The efficacy of the application of traffic models depends on a successful process of model calibration. Microsimulation models have a significant number of input parameters that can be optimized in ...the calibration process. This paper presents the optimization of input parameters that are difficult to measure or unmeasurable in real traffic conditions and includes parameters of the driver’s behavior and parameters of Wiedemann’s psychophysical car-following model. Using neural networks, models were generated for predicting travel time and queue parameters and were used in the model calibration procedure. This paper presents the results of a comparison of five different applications of neural networks in calibrating the microsimulation model. The VISSIM microsimulation traffic model was selected for calibration and field measurements were carried out on two roundabouts in a local urban transport network. The applicability of neural networks in the process of calibrating the microsimulation models was confirmed by comparison of the modelled and measured data of traffic indicators in real traffic conditions. Methods of calibration were validated with two sets of new measured data at the same intersection where the calibration of the model was carried out. The third validation was made at the intersection in a different location. The selection of the optimal calibration methodology is based on the model accuracy between the simulated and measured data of traveling time, as well as queue parameters. The microsimulation model provides access to the raw data of observed traffic parameters for each vehicle in the simulation. The dataset of the calibrated model simulation results of all travel times of the selected traffic flow was compared with the dataset of the measured field data to determine whether the data are statistically significantly different or not.
The protection of air from pollution is one of the basic principles of sustainable development, and this article analyzes the joint impact of various types of agricultural production and traffic on ...nitrogen oxide (NOx) emissions. The goal of this research is the development of a new methodology for assessing the combined impact of different types of agricultural production, traffic load, and traffic flow structure on the emission of nitrogen oxides. For the analysis of the joint impact of traffic and agricultural production, a new impact assessment methodology was developed, which is based on two selected impact prediction models. The following two models were used to predict the impact: the BioGrace model and the microsimulation model VISSIM. The developed methodology was applied to a case study in real field conditions. The results showed that the difference in the emission of NOx gases, depending on the type of agricultural production, indicates a reduction in NOx emissions in the walnut–winter-wheat system by 30%, compared to the production of winter wheat in an open field. The statistical analysis showed that there is no statistically significant difference between NOx emissions for different vehicle arrival scenarios for the same traffic load. The results of the joint impact show that the lowest NOx emission was found in walnut orchards and counted traffic. In this example, the difference between the one-hour emission load of three different agricultural types of production and traffic is not large; however, in the cumulative load, it can lead to significant differences. Emphasizing the importance of adopting new agricultural practices and the impact of traffic and the share of freight and heavy goods vehicles in agricultural production, we position them as a proactive and sustainable response to the critical ecological and agricultural challenges highlighted in European and Croatian policy.
Children pedestrians represent road users with some specifics because of which it is important to study and take into account their traffic behaviour when traffic infrastructure is designed. Design ...should ensure and enhance their traffic safety because for decades, traffic accidents have been among the first few causes of children and adolescent mortality. Pedestrian speed is one of the important inputs when pedestrian infrastructure, especially crosswalks, is designed. On corridors where children are expected on a daily basis as independent pedestrians, the infrastructure should be adjusted to their characteristics and needs. The results of a study conducted in two Croatian cities of a similar size but of different urban and traffic conditions are presented in this paper. This study aimed at establishing and analysing children’s pedestrian speed while crossing the signalized crosswalk in the buffer area of elementary schools, mostly on primary roads in the school vicinity. Children aged 5–15 were observed, and accordingly V15, V50, and V85 speeds were established on the basis of altogether 600 measurements. Speed was established for children walking individually, in a group and supervised by adults, and of a different age, and based on their gender, the impact of infrastructural elements on their speed in traffic was also analysed. Significant differences were found between children’s speed measured in similar conditions in analysed cities and between some of the analysed groups. This fact proves that when improving conditions for children’s independent movement, it is important to consider their specifics in order to ensure safe design adjusted to children’s needs and limitations. As design speed in this paper, 15 percentile speed (V15) is considered. Suggestions on how to establish children pedestrian speed for design of routes regularly used by school children are proposed as well as some inputs elicited from the study done in Croatia are presented.
Pred projektante prometne infrastrukture stavlja se zahtjevan zadatak da pomire suprotstavljene ciljeve razvoja prometne infrastrukture prema prometnoj potražnji, a da svojim rješenjima smanje ...negativne učinke operacionalizacije sustava. Ovaj rad analizira primjenjivost mikrosimulacijskog prometnog modeliranja za analizu ekoloških i ekonomskih parametara koji se, uz funkcionalne parametre, ubrajaju u standardne kriterije ocjene varijantnih rješenja izgradnje i rekonstrukcije prometne infrastrukture. Studija slučaja napravljena je na primjeru rekonstrukcije raskrižju u urbanoj prometnoj mreži grada Osijeka. Rezultati pokazuju primjenjivost mikrosimulacija za ocjenu ekoloških i ekonomskih parametara u ocjeni varijantnih rješenja rekonstrukcije raskrižja, a brojčani pokazatelji pokazuju da se poboljšanjem funkcionalnih pokazatelja raskrižja mogu smanjiti i emisije ispušnih plinova od prometa.
Transport infrastructure designers are faced with the demanding task of balancing the conflicting goals of transport infrastructure development according to traffic demand andreducing the negative effects of the system operationalization with their solutions. This paper analyzes the applicability of microsimulation traffic modeling for the analysis of ecological and economic parameters, which, along with functional parameters, are included in the standard criteria for the evaluation of various solutions for the construction and reconstruction of traffic infrastructure. The case study was made on the example of the reconstruction of an intersection in the urban traffic network of the city of Osijek. The results show the applicability of microsimulations for the evaluation of ecological and economic parameters in the evaluation of variant solutions for the reconstruction of the intersection, and the numerical indicators show that air pollution from traffic can be reduced by improving the functional indicators of intersections.
Children pedestrians make up 30% of the total number of children injured in road traffic in the EU. Research shows that children are injured more often in the urban areas, in residential areas near ...schools and parks, often at intersections and pedestrian crossings. In this study, children’s traffic behavior was analyzed by observation of signalized pedestrian crosswalks. According to the same methodology, the research was conducted in three cities in two countries (Enna, Italy, Osijek and Rijeka, Croatia) with different urban and traffic characteristics. A total of 900 measurements were analyzed, 300 in each of the cities at 18 pedestrian crosswalks located in an urban setting in the vicinity of primary schools. A detailed statistical analysis of the influence parameters shows that, as general influence parameters, pedestrian crosswalk length, movement in a group and the age of children can be distinguished. Factors that have proven to have a significant influence on the movement of children in two of the three cities observed are gender, supervision by adults, running and cellphone use. The result can serve as a valuable input for interventions in traffic education as well as a basis for the improvement of traffic conditions at intersections where children are regularly present.
Spatial and traffic planning is important in order to achieve a quality, safe, functional, and integrated urban environment. Different tools and expert models were developed that are aimed at a more ...objective view of the consequences of reconstruction in different spatial and temporal ranges while respecting selection criteria. In this paper we analyze the application of the multi-criteria analysis method when choosing sustainable traffic solutions in the center of a small town, in this case Belišće, Croatia. The goal of this paper is to examine the possibility of improving the methodology for selecting an optimal spatial–traffic solution by combining the quantifiable results of the traffic microsimulation and the method of multi-criteria optimization. Socially sensitive design should include psychological and social evaluation criteria that are included in this paper as qualitative spatial–urban criteria. In the optimization process, different stakeholder groups (experts, students, and citizens) were actively involved in evaluating the importance of selected criteria. The analysis of stakeholders’ survey results showed statistically significant differences in criteria preference among three groups. The AHP (Analytic Hierarchy Process) multi-criteria analysis method was used; a total of five criteria groups (functional, safety, economic, environmental, and spatial–urban) were developed, which contain 21 criteria and 7 sub-criteria; and the weights of criteria groups were varied based on stakeholders’ preferences. The application of the developed methodology enabled the selection of an optimal solution for the improvement of traffic conditions in a small city with the potential to also be applied to other types of traffic–spatial problems and assure sustainable traffic planning.
•Database containing measured air permeability values of residential units has been created.•Corrective factors for input parameters for neural network learning have been determined.•A successful air ...permeability prediction model has been obtained by using neural networks.
The paper describes the need to investigate airtightness of existing residential units in order to achieve adequate energy efficiency. There is a brief explanation of the blower door method used in field testing of airtightness in residential units. The mentioned method was used to create a database of airtightness test results obtained in situ at 58 residential units in the local area. The analysis of the results of these measurements indicates that there are four input parameters, which had been previously investigated and evaluated, that had a dominant effect on the test results. The examining of the possibility of successfully predicting airtightness was conducted by applying neural networks. The response results indicate that there is potential for successful prediction of airtightness, which was confirmed by independent validation through 20 additional measurements. In order to be able to generalize the results, further research needs to be conducted, using a bigger sample of measured data, and additional configurations of neural networks need to be examined.
Design recommendations for the acceleration lane length are based on research and monitoring data made decades ago and have recently been the subject of discussions and innovations. Designing a ...highway acceleration lane differs between urban and non-urban areas by a large number of parameters. Specificities of an urban space, multimodal demands of traffic users, environmental requirements and inherited spatial relationships make optimization of the acceleration lane length a real challenge. The development of analytical, analytical-empirical and simulation methods for evaluating design solutions is generated by the desire to make the analyses performed in the planning phase as realistic as possible. Microsimulation traffic tools, such as VISSIM, enable the analysis of variant solutions and the optimization of road design elements for existing as well as for future traffic demands. This paper presents an analysis of two existing acceleration lanes on the southern bypass of the city of Osijek. Microsimulation results show that there is a potential for shortening the length of acceleration lanes in the current traffic demand conditions. Various scenarios of the increase in traffic of the main and secondary traffic flows have been analysed. The results were evaluated through the criteria of selected functional indicators, which are average delays and queue lengths. This research contributes to the methodology of applying modern simulation tools in the analysis and optimization of traffic infrastructure elements in local conditions.
Walking is the original form of transportation, and pedestrians have always made up a significant share of transportation system users. In contrast to motorized traffic, which has to move on ...precisely defined lanes and follow strict rules, pedestrian traffic is not heavily regulated. Moreover, pedestrians have specific characteristics—in terms of size and protection—which make them much more vulnerable than drivers. In addition, the difference in speed between pedestrians and motorized vehicles increases their vulnerability. All these characteristics, together with the large number of pedestrians on the road, lead to many safety problems that professionals have to deal with. One way to tackle them is to model pedestrian behavior using microsimulation tools. Of course, modeling also raises questions of reliability, and this is also the focus of this paper. The aim of the present research is to contribute to improving the reliability of microsimulation models for pedestrians by testing the possibility of applying neural networks in the model calibration process. Pedestrian behavior is culturally conditioned and the adaptation of the model to local specifics in the calibration process is a prerequisite for realistic modeling results. A neural network is formulated, trained and validated in order to link not-directly measurable model parameters to pedestrian crossing time, which is given as output by the microsimulation tool. The crossing time of pedestrians passing the road on a roundabout entry leg has been both simulated and calculated by the network, and the results were compared. A correlation of 94% was achieved after both training and validation steps. Finally, tests were performed to identify the main parameters that influence the estimated crossing time.
Smartphones have become an integral part of our everyday lives and keep us busy while doing other primary activities such as driving, cycling or walking in traffic. The problem of digital distraction ...among drivers has been largely addressed, and interest is growing also on vulnerable road users as well. In fact, high percentages of pedestrians and cyclists are accustomed to checking their devices while moving in traffic. This research links to the presented theme and aims to investigate the extent to which digital distraction in the form of social media app checking influences pedestrian behavior. The focus of the study is specifically on signalized intersections. An outdoor, eye-tracking experiment was conducted on a specific route consisting of various elements typical of urban areas. Participants were asked to walk the predefined route twice, encountering three signalized intersections: the first time they were asked to walk with their smartphone in hand, the second time without. The recordings of each participant’s route were then analyzed, examining reaction time, crossing time and speed, fixations and gaze paths. The results show a clear impact of digital devices on pedestrians’ attention by increasing their reaction and crossing times and decreasing crossing speeds. In addition, the analysis of fixations found that 82.54% of the time was devoted to the smartphone, while interest in other street elements decreased from 16.64% to 4.03%.
PDF
