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Cyclists are a vulnerable group of road users, especially when no separate infrastructure for cyclists is provided. Then,road factors such as distance and altitude differences can indirectly affect cyclists' safety. Therefore, the authors proposed a procedure based on the geometric characteristics of the road that can determine riding difficulties for cyclists. The proposed procedure can be used both by the public authorities whomanage cyclists' safety and as a method of classifying the road network for cycling. The proposed procedure, based on the use of pattern recognition techniques, analysesdata from a sample of nine riders who travelled on rural roads within the Municipality of Messina (Italy) to classify the roads according to their cycling difficulty. For each rider, duration, distance, road slope, altitude difference and spent calories have been measured and analysed.The collected data wereused for the development of a model capable of predicting the cyclist’s physical effort as a function of the road alignment itself. Knowing the effort required to cycle along a route can contribute to a more complete assessment of road classification, commonly defined according to motor vehicles. Moreover, it may constitute a measure determining the safety of cycling by encouraging cyclists to travel along roads compatible with their physical abilities.

Functionality of a square used for ferry boats boarding has repercussions on safety and comfort of users, as well as on the efficiency of maritime transport. Inadequate use of the infrastructure causes driving errors followed by corrective manoeuvres, loss of time and potential accidents with consequences for community and the maritime transport compa-ny. The wide diversification of traffic components and payment methods are generally managed through a traditional horizontal and vertical signage system that does not refer to any current legislation. Therefore, the purpose of this research is to investigate driver's behaviour and the interaction that takes place between the latter and the environ-mental context. In particular, the authors focused on the study of the driver’s workload in a simulated environment, considering a users' sample and different driving scenarios inside the boarding area, concerning traffic conditions (isolated vehicle or presence of disturbing vehicles) and signs position. All this, in order to evaluate whether any change in a virtual context could bring real benefits to drivers, before being transferred to the real context. The results obtained, in terms of subjective workload and performance measures, have made it possible to judge the different solutions proposed in a simulated environment through synthetic indices referring to the entire boarding place or at certain parts of it. In this way, the manager can decide to change the circulation of the entire square or only some aspects of detail, such as some signals, in the event that they manifest an evident difficulty in the transfer of infor-mation. The use of the simulated environment allows greater speed in identifying the best solution, lower costs (avoid-ing the creation of a critical configuration for circulation) and greater user safety, since risky manoeuvres are identi-fied and corrected by the simulator. The proposed procedure can be used by managers for a correct arrangement of the signs, for the purpose of correctly directing the flows and maximizing the flow rate disposed of.

The role of road markings is fundamental for traffic safety, as it represents an essential optical driving instrument both for effective drivers and autonomous vehicles. This research aims to evaluate the effects of the decay of road marking visibility along curves, specifically the variability in lateral acceleration. Traditionally, issues related to the correct interpretation of a road alignment were studied by means of trajectory analyses. However, they involved information about the vehicle’s geometrical position without any indication on dynamics. To explore this aspect further, an experiment in a simulated environment involving 21 drivers was performed. They drove along a test road in a standardized scenario considering only three variables: the curve direction (right or left), the deviation angle (70° or 30°), and the road marking visibility percentage (100%, 50%, 10%, and 0%). The results, in differences between theoretical (depending on design speed and curve radius) and effective lateral accelerations, provide further evidence of the strategic role of the markings. However, when markings deteriorate, drivers activate some balancing mechanisms to mitigate the dynamic effects along curves and, in turn, to improve comfort and safety. The proposed procedure is not only of direct practical interest, but it is also fully generalizable to other contexts and issues, involving several other elements that may influence the phenomenon, such as road geometry, visibility conditions, and traffic flow speed.

The possibility of using some warnings inside modern vehicles should be an aid to the driving activity. However, the information transferred to users is not always received in the expected way due to the variability and complexity of the road environment. This study, therefore, aims to identify a procedure that allows to ascertain whether drivers receive the data in an appropriate way even during particular manoeuvres, such as passing cyclists on a winding road or, on the contrary, if they represent an unnecessary overload. To answer this question, an experimentation in a simulated environment was set up with which the drivers’ visual behaviour was recorded in presence and absence of a driving aid device (On- Board Unit, OBU). The results show that, in some situation, the information provided by the OBU helps to maintain a more virtuous driving behaviour but, in the most complex ones, drivers acquire information from a smaller number of sources, excluding the aid devices present inside the cockpit. This procedure is useful for ADAS designers in order to refine these instruments but also for road managers who can improve safety by inserting appropriate signs or speed limits.

Traffic loads and environmental factors cause various forms of distress on road pavements (cracks, depressions, potholes, ruts, etc.). Depressions and ruts produce localized variations of longitudinal and cross slopes, which are very hazardous for drivers, especially during rain. In such conditions, these defects alter the surface water path, creating abnormal water accumulations and significant water film depths to induce aquaplaning risk. In current practice, in preliminary analysis phases and at the network scale, the control of road surfaces is carried out with expeditious techniques and with synthetic indicators, e.g., pavement condition index (PCI), through which a quality judgment related to the detected distresses on the pavement surface, is given. In truth, the detection of specific defects (ruts and depressions) should also include further analyses to evaluate the hydraulic efficiency of the carriageway related to their severity. Therefore, in this paper, a synthetic indicator called Hydraulic Condition Index (HCI) is proposed for evaluating the hydraulic quality of road pavement surfaces. This index is related to the hydrologic conditions of the site, the pavement characteristics, and the defects that can alter the flow of water on the carriageway, determining and increasing the risk of aquaplaning. The methodological framework is discussed by means of some numerical applications developed for different road typologies according to their functional classification. The final aim is to provide road agencies with another solution to evaluate road quality and ensure safer roads for users. The methodological framework for evaluating the HCI may be adopted by the road agencies for the network-scale priority ranking of road segments maintenance needs also involving safety traffic conditions.

In recent years, the growing survey capability for continuous and frequent inspections of road pavement conditions has raised questions regarding the optimal solutions for data management. Consider...

To accurately schedule maintenance operations, it is crucial to monitor the pavement state and, thus, evaluate the structural and functional indices during its entire service life. In particular, surface conditions (cracks, potholes, patches, rutting, etc.) must be properly checked – especially in terms of detection, identification, and classification of distresses – for avoiding reaching dangerous values for users (overpassing safety thresholds). However, monitoring and survey activities can be so costly (not only in economic terms, but further considering the execution time) to discourage their execution, with evident drawbacks for a proper maintenance management and the related intervention strategies. In view of the above, a novel device for real-time and continuous survey of road pavement surface distresses was developed in the Infrastructure Lab of the University of Messina. Using the potential of laser lighting systems and 3D cameras for optical triangulation, this device can acquire 3D images of the road surfaces, limiting the disturbance on vehicular traffic and speeding up condition survey operations. In this paper, the authors present some survey tests and the related outcomes of this novel device, evidencing the applications of specific algorithms for distress detection and quantification.

In this paper, using a large database from the Long Term Pavement Performance program, the authors developed an Artificial Neural Network (ANN) to estimate the structural performance of asphalt pavements from roughness data. Considering advantages of modern high-performance survey devices in the acquisition of road pavement functional parameters, it would be of practical significance if the structural state of a pavement could be estimated from its functional conditions. To differentiate various road section conditions, several significant input parameters, related to traffic, weather, and structural aspects, have been included in the analysis. The results are very interesting and prove that the ANN represents an adequate model to evidence this relation. The papers shows the effectiveness of the adoption of a large database for the analysis of the correlation. ANN provides also better results in comparison with Linear Regression. Further, the authors trained three different ANNs to analyse the effects of modified datasets and different variables. The numerical outcomes confirm that, by using this approach, it is possible to correlate with good accuracy roughness and structural performance, allowing road agencies to actually reduce the deflection test frequency, since they are generally more costly, time consuming, and disruptive to traffic than functional surveys.

The existing international standards suggest a methodology to assign a specific functional class to a road, by the values of some features, both geometrical and use-related. Sometimes, these characteristics are in contrast with each other and direct the analyst towards conflicting classes for a road or, worse, one or more of these features vary heterogeneously along the road. In these conditions, the analyst assigns the class that, by his capability and experience, he retains the most appropriate, in a very subjective way. On the contrary, the definition of an automatic procedure assuring an objective identification of the most appropriate functional class for each road would be desirable. Such a solution would be useful, especially when the road belongs to the existing infrastructure network or when it was not realised by out of date standards. The proposed procedure regards the definition of a classification model based on Pattern Recognition techniques, considering 13 input variables that, depending on their assumed value, direct the analyst towards one of the four functional classes defined by the Italian standards. In this way, it is possible to classify a road even when its characteristics are heterogeneous and conflicting. Moreover, the authors analysed the model limitations, in terms of errors and dataset size, considering observation and variable numbers. This approach, representing a beneficial decision support tool for the decision-maker, is exploitable for both planned and existing roads and becomes particularly advantageous for road agencies aiming to optimally allocate their limited funds for specific interventions assuring the achievement of a fixed functional class.

The recent developments of road pavement survey technologies guarantee acquisition of detailed data regarding the main functional and structural indicators, at a very high frequency and levels of accuracy and precision unconceivable few years ago. The relevant information, regarding surface distresses too, is thus available in economical, high-speed and high-resolution forms, with limited disturbance on traffic and road agencies issues. However, the availability of such a mass of data poses interesting questions concerning the most efficient processing and analysis methods, for optimizing maintenance operation planning. Unfortunately, the PMS adoption is not very common and widespread, as they are significantly complicated and sophisticated, with critical consequences in their actual and intense practical use. Then, there is a need of simplifying the pavement maintenance process, by defining smart tools actually supporting the operators in the analysis and decisional phases. BIM (Building Information Modeling) procedures can absolutely represent a strategical solution. Indeed, BIM models, already widely adopted in the structural fields, have been recently introduced in the infrastructural design phases, simplifying the entire life-cycle of the construction, with representation clarity, mistake reduction, and money savings. However, although the BIM advantages have been significantly exploited in the design phases, pavement maintenance has not been directly involved in the BIM processes. Then, this paper focuses on a methodological analysis of the problem, aiming to propose a novel BIM-based approach for managing pavement maintenance. The goal is to define proper “smart objects”, based on specific relational databases, that may represent a more suitable instrument for handling pavement condition and quality information, in a user-friendly software environment. The potentialities of the modern survey technologies may be integrated and optimized in a BIM process, involving in parallel both design and maintenance.

The BIM (Building Information Modeling) approach potential in the civil engineering field opened novel scenarios in the design idea concept, from planning to executive and constructive phases. The related advantages are numerous and not only limited to a real-time interaction among the involved subjects, that can actually operate in an optimized 3D shared environment. Owing to the sharing information philosophy and to the features of various "smart objects" combined in the project, this innovation reduces potential errors and increases the effectiveness of the design solution in terms of both functionality and cost. Despite these advantages, the highway alignment design problem remains very complicated and not easy to solve without appropriate supporting tools. In recent years, several efforts have been spent in defining highway optimization procedures for helping designers in the selection of an optimal solution in compliance with numerous different constraints. Introducing these procedures in a BIM environment may represent a crucial step in the improvement of the highway design procedures, exploiting the full representation and modelling potential of the approach. In this paper, the authors present the advantages of a 3D highway alignment optimization algorithm, based on the Particle Swarm Optimization method, and its possible implementation in a BIM platform. A proper I-BIM environment can exploit the potential of the alignment optimization algorithms, simplifying the analysis of the different solutions, the final representation and the eventual manual modifications.

Pavement deformation is a critical issue in the design of pavement structures and the related mixture. Asphalt concretes may be very sensitive to this problem, in compliance with the viscoelastic behaviour of the adopted bitumen. To improve the material performance, many attempts have been made to introduce in the mixture other materials as “modifiers” or “additives” for increasing the permanent deformation resistance and the elastic modulus of the material. Among the different possible materials, polymers determined significant improvements in the road pavement performance. In this paper, the authors tested the adoption of a specifically engineered polymeric compound, in order to evaluate its effects on a generic asphalt mixture. Several tests were used to prove the effectiveness of the modification. Tests were performed not only in the laboratory, but also in an actual pavement section of the International Airport of Palermo in Sicily. Tests results prove that a proper mix-design can assure a decrease in the permanent deformations, remarkable growth of the material modulus with a reduced bitumen percentage, with economical savings. Finally, regarding fatigue resistance, the modified mixture with low bitumen content assures performance comparable to the control mix containing higher bitumen percentage. Then, the proposed application can be very useful to improve pavement performance even when using softer binder, easier to find in the Italian context.

This research proposes a fuzzy model built to predict the track paths of a motor vehicle on a two-lane road and two-way traffic. The purpose of this study stems from the awareness that the position of the vehicle within the cross-section hardly coincides with the axis of the lane but deviates from this one because of some conditions generally not provided in the road standards. To solve this problem, the authors prepared an instrumented vehicle, measuring many variables during some trials in a rural road located in Sicily, Italy. The resulting database was treated at first with subtractive clustering techniques to correctly size the membership functions and rules without the subjective help of an analyst. Therefore, the fuzzy model was built only on the basis of the measured data, and the result was the position of the vehicle within the cross-section of the examined road. This research can help the analyst to look for the real cause of user's misbehavior even when the variables involved are fully...

This paper focuses on the study of the driver's workload while driving on a rural two-lane road with different traffic flows. The aim of the research is to examine a parameter that could be representative of the driving effort, quite sensible to the external factors that cause disturbance to the regular driving activity. To solve this problem, the authors used a specific instrumented vehicle for monitoring some physiological parameters of the driver (as the eye movements and the Galvanic Skin Resistance), referring their values to the road context. The results are very interesting and confirm that knowing the workload is useful to improve the road safety only if it is related to the external context, as well as road geometry, traffic, visibility, etc. Only in this way, the road administrators can deduce proper information to plan and direct accurate and productive upgrade working operations.

The compaction of the asphalt layer is a fundamental operation in pavement construction but, at the same time, its control is very difficult. The consequences on costs, on execution time and on duration of the pavement are very relevant and, for that reason, we wanted to prepare a predictive model able to minimize the attempts, often unsuccessful, which the executor is forced to make in the early stages of the construction. Due to a very large number of variables, we could not control the phenomenon with any known physical models; so, for the purpose of this research paper, we preferred to make use of a so-called black-box linear model, calibrating it with an appropriate procedure of trials and errors.The results achieved with this model have made it possible to predict the value of the material density with a reliability of 88% that, for the number of involved variables, can be considered a satisfactory target.With this procedure and knowing the boundary conditions (characteristics of the roller and the material), it is possible to arrange the compaction very quickly, achieving a good compromise between layer density and execution times.

A civil engineering work can be performed by organizing the available resources (manpower, equipment and materials) in many different ways. Each different configuration results in a realization time and a cost that a building company has to bear. To produce reliable duration forecasts and money savings, it is essential to take into account all the uncertainties involved in the project operations. Generally, since it is impractical to process numerous uncertain variables - also undefined from a statistical point of view -, traditional probabilistic methods involve application difficulties for complex environments such as construction sites. To properly handle this issue, the authors propose in this paper the application of the Affine Arithmetic technique. This method treats the variables as intervals and returns reliable results, even when the variables are mutually dependent. The numerical example presented in the paper proves the efficiency of the procedure, even if some analytical complications are included in the analysis (dependency between variables, non-linear functions, etc.). Comparisons with Interval Analysis and traditional procedures are also provided, Adopting Affine Arithmetic, the results are reported in terms of intervals, avoiding the definition of unrealistic deterministic values that can strongly affect the operation organization. Furthermore, without increasing the problem complexity, the model admits continuous modifications (interval amplitudes, new variable dependencies, etc.) to correct and optimize the durations.

In the civil engineering field, there are usually unexpected troubles that can cause delays during execution. This situation involves numerous variables (resource number, execution time, costs, working area availability, etc.), mutually dependent, that complicate the definition of the problem analytical model and the related resolution. Consequently, the decision-maker may avoid rational methods to define the activities that could be conveniently modified, relying only on his personal experience or experts’ advices. In order to improve this kind of decision from an objective point of view, the authors analysed the operation correction using a data mining technique, called Fuzzy Clustering. This allows the analysts to represent complex real scenarios and classify the various activities according to their influence on the reduction of the total execution time. The proposed procedure provides positive results that are also in compliance with significant operational constraints, such as the control of costs and areas needed by the workers to perform the tasks. Finally, it is possible to increase the input variable number preserving the algorithm simplicity and avoiding lacks of accuracy in the final numerical outcomes.

The compaction of a hot mix asphalt depends on a number of important factors whose control, during the execution of the pavement, is complex; however it is essential to achieve the results envisaged in the design with the least possible cost. Therefore, the evaluation of the effect of these variables on the material density is important as well as their quantification in real time. This research, starting from a survey of some environmental variables, together with the hot mix asphalt density using an electrical impedance device, through the application of a neuro-fuzzy technique, proposes a procedure to classify the most important features. These results can be rapidly deduced during the paving operations; calibrations required to correct the compaction can be applied on site without waiting further time necessary for the extraction of the cores and the subsequent laboratory analysis. In this way it is possible to identify with a better precision the aspects of the environmental context requiring more attention. In addition, the model permits the inclusion of new input variables and additional data that can be recorded in following phases.

In this paper the elastoplastic fracture mechanics method to analyse the fatigue damage of the flexible pavement has been applied. This approach is an appropriate alternative for analysing the fatigue cracking damage of a road pavement, with respect to traditional methodologies based on the use of the experimental fatigue laws of the bituminous mixtures. In this regard, a numerical method to evaluate the stress intensity factor at the edge of the crack has been used and the Paris' law to analyse the crack propagation into bituminous layer has been applied. Then, a comparison with the linear elastic fracture mechanic method and with the traditional approach based on the use of the fatigue laws has been carried out. A numerical example has shown the influence of the elastoplastic properties of the bituminous materials in the phenomenon of propagation of the fracture.

In this paper, we investigated drivers’ visual behaviour while travelling a road regularly opened to traffic in order to evaluate the effectiveness of the traditional scientific models and propose, at the same time, further measures useful for understanding the complex phenomenon. As is known, drivers acquire the necessary information for knowing the road geometry by visually detecting certain areas of the surrounding context. Some models in the literature have shown in a simple and convincing way these mechanisms, but they are valid only with specific assumptions, often very restrictive, such as a two-lane road, horizontal sign clearly visible and no interaction with other vehicles. For this reason, in this study we wanted to investigate different conditions, by estimating the visual strategy of some regular drivers on a three-lane road in presence of other vehicles. The visual behaviour was surveyed with the Tobii Glasses Eye Tracker and the resulting raw data were further manipulated by us to extract more useful information for our purposes. In particular, we quantified the driver’s dedicated attention to the various elements present inside the environmental context, both static (road edges, road signs, dashboard, etc.) and dynamic (other vehicles), meaning by this term those that could potentially collide with the trajectories of our vehicle. The achieved results, highlighting the limits of validity of some recent studies, contain some proposed indexes useful to give a better understanding of the visual behaviour in order to detect any eventual weakness of the road.

Pavement cracks are considered a major indicator of pavement performance. Because traditional manual crack surveys are dangerous, time consuming, and expensive, technologies have been developed to collect high-speed pavement images, and numerous algorithms have been proposed to detect cracks on pavement surface. The latest PaveVision3D Ultra system (3D Ultra) has been implemented to achieve 30-kHz three-dimensional (3D) scanning rate for 1-mm resolution pavement surface data at highway speed up to 100 km/h (60 mi/h). This paper presents the application of a hybrid procedure for automated crack detection on 3D pavement data collected using 3D Ultra. The procedure combines three different methods, namely, the matched filtering (MF) to highlight the cracks, the tensor voting to determine the main directions of the cracks, and the minimum spanning tree to identify the crack paths. The authors provide comparisons with cracking-detection results from traditional edge detectors and reference crack maps produced by a semiautomated software. The experimental results, through performance measurements and a statistical point of view, show that the proposed algorithm is able to detect pavement cracks with high precision. Finally, this paper also discusses preliminary considerations for exploiting the MF features to evaluate the orientation of the various crack segments.

This study proposes a prediction model about the trajectories a vehicle, in isolated conditions, along a curve of a road. As we know, the road environment induces stress on users and, under certain conditions, influences driving behavior. It is of advantage then, to isolate and identify those conditions from among the numerous variables, which are actually the most significant so as to prevent or mitigate the occurrence of dangerous maneuvers. On the basis of an experiment performed using an instrumented vehicle, we collected a data base to which we subsequently applied Neuro-Fuzzy techniques for the selection of the most representative variables. We then used these data to prepare a nonlinear dynamic Hammerstein-Wiener’s model able to predict the track paths along curves. The findings were encouraging since almost all the results obtained from the validation checks proved satisfactory. This research is the first step in the identification of complex systems and could be applied in road safety measures and design of new and existing roads.

Various studies have emphasized the interesting advantages related to the use of new transition curves for improving the geometric design of highway horizontal alignments. In a previous paper, one of the writers proposed a polynomial curve, called a polynomial parametric curve (PPC), proving its efficiency in solving several design problems characterized by a very complex geometry (egg-shaped transition, transition between reversing circular curves, semidirect and inner-loop connections, and so on). The PPC also showed considerable advantages from a dynamic perspective, as evidenced by the analysis of the main dynamic variables related to motion (as well as rate of change of radial acceleration, steering speed, roll speed, and so on). In this paper, an optimization procedure using genetic algorithms (GAs) for selecting the different parameters of the PPC has been proposed. In particular, a specific algorithm defines the parameter values in order to minimize an appropriate fitness function. Besides, the final PPC can be examined from a dynamic point of view for evaluating the compliance with the comfort and safety conditions. Moreover, to simplify the geometric representation and the calculation of the dynamic variables of the PPC, using computer software, a specific and innovative routine has been specifically developed by the writers.

The study of the compaction of an asphalt mix is difficult due to the high number of variables and the non-linear nature of the relationships among them. This research was supported by an experiment in which, in addition to the survey of many environmental variables, a device for measuring electrical impedance has recorded the hot mix asphalt density during execution. Subsequently, the application of a clustering technique has allowed us to classify the most important variables in the definition of the phenomenon.

The term ‘Context Sensitive Solutions’ was adopted by the Federal Highway Administration in 1997 and is a synonym of flexibility that allows the designer to balance the safety, mobility and preservation of environmental resources. When the optimal use of design criteria produces an unacceptable solution, the correct application of design value outside the current guidelines with a particular attention to safety and legal risk is needed. In this case, a feasible alternative meets the purpose of design and is considered constructible and maintainable within social, economic and environmental constraints. Unlike in many other countries, road standards in Italy do not permit to work out a simple solution to the problem of flexibility. Specifically, one of the most debated subjects, concerning the items of the Italian Ministerial Decree (MD) 5/11/2001 confer with a designer the possibility of deviating from prescriptive obligations on condition to suggest some appropriate safety analysis. However, it does not indicate any methodology to objectively quantify removal effect from the reference values established by the rule. At this purpose, the paper suggests an analytical instrument for controlling design values outside the current guidelines applying a methodology based on interval analysis, a technique generally used for managing uncertain variables. The procedure applied to designing a planimetric curve has identified the most significant variables and produced some range in which they may be retained acceptable, though outside the limits of the geometric standard. Santrauka 1997 m. JAV Federalinė greitkelių administracija (Federal Highway Administration) patvirtino terminą,,kontekstiniai sprendimai“ (context sensitive solutions), kuris yra žodžio ,,lankstumas“ (flexibility) sinonimas, leidžiantis projektuotojui subalansuoti aplinkos išteklių saugą mobilumą ir išsaugojimą. Kai optimalus projektuojamasis kriterijus yra nepriimtinas, reikalingas tinkamas projekto vertės taikymas, atsižvelgiant į jau esamas rekomendacijas, ypač pabrėžiant saugą ir teisinį rizikos objektą Šiuo atveju galima alternatyva atitinka projektavimo tikslą ir yra laikoma naudinga bei tinkama aptarnavimui, atsižvelgiant į socialinius, ekonominius ir aplinkos apsaugos ribojimus. Kaip ir daugelyje kitų šalių, kelių standartai Italijoje neleidžia lanksčiai spręsti problemos, pateikiant paprasčiausią sprendimą Aišku, kad vienas iš labiausiai svarstomų klausimų, pateiktų Italijos Vyriausybės dekrete (MD 5/11/2001) suteikia projektuotojui galimybę nukrypti nuo norminančių ribojimų su sąlyga, kad bus pasiūlyta tinkamos saugos analizė ir sprendimas. Tačiau tai nėra metodika, galinti objektyviai išmatuoti ir įvertinti skaičiais nukrypimo poveikį nuo nustatytų atskaitinių verčių. Straipsnyje siūloma analitinė priemonė, galinti kontroliuoti projekto vertes už jau esamų gairių ribų, taikant intervalinę analizę, naudojamą tvarkant neapibrėžtus kintamuosius. Analitinė priemonė, taikyta projektuojant planimetrinę kreivę, atskleidė svarbiausius kintamuosius ir nurodė ribas, kai galima jais remtis, esant jiems už geometrinio standarto ribų. Резюме В 1997 г. Федеральное управление шоссейных дорог Министерства транспорта США подтвердило термин «контекстные решения» (context sensitive solutions), который является синонимом слова «гибкость» (flexibility). Это в свою очередь позволяет проектировщику при выполнении проекта сбалансировать между собой безопасность окружающих ресурсов, мобильность и сохраняемость. Когда оптимальный проектировочный критерий неприемлем, возникает необходимость в требуемом решении с учетом при этом уже имеющихся рекомендаций, обеспечении безопасности и правового риска проектируемого объекта. В данном случае возможная альтернатива должна удовлетворять цель проекта и быть полезной и нужной в использовании с учетом различных требований и ограничений, например, таких, как социальные, экономические и природоохранные. Дорожные стандарты Италии, как и многих других стран, не позволяют гибко решить проблему с помощью простейшего решения. Представленные в Декрете (MD 5/11/2001) правительства Италии положения дают возможность проектировщику отклониться от нормируемых ограничений при условии, что будет предложен анализ и принято решение, удовлетворяющие требуемый уровень безопасности. Однако при этом методика не позволяет объективно численно определить и оценить воздействие отклонения от установленных рекомендуемых значений величин. В статье представлено аналитическое средство, позволяющее контролировать отклонения в проекте от установленных рекомендуемых значений величин с использованием интервального анализа для конкретно неопределенных величин. Аналитическое средство применялось при проектировании планиметрической кривой. Определены важнейшие переменные и указаны границы величин, которые можно использовать за границами геометрического стандарта. Reikšminiai žodžiai: lankstumas, intervalinė analizė, projektavimo standartai, kelių standartai, sauga Ключевые слова: гибкость, интервальный анализ, стандарты проектирования, дорожные стандарты, безопасность

The aim of this paper is the proposal of an expeditious procedure to be used during the execution of an asphalt layer for improving the compaction task. This procedure, based on a fuzzy clustering technique, starts from the knowledge of some information recorded by ordinary measuring instruments and provides an aid to the decision-maker on the number of roller passes needed to achieve a specific density at a certain temperature. This result can be deduced with great rapidity during the paving operations on site without waiting for the time spent in the core extraction and in the subsequent laboratory analysis. In this way it is possible to identify more precisely which aspects of the execution have to be corrected for performing the best compaction.

This paper deals with the application of an analytical technique known as ‘interval analysis’ to the usual audits contained in international road standards. Generally, a design solution is constrained by a number of parameters (dependent on the morphology of territory, on existing conditions, on type of road, etc.) that, materially, cannot exceed certain values. Although the final choice is respectful of these constraints, the ordinary calculation techniques do not allow use of the full potential of the most critical variables. In order to determine all the possible solutions of the problem, the so-called interval analysis, which is generally used to treat uncertain problems when only the limits of existence of uncertain variables but not their probabilistic characteristics are known, was used. The application to the visibility of a horizontal curve has allowed different solutions to be identified, by starting from the knowledge of the range of existence of one or more input variables and isolating the result which was more convenient for that specific situation. This procedure is easily applicable to the design of new or existing roads, especially when one or more variables of the problem are close to the threshold imposed by the standards.

The proposed research addresses the problem of predicting driver's visual behavior. Notably, this issue is of great importance for road safety because it provides information about the true perception of the road environment. This need is particularly felt when the real situation is so complex that it cannot be represented by simple analytical audits contained in the road international standard. Therefore, with the help of an instrumented vehicle, the authors conducted some trials to identify relevant data useful to recognize the road environment as perceived by drivers. Based on this data, the authors prepared a linear model that, properly calibrated, would enable them to predict the drivers’ visual strategy. The results were encouraging, because a model so simple in structure as well as in the number of variables involved could control a very complex phenomenon, such as that of visual perception. The proposed methodology can be applied as a further control in the design of new roads and in the maintenan...