Vesna Dragčević

Design of Turbo Roundabouts Based on the Rules of Vehicle Movement Geometry

This paper describes a turbo roundabout design procedure based on the rules of design vehicle movement geometry. Previous studies carried out on various junction types have shown that this design approach ensures the usage of optimal roundabout element dimensions as well as safety and comfort during driving. A five-step design procedure is suggested, including a detailed description of relevant influential parameters. They are choosing a design vehicle, implementing the initial roundabout scheme on which the vehicle swept path is analyzed, choosing a method of assigning input parameters for swept path requirements testing procedure, choosing optimal design elements of a standard turbo roundabout, and fastest path vehicle speed analysis.

Strength properties of fly ash stabilized mixes

ABSTRACT A laboratory investigation of the properties of cement-stabilized pavement base course materials consisting of sand from the river Drava stabilized by hydraulic binder made of cement and fly ash is presented. The goal of the investigation was to determine the influence of several factors on the compressive and indirect tensile strengths. The factors included: a change in the structure of the stabilized mixes, a change in the treatment temperature and the time used in the sample treatment. The hydraulic binder was prepared using different percentages of fly ash in the binder: 0% (control mix), 25%, 50%, and 75%. It was determined that the amount of fly ash strongly influences the strength of the stabilized mixes. Increasing the amount of fly ash in the binder leads to a decrease in the compressive and indirect tensile strengths.

Toward Noise Modelling in Urban Areas

Noise field measurements are the only precise method of estimating environment pollution. They are long-term and expensive and are not applicable in case of prediction of conditions caused by the new intervention in space. Independent of the bases of available data, which are sometimes very limited, and of the choice of calculation method for reliable prediction of environmental conditions, making the calculation model is an important segment. In that process it is necessary to consider specific features of the location as well as of the model of behavior of all elements in the process of noise emergence (vehicle, traffic surface, machines, devices), significantly influenced by socioeconomic and economic conditions in the country. This paper provides the calculation model for the prediction of environmental noise for three relevant locations in business and residential areas of Zagreb (Croatia) and their verification was done with regard to field measurements.

Proposal for the value of permitted tolerance on width of grooved rails

This paper describes a research in geometry of grooved rails (type Ri 60/R10). The research was carried out in the last seven years (from 1994 to 2001). The measuring of rails geometry was done before building-in of the rails in to the tramway track or during the supervision grooved rails of production in the factory. Special attention was given to the width guide of grooved rails because the technical specifications for grooved rails (VDV OBERBAU Richtlinien) have not defined permitted tolerance for a guide width of grooved rails. Therefore, some difficulties arise from this fact, during production and supervision of grooved rails in the factory. The results of research can serve as a recommendation for the value of permitted tolerance of the guide width of grooved rails. The results can also be applied as a proposal in the setting of European Standard for grooved rails.

Geometric design of turbo roundabouts

Turbo roundabouts are lately a more common choice in designing multilane roundabouts. First guidelines for geometric design of this particular roundabout layout were developed by a Dutch Information and Technology Platform CROW in 2008. Soon after, a number of European countries began to develop their own regulations on turbo roundabouts, adjusted to their traffic cultures and their local conditions. In order to present the diversity of design approaches for turbo roundabout planning in various European regions, comparative analysis of turbo roundabout design procedures described in Slovenian technical specifications, Serbian design manual, German working document, and Croatian and Dutch guidelines is made. Relevant influential parameters used in these procedures are commented. Study presented in this paper may contribute to the success of turbo roundabout planning procedure.

The Effect Of Tram Track Permanent Way Closure System On The Level Of Noise

The paper deals with the analyses results of the noise level measurements carried out on the five different types of tram track permanent way closure while varying the following key parameters: load, speed and the type of the tram vehicle. The study involves the performance of the tram vehicles that are operating in the city of Zagreb. Measurement results were used for the choice of the system of the tram track permanent way closure. In addition to the noise level, the criteria included the economy of the performance and maintenance as well. The choice refers to the tram track closure system that is not separated from the road traffic, which means that the same traffic surface is shared by the road and tram vehicles. The next closure system proved to be optimal for the tram tracks in a separated lane.

Sight distance evaluation on suburban single-lane roundabouts

U radu se obrađuje problematika preglednosti na izvangradskim kružnim raskrižjima.mDan je pregled postupaka određivanja potrebne preglednosti, prikazanih u propisima, normama i smjernicama koji vrijede u Austriji, Francuskoj, Hrvatskoj, SAD-u, Srbiji i Svicarskoj. Detaljno su prikazani utjecajni parametri i postupci određivanja polja preglednosti definirani u razmatranim dokumentima. Istaknuta je raznolikost u pristupima ispitivanju preglednosti te je dan komentar rezultata ispitivanja provedenih na teorijskom primjeru izvangradskog kružnog raskrižja.

THE ANALYSIS OF LOW NOISE PROTECTION BARRIERS INFLUENCE ON TRAM TRAFFIC NOISE LEVELS

Abstract The paper describes the analysis of tram traffic noise situation in residential areas in the vicinity of Drzic Avenue, one of the major routes between the northern and southern part of the Croatian capital city Zagreb, and the effect of low barriers placed by the tracks on tram noise mitigation. In order to evaluate the effect of planned protection measure, noise models were produced and verified with short-term field measurements. Calculations were conducted by means of noise prediction software, using European interim noise prediction method and 3D model of analyzed area. Finally, the results of noise calculations for existing tram traffic situation and planned measure of protection are presented on noise maps.

The Impact of Tram Track Fastening Systems on Noise Level

The paper presents the results of measurements of noise levels caused by traffic (tram and road traffic) in Drziceva Street in Zagreb (Croatia). Noise level measurements were conducted in cooperation with the City Office for Construction and the Zagreb Streetcar Company (ZET). The tram track in Drziceva Street represents one of the main connecting routes between the northern and southern parts of the city (a length of approximately 4km). The tram tracks are in a separate traffic area. They have been laid on a continuous concrete base and covered with crushed stone. The greater part of the tram track was constructed using the Zg 3/2 system (a direct elastic fastening system), whereas the remainder of the tram track was constructed using the DEPP system (indirect elastic fastening system). Noise level measurements were conducted at two measuring points (one measuring point was chosen for each of the fastening systems). Short-term noise level measurements were executed: two measurements in the daytime period (morning and afternoon), one measurement in the evening and one in the nighttime period. Speed and tram types were taken into consideration during result analysis, as well as geometrical irregularities of the rail running surfaces, the number and category of road vehicles and noise level protection measures already implemented. The conducted measurements have served to compare tram track fastening systems with noise level propagation when trams communicate the route. The results of the research have been of assistance in defining the extent of tram impact on noise level increase (dependent on type and speed of these) in comparison with that of road vehicles communicating the very same route. For the covering abstract see ITRD E129315.

New design procedure for four-leg channelized intersections

U radu se istražuje projektiranje kanaliziranih četverokrakih raskrižja i moguća pojednostaljenja. Provedeno je istraživanje rezultiralo novim i jednostavnijim pristupom u kojem su svi elementi raskrižja pravilno oblikovani od samog početka, tako da je potreba za kontrolom provoznosti i redefiniranjem elemenata raskrižja postala suvišna. Prikazani novi postupci projektiranja četverokrakih kanaliziranih raskrižja za kutove presijecanja osi od 60 do 90° za tegljač s poluprikolicom duljine 16.5 m.U radu se istražuje projektiranje kanaliziranih cetverokrakih raskrižja i moguca pojednostaljenja. Provedeno je istraživanje rezultiralo novim i jednostavnijim pristupom u kojem su svi elementi raskrižja pravilno oblikovani od samog pocetka, tako da je potreba za kontrolom provoznosti i redefiniranjem elemenata raskrižja postala suvisna. Prikazani novi postupci projektiranja cetverokrakih kanaliziranih raskrižja za kutove presijecanja osi od 60 do 90° za tegljac s poluprikolicom duljine 16.5 m.