficient (DLC) at a low speed of 30 km/h on the most deteriorated pavement and a high speed of 90 km/h on the middle-quality pavement demonstrated the demand for timely gravel pavement maintenance and the complicated prediction of a safe driving speed for drivers. The main relevant objectives of this study are the adaptation of a road roughness indicator to gravel pavement, including the evaluation of vehicle dynamic responses at different speeds and pavement deterioration states

Research and evaluation of ruts in the asphalt pavement on Lithuanian highways

When exposed to destructive climate and weather factors and heavy vehicle loads, the pavement wears and deflects. In recent decades, apart from cracks and potholes, the depth of ruts grows and makes an increasing share of the pavement surface. The deeper are the tracks, the poorer are traffic conditions for fast-moving cars: drivers are struggling, speed is decreasing and the number of accidents is increasing. After track depth reaches a critical and permissible limit, the road surface must be repaired or speed limit has to be reduced. The work presents a theoretical analysis of track emergence causes and factors determining their depth. With the help of Mobile Road Research Laboratory RST 28, the track depth of all Lithuanian highways has been measured every 20 metres. The obtained data have been processed using the methods of mathematical statistics. Each road has a sample average of every rut, sample standard deviation and a coefficient of individually measured variation. The paper has drawn histograms, calculated skewness, kurtosis and normal distribution and provided lognormal distribution curves of a probability density function. The visualisation and empirical skewness and kurtosis values have revealed that the depth of the rut distributes according to lognormal rather than normal distribution. The average values of the roads having a dividing strip and standard deviations from the distribution across the road have been received. The given dependence of the rut depth of a standard deviation on the averages of rut depth shows an elastic interface of these parameters (determination coefficient R2= 0.741)

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

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 filling in the questionnaire based on the Analytic Hierarchy Process (AHP) and the sequence of calculations of the consistency of expert estimates in the process of determining the weights of the investigated interactions. The Kendall's coefficient of concordance has been used for calculating the weights assigned to the criteria by a group of experts and estimating the consistency of the ranks based on them. Finally, the paper presents a new method for evaluating expert judgements with reference to the use of the correlation analysis of ranks and weights. The significance of the calculated pairwise correlation coefficients has been validated by the Student's t-test and lowest value thus allowing us to consider that the expert opinions about the impact of the interaction of TS elements on the traffic accident rate are consistent

Conditional optimization mathematical model of the asphalt concrete mixture grading

A new partial conditional optimization method which enables to select the best ratio of imported fillers not only while designing the composition of asphalt concrete mixture but also while adjusting the composition of the produced asphalt concrete mixture according to the actual quality of hot fractions is presented. The constructed mathematical model, algorithm and the solved task prove that irrespective of the number of fillers (from 2 to 7 and more) the ratio of their mass can be selected which enables to produce an asphalt concrete mixture which meets the requirements of the composition project best. The mass ratio λ of imported fillers A 1 and reclaimed dust A 2, which settled and accumulated in the dry purification equipment of an asphalt concrete plant presented in Regulations DAT.AD-96 was taken into account for the first time. Methodological scientific novelty and a possibility to apply it in practice can improve the control of asphalt concrete mixture production. Frist Published Online: 30 Jul 201

Expert evaluation of criteria describing the quality of travelling by international passenger train: technological, economic and safety perspectives

The goals, needs and possibilities of interested parties (administration, service staff and passengers travelling in a train) should be taken into account when organizing passenger transportation and making decisions concerning particularly this area. Improvement in passenger transportation (train travel) depends on experience, qualification and decisions made by the experts involved in this process. The paper analyses the performance of the joint-stock company Lietuvos geležinkeliai and examines criteria describing the quality of passenger transportation provided by this organization. The article presents the methods for showing the consistency of respondent and expert judgements on ranking the sets of criteria defining the quality of travelling by train. The significance of the considered criteria is based on a pair wise comparison. The employed method allows for determining the normalized weights of particular criteria with respect to other criteria of the analysed group (A, B, C, D). The article offers an algorithm for displaying the quality of train travel. The ranks assigned to the criteria by train passengers (category K), service staff (category P) and administrative staff (category A) are calculated establishing the differences between the ranks of criteria. The opinions of the respondents and experts belonging to categories K, P and A are compared considering the significance of the adopted criteria. The paper provides the results obtained from the surveyed respondents and experts and presents the ranks given to criterion groups A, B, C, D describing the quality of train travel. Finally, the conclusions based on the performed research are presented

Manufacturing technologies and dynamics of hot‐mix asphalt mixture production

In most countries, the pavement of motor roads, airfields and other trafficked areas is made of hot‐mix asphalt (HMA) mixture prepared by asphalt mixing plants (AMP) of various designs. The total output of HMA mixtures shows the dynamics of national road transport infrastructure's development, corresponding to the increasing number of vehicles, traffic intensity and axle loading. HMA mixtures are made by using various technologies, which have some advantages and disadvantages. The paper presents technological schemes of making HMA mixtures used in Lithuania and other countries. The development of AMP and technical and technological characteristics of new computer‐aided AMP models used at various asphalt production companies (APC) were analysed. Based on the data provided by the European Asphalt Pavement Association (EAPA), the correlational‐regression relation between the country's area and the amount of the produced HMA mixtures was established. The data on the total output of HMA mixtures in Lithuania cannot be found in the information provided by EAPA. For the first time, the dynamics of the production of HMA mixtures by particular APC in Lithuania over the last 10 years (1998–2007) has been determined based on the data directly obtained from their manufacturers. The data were analysed and compared to the output of HMA mixtures in other countries and the dynamics of the development of AMP models used in Lithuania and changes in their numbers were determined. Santrauka Daugelyje šalių automobilių kelių, skridimo aikštelių ir kitų eismo zonų danga įrengiama iš karšto maišymo asfalto (KMA) mišinio, pagaminto skirtingos konstrukcijos asfaltbetonio maišytuvuose (ABM). KMA mišinio gamybos apimtys rodo šalies kelių transporto infrastruktūros plėtros dinamiką ir atitiktį didėjantį automobilių skaičių, jų eismo intensyvumą ir ašies apkrovas. KMA mišinys gaminamas taikant skirtingas technologijas, turinčias privalumų ir trūkumų. Darbe pateiktos Lietuvos Respublikos ir kitų šalių KMA mišinių gamybos technologijos schemos. Išanalizuota ABM tobulinimo raida ir įmonėse veikiančių naujų modelių kompiuteriais valdomų ABM techninės ir technologinės charakteristikos. Naudojant European Asphalt Pavement Association (EAPA) duomenis, gauta koreliacinė-regresinė šalies ploto ir pagaminto KMA mišinio kiekio sietis. EAPA skelbiamoje informacijoje nėra duomenų, rodančių suminius Lietuvoje pagaminto KMA mišinių kiekius. Pirmą kartą iš asfalto mišinių gamintojų surinkus ir susisteminus duomenis, tiesiogiai gauta 10 metų (1998–2007) Lietuvos Respublikos asfaltbetonio gamyklose (ABG) pagaminto KMA mišinių kiekio dinamika ir ji palyginta su kitose šalyse pagaminto KMA mišinio kiekiais. Atlikta Lietuvoje veikiančių ABM modelių ir skaičiaus kaitos dinamika. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: karštai maišytas asfaltas, asfaltbetonio maišytuvas, asfaltbetonio gamykla, periodinio veikimo maišytuvas, produkcijos dinamika, technologiniai procesai

The criteria for identifying the quality of passengers’ transportation by railway and their ranking using AHP method

Passengers’ transportation by rail involving various interested groups, such as managers, service staff and passengers, is a complicated process. Decision‐making persons, organizing railway trips should take into account the interests, needs and possibilities of these particular groups. The solution to some problems associated with passengers’ transportation by rail depends on the experience and qualification of decision‐makers, people who are responsible for the effectiveness of this work. To increase the quality of railway trips, the interested parties, groups of people mentioned above, should coordinate their actions, cooperate with each other in solving the problems and exchange relevant information. Therefore, the increasing quality of passenger transportation is a complicated issue, requiring good professional skills based on knowledge, practical experience, high intellect and new ideas of all the people involved in this process. The current paper presents a diagram showing passenger's transportation quality with a number of criterion groups A, B, C, D matching the structure and numbers of the questions included in the questionnaires to survey respondents (passengers) and experts (service and administration staff of the train). What is more, the Analytic Hierarchy Process (AHP) methodology based on the pair wise comparison of criteria is used to determine their weights (significances) considering the data obtained from the respondents and experts of each of three categories. Only these questionnaires which have no contradictory estimates are used. Also, the calculation methods demonstrating the results of the survey are provided in this work. One more point such as the data elicited from the respondents who took part in the survey (i.e. passengers from the train running on the international route Vilnius‐Moscow) and experts (i.e. service staff of the already mentioned train and representatives of the administration staff from the Joint‐Stock Company ‘Lithuanian Railways’ (AB ,,Lietuvos geležinkeliai")) is analyzed. Finally, the conclusions for improving the quality for passenger transportation by Lithuanian railways are given. First published online: 10 Feb 201

Regularities of defect development in the asphalt concrete road pavements

A new classification of asphalt concerete pavement defects is presented in the article and the causes of their development are systematised. The dynamics of asphalt concrete pavement defect development in the road and the dependence of pavement deterioration on the type of defects are presented in the theoretical graphic model. The change of road pavement structural strength (stiffness modulus) depending on the pavement service life is also described. The dependence of the level of asphalt concrete pavement on the most important roads of the Republic of Lithuania (road Vilnius-Kaunas [Al] and motorway Vilnius Panevėžys [A2]) measured with one-wheel dynamometric trailer PKRS-2U (Russia) on the level of pavement deterioration has been identified through experiments. The analysis of the dependence of transport costs and driving speed on road pavement level has been carried out. Regression equations of such dependence and correlation coefficients as well as relations are presented too. Frist Published Online: 30 Jul 201

The bitumen batching system's modernization and its effective analysis at the asphalt mixing plant

Some particular aspects such as the improvement methods of technological parameters for hot bitu‐ men storage in a pipeline transport system, transportation and dosed supply to batch asphalt mixing plant (AMP) are evaluated in this paper. Bitumen in asphalt concrete binds together the material of mineral particles into a strong conglomerate of a complicated structure, capable of withstanding the destructive effect of vehicles and the factors on the road pavements. The optimal amount of bitumen determined by calculation and laboratory testing should be maintained in mix batches of hot‐mix asphalt (HMA) obtained from AMP mixer. In the periodic type of the asphalt concrete blender mass of the weighted matrix in the all merging batcher's tanks should correspond in percents equally in the HMA to the designed amount of the job‐mix formula (JMF). The bitumen batcher does not always weigh bitumen portions precisely. Their mass deviations from the amount determined by JMF and its variation impair HMA composition and performance. In addition,, an additive model for calculating the effect of factors causing the variance of bitumen content in the produced HMA mixture is presented in this current paper as well. The data on statistical evaluation of bitumen batcher's modernization performed at certain Lithuanian Enterprise are discussed. The differences in structures of reconstructed and not reconstructed bitumen batching systems (BBS) are analysed and methods of determining modernization effectiveness are presented. The effectiveness of BBS is analysed too, defining the deviations of bitumen content in subsamples, taken and extracted everyday for two seasons (before and after the batcher's modernization) of HMA mixture production from the value of JMF and comparing them to the values of tolerances. The analysis of column charts and histograms shows that the made modernization helped to increase the precision of supplying the required amount of bitumen to HMA mixture insignificantly. However, the control of BBS has been considerably increased. First published online: 10 Feb 201