Trends of globalization very often cause the emergence of phenomena that asymmetrically affect the overall sustainability of the transport system. In order to predict certain situations and ...potentially be able to manage the transport system, it is necessary to manage risk situations and traffic safety in a timely manner. This study has conducted an investigation which implies defining the level of safety of a total of nine sections of two-lane roads. The main aim of the paper is to create a new multiphase model consisting of CRITIC (The CRiteria Importance Through Intercriteria Correlation), Fuzzy FUCOM (Full Consistency Method), DEA (Data Envelopment Analysis), and Fuzzy MARCOS (Measurement Alternatives and Ranking according to the COmpromise Solution) methods for determining the level of traffic safety on road sections under the conditions of uncertainty. In order for the created model to be adequately applied, eight parameters were created, and they were classified through four inputs and four outputs. To calculate the significance of the inputs, the CRITIC method based on the symmetric correlation matrix was used, and taking into account the nature of the outputs, the Fuzzy FUCOM method based on averaged values using the fuzzy Bonferroni Mean (BM) operator was applied to determine their weights. To determine the degree of safety, the DEA model was created. After that, the Fuzzy MARCOS method was used in order to determine the final ranking of the remaining five sections of the road network. Finally, the verification of results was performed through three phases of Sensitivity Analysis (SA).
According to models commonly used in practice, the capacity of roundabouts largely depends on the value of critical headway. The value of critical headway depends on the characteristics of vehicles, ...driving conditions, and geometric characteristics of intersections, but also on driver behaviour. Driver behaviour is the result of many factors that depend on the influence of the local environment, driver habits, mentality, etc. Accordingly, to calculate the capacity of roundabouts within the op-erational and planning analyses of roundabouts more accurately, it is necessary to use data that correspond to local conditions. In this paper, the critical headway was estimated at five urban single-lane roundabouts using five methods: Harders’, Logit, Raff’s, Wu’s, and the max-imum likelihood method. In order to determine which of the stated methods provides the most realistic estimate of critical headway, a comparison of field capacity values with theoretical capacity values was performed. Based on the comparative analysis performed in MATLAB, as well as the calculation of percentage prediction error, it was found that the Harders' method provides the most accurate estimate of critical headway at observed round-abouts in two cities in Bosnia and Herzegovina. Due to the similarity in the design of roundabouts and driver be-haviour, the results obtained in this paper can be applied in the surrounding countries, i.e., Southeast Europe
Planning, designing, defining relevant parameters, and managing traffic represent essential characteristics of its sustainability and safety. However, one of th key characteristics that traffic ...planners and managers cannot always influence are the characteristics of vehicle and pedestrian traffic flows. Namely, pedestrian behavio as well as driver behavior, depend on numerous factors, which are influenced by the characteristics of the road, the environment, and socio-economic characteristics Pedestrians are the most heterogeneous group of traffic participants for whom there are no specific restrictions or conditions, as is the case for drivers. In complex traffi conditions and high traffic loads, the behavior of pedestrians can affect traffic conditions, that is, the level of service. The most complex traffic conditions for pedestrian occur at surface intersections where a limited traffic area - pedestrian crossing, is used by both vehicles and pedestrians, in accordance with traffic regulation and gener traffic rules. This paper defines the goal of determining the concept of pedestrian behavior at pedestrian crossings in different cities based on start-up time classified b gender and age groups. Intersections with counters showing pedestrian phase times and those without counters were specifically considered. A novel integrated fuzz MCDM (Multi-criteria decision-making) model was created to evaluate and rank cities based on start-up time. Fuzzy FUCOM (Full Consistency Method) was used to determin the weights of criteria, while Fuzzy ROV (Range of Value) was used to evaluate and rank cities. Different models were created on a sample of ten thousand pedestrians segmented by gender and age, for which different results were obtained through analysis. In order to verify the results, sensitivity analysis, comparative analysis, an calculated statistical correlation tests were presented. The results presented are reflected in the following. Female pedestrians in Novi Sad show a higher level o concentration and carefully observe the moment when the pedestrian signal turns green when there is no counter. Doboj represents the city with the best start-up time fo pedestrian crossings with counters, while Sarajevo holds that position for crossings without counters. It is important to point out that the sample of female pedestrians show exceptional results on the same type of pedestrian crossings, as the start-up time is around one second.
Before the left turn manoeuvre from priority approach at TWSC unsignalized intersection, the driver estimates the interval occurring in the conflict flow and chooses the one which is most acceptable ...for him. The circumstances of subjective estimations of intervals are evident in differences between minimum accepted and maximum rejected interval. The time required for evaluation of acceptable interval is presented by the service waiting time of vehicles at an intersection. With the appearance of an acceptable interval, service waiting time for vehicle tsw ends, and then starts a time for performance of the left turn manoeuvre. Left turn manoeuvre involves the crossing of turning vehicles across traffic lane of conflict traffic flow. In the case of bad subjective assessment, it is possible a conflict between vehicles at an unsignalized intersection. Left turn manoeuvre is performed in a interval between vehicles of conflict flow, and a decision about moment of starting left turn manoeuvre is subjective and based on an driver’s estimate that manoeuvre will be conducted in the interval before the arrival of the next vehicle from conflict flow. Correct subjective evaluation always reserves the safety time ts.
The current models are based on the estimation of safety time ts. This paper presents development of a detailed mathematical procedure for calculation form of safety time ts. The mathematical procedure is based on the theory of probability. Measurements at unsignalized intersections had proven applicability of the proposed model, possibility of calculation subjective safety time and high participation of safety time ts in critical gap tc (about one third). The obtained results are highly consistent with HCM.
•The first model for the safety time calculation in the left-turn manoeuvre.•Model calculates the impact of all important parameters of the subjective driver behaviour.•Research of safety time in real traffic flow at intersections.•Results of model are highly consistent with previous research and HCM.
Bus passenger transport is very important for sustainable urban mobility, and due to the characteristics of the street network, it is usually realized in the conditions of mixed traffic flow. ...Disturbances and sudden changes of traffic flow parameters occurring in the street network in a mixed traffic flow affect the disruptions in schedule and travel time of all vehicles in the traffic flow, including public transport (PT) vehicles. In order to keep to the planned schedule in the peak hours of PT lines carried out in the conditions of mixed traffic flow, the operators introduce new vehicles or reduce the vehicles’ dwell time at terminuses, which is often impossible to do. The use of a larger number of public transport vehicles increases the fuel consumption, pollutants’ emission, and the operating costs. In this paper, a network optimization model was developed for defining the influence of the change of traffic flow parameters in a mixed traffic flow on travel time of PT vehicles. The model takes into consideration uncertain time unevenness of the change of traffic flow parameters, which enables determining the optimization of travel time and defining the necessary number of public transport vehicles for the purpose of keeping to the planned schedule. In order to develop the transport model, counting and analysis of the characteristics of traffic flow at 61 intersections on the city territory were carried out. The model was tested on bus line number 4 of PT in Novi Sad. The model showed that it is possible to achieve certain savings regarding the number of vehicles with the unchanged headway, that is, the unchanged level of service which is offered to the users. With the application of the model in real traffic conditions, significant savings, as well as operating and external costs’ reduction, can be achieved, which contributes to the sustainability of public bus transport in urban environments.
Knowledge of the characteristics of speed at roundabouts is very important in design procedures, simulation models, and determining the influence of these roundabouts on traffic conditions in a ...street network. Sustainable management in the street network means the influence of all its parts on traffic conditions and travel time. In order to reliably determine roundabouts parameters in the procedures of planning and the choice of sustainable method of traffic management, it is very important to know the values of the traffic flow parameters, particularly the speeds at the entry and exit leg, as well as in the circulatory zone. This article analyses the speed characteristics in traffic flow at urban roundabouts with different geometrical characteristics in the city of Banja Luka. The applied method for traffic data collecting in this research was the method of video recording processing, which excludes any influence on driver behavior. Furthermore, statistical analysis was conducted, which established the correlation between the achieved speeds and geometrical characteristics of the intersection. Due to roundabout characteristics, the research was focused on the access, that is, the entry leg, the segment of the circulatory zone and the exit leg. The research results showed there is a significant dependence between geometrical characteristics of certain elements of the roundabout on speeds. In the further course of the research, it was proved that the variation of speeds at the segments of roundabouts significantly affects the size of time losses and emission of pollutants, i.e., parameters based on which it is possible to objectively assess the possibility of sustainable implementation of the planned solution of roundabouts of similar geometry within the street network in cities similar to Banja Luka.
Eco-driving as a concept and program is a well-developed strategy adopted to reduce fuel consumption and greenhouse gas emissions. The paper presents the findings confirming the significance of ...driver education about eco-driving (through theoretical and practical training initiatives) with the aim of reducing the negative environmental impact of road transport. During the study, the drivers were tested prior to and immediately after completing the theoretical and practical education on eco-training. According to the study findings, driver education resulted in approximately 11.71% reduction in fuel consumption and average CO2 emissions. These results, along with the findings of many other studies conducted around the world, show that driver education can result in very efficient and significant reduction in fuel consumption and CO2 emissions. Therefore, it is necessary for the drivers to undergo periodical eco-driving training with specialized coaches and well-designed programs.
Designing the crossroads capacity is a prerequisite for achieving a high level of service with the same sustainability in stochastic traffic flow. Also, modeling of crossroad capacity can influence ...on balancing (symmetry) of traffic flow. Loss of priority in a left turn and optimal dimensioning of shared-short line is one of the permanent problems at intersections. A shared–short lane for taking a left turn from a priority direction at unsignalized intersections with a homogenous traffic flow and heterogeneous demands is a two-phase queueing system requiring a first in–first out (FIFO) service discipline and single-server service facility. The first phase (short lane) of the system is the queueing system M(pλ)/M(μ)/1/∞, whereas the second phase (shared lane) is a system with a binomial distribution service. In this research, we explicitly derive the probability of the state of a queueing system with a short lane of a finite capacity for taking a left turn and shared lane of infinite capacity. The presented formulas are under the presumption that the system is Markovian, i.e., the vehicle arrivals in both the minor and major streams are distributed according to the Poisson law, and that the service of the vehicles is exponentially distributed. Complex recursive operations in the two-phase queueing system are explained and solved in manuscript.
We will prove that when uniformly distributed random numbers are sorted by value, their successive differences are a exponentially distributed random variable Ex(λ). For a set of n random numbers, ...the parameters of mathematical expectation and standard deviation is λ = n−1. The theorem was verified on four series of 200 sets of 101 random numbers each. The first series was obtained on the basis of decimals of the constant e = 2.718281…, the second on the decimals of the constant π = 3.141592…, the third on a Pseudo Random Number generated from Excel function RAND, and the fourth series of True Random Number generated from atmospheric noise. The obtained results confirm the application of the derived theorem in practice.
Procedures for the calculation of capacity of all types of unsignalized intersections, therefore roundabouts as well, represents a combination of the empirical model (exponential regression) and the ...likelihood of accepting time gaps in the priority flow by drivers who perform a minor manoeuvre. The values of the critical headway, as the minimum necessary time gap for performing the wanted minor manoeuvre, and the follow-up headway, have been given as the recommendations in the existing methodologies for capacity calculation, depending on the type of the manoeuvre. In traffic flow theory it has been known that drivers’ behaviour influences the capacity of roads and intersections, and the assessment of that influence is done through the adoption or correction of the values of certain parameters. At unsignalized intersections the influence of drivers’ behaviour is reflected through the values of critical headway and follow-up headway. The acceptance of the value of time gaps, i.e., the value of the critical headway and follow-up headway, depends on drivers’ knowledge of local conditions. This paper presents the parameter values of critical headway and follow-up headway for resident and non-resident drivers based on the analysis and statistical processing of research results. The research was conducted at four roundabouts in four towns in Bosnia and Herzegovina, and the total number of vehicles covered by the research is 31,053. In that way, it has been confirmed that the capacity of roundabouts depends on the behaviour of the alleged groups of drivers, i.e., with the increase of the level of participation of non-resident drivers in traffic flow, the roundabout capacity decreases. The model for determining the influence of non-resident drivers on the roundabout capacity was created by using multiple linear regression. If the proposed model in the procedures of traffic planning is applied, the influence of roundabouts on the level of service, sustainability, and the emission of Green House Gases (GHG) can be realistically assessed and perceived in accordance with the expected participation of resident and non-resident drivers.
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