Прегледај по Аутор "SUBOTIĆ, MARKO"

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    CAR EQUIVALENTS DEPENDENCE ON THE LONGITUDINAL ROAD GRADIENT ON TWO-LANE ROADS IN BOSNIA AND HERZEGOVINA
    (Faculty of Transport Sciences, University of Zagreb, 2017) SUBOTIĆ, MARKO; TUBIĆ, VLADAN
    The main objective of this paper, based upon the extensive empirical research of free flow in local conditions, is to quantify the unfavourable impact of the flow structure on the road capacity using PCE (Passenger Car Equivalent) values as a function of longitudinal grade. Based on literature reviews and empirical research, it has been proved that the PCE value for all vehicle classes is directly correlated with the road gradient. The PCE values in free flow conditions have been determined for the approved vehicle classes. Based on the measured values, models for determining the average PCE value depending on the upward grade on two-lane roads have been developed. Comparison of the developed models in conditions of free traffic flow with the Highway Capacity Manual (HCM) models has shown lower PCE values in this research. Models for the percentage of PCE values PCE15%, PCE50% and PCE85% have also been established.
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    NEW APPROACH TO ESTIMATING THE SATURATION FLOW RATE OF A SHARED LANE WITH PERMITTED LEFT TURNS
    (Faculty of Traffic Sciences, University of Zagreb, 2020) RADIČEVIĆ, VELJKO; KRSTANOSKI, NIKOLA; SUBOTIĆ, MARKO
    The estimation of the saturation flow rate is of utmost importance when defining the signal plan at intersections. Because of the numerous influential factors, the values of which are hard to be determined, the subject problem is to be regarded as an extremely complex one. This research deals with the estimation of a saturation flow rate of a shared lane with permitted left turns. The suggested algorithm is based on the application of the artificial neural networks where the data for training are received by simulation. The results obtained by the neural networks are compared with multiple linear regression and the known HCM 2010 approach for determining the saturated flow of a shared lane. The testing data have shown that the approach based on the artificial neural networks foresaw statistically significantly better values than the ones obtained by multiple linear regression, with an error of 27 veh/h against 49 veh/h. The HCM 2010 approach is significantly worse than the two others included in this research. The ways of the future development of the suggested method could include additional factors, such as the grade of the traffic lane, the proximity of the bus stops, and others.
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    PASSENGER CAR EQUIVALENTS ON DOWNGRADES OF TWO-LANE ROADS
    (Riga Technical University (Latvia), 2020) SUBOTIĆ, MARKO; STEVIĆ, ŽELJKO; SOFTIĆ, EDIS; RADIČEVIĆ, VELJKO
    In this paper, empirical research about Passenger Car Equivalents (PCEs) on the longitudinal downgrade of two-lane roads in Bosnia and Herzegovina has been conducted in order to determine the influence of vehiclestructure under free traffic flow conditions. The research has been carried out considering the classes of vehicles at cross-sections on the downgrade of two-lane roads. As a result, the negative influence of vehicle structure under free traffic flow conditions using passenger car equivalents (PCEs) has been determined. The results show that on the downgrade of two-lane roads, the value of passenger car equivalent decreases from the level terrain to the boundary minimum value for the determined downgrade g = − 3.00%, a fter which its value starts to increase slightly. Based on the obtained values, the models calibrated with a second-degree polynomial have been developed to determine the average value of passenger car equivalent as a function of its boundary value. The paper also compares the results obtained by the developed models with the models from the Highway Capacity Manual under free traffic flow conditions. In addition, models for the percentage values of PCE15%, PCE50% and PCE85% have been established