FASTEST PATH VEHICLE SPEED ANALYSIS AT STANDARD TURBOROUNDABOUTS WITH VARIOUS APPROACH LEG POSITIONS

In previous studies, a new (improved) turboroundabout design approach based on the rules of the design vehicle movement geometry was proposed, and the optimal design of elements of standard turboroundabouts for various design vehicle scenarios, circulatory roadway radii, and approach leg positions was defined. Within the scope of this research, the applicability of the current Dutch calculation model for fastest-path vehicle speed analyses at standard turboroundabout schemes designed by a previously described procedure was examined. Research results have shown that this Dutch calculation model does not apply to standard turboroundabouts whose approach legs are aligned under various angles and translatory shifted regarding the roundabout geometric center, and therefore, should not be used for speed analyses at this roundabout type until a new calculation model, which corresponds to the real traffic situation, is developed

Toward environmental noise estimation according to the road surface characteristics and traffic volume

U radu su dani prvi rezultati istraživanja koje ima za cilj analizirati mogućnost relevantne ocjene stupnja smetnji uzrokovanih bukom od prometa na osnovu parametara koje uprave za ceste redovito prikupljaju. To su za opis površinskih svojstva kolnika ravnost (IRI100), tekstura i vizualni pregled stanja dan PCI-indeksom te prometno opterećenje koje uključuje i strukturu prometnog toka. Pri tome bi uz dosadašnje parametre pri donošenju odluke o rekonstrukciji bilo potrebno uključiti i ocjenu stanja bučnosti. Na taj način bi i stanje bučnosti u okolišu, ne mijenjajući uvriježenu praksu, moglo postati još jedan važan čimbenik prilikom donošenja odluke o rekonstrukciji postojećih prometnica.The paper gives the first results of the research aimed at analysing the possibility of the relevant estimation of the level of disturbance caused by traffic noise on the basis of parameters collected regularly by road administrations. For the description of road surface characteristics these are road evenness (IRI100), road texture and visual assessment of pavement condition given by the PCI-index, as well as the traffic load including the structure of the traffic flow. When making a decision about the reconstruction, together with already included parameters, the environmental noise estimation should also be taken into consideration. In doing so, environmental noise conditions would, without altering standard procedure, become another important factor in deciding about the reconstruction of the existing roads

MJERE ZA SMANJENJE PROMETNE BUKE NA PRIMJERU GRADA OSIJEKA

Noise pollution is a major environmental problem in urban spaces worldwide. The first step toward noise abatement is determining and evaluating noise levels in order to best prioritize and implement protective measures. The city of Osijek, as is obligated by law and the European Directive, has done this by creating a noise map. In this paper, we present measures for noise abatement, showing some of the measures implemented in Osijek based on their noise map, and review possible methods for abating noise in the most vulnerable areas.Zagađenje bukom danas je jedan od glavnih, u svijetu prisutnih problema zagađenja okoliša i urbanog prostora. Prvi korak ka smanjenju razina buke je utvrđivanje i ocjena razina buke kako bi se mogli definirati prioriteti za provedbu mjera zaštite. Grad Osijek, budući da je dužan prema Zakonu o zaštiti od buke i Direktivi Europskog parlamenta, izradio je kartu buke koja prikazuje razine buke i njihovu prostornu distribuciju. Ovaj rad prikazuje mjere za zaštitu od buke te neke od mjera provedene u gradu Osijeku i, na osnovu stanja utvrđenog kartom buke, razmatra mogućnosti provedbe mjera za zaštitu od buke najugroženijih područja

ASSESSMENT OF NOISE MITIGATION MEASURES IN URBAN AREAS

U radu je na primjeru Masarykove ulice smještene u užem centru grada Zagreba prikazan postupak ocjene učinkovitosti različitih mjera za smanjenje razina buke koje se odnose na upravljanje prometom. Analiza stanja bučnosti za šest različitih scenarija provedena je metodom računalnog modeliranja u specijaliziranom računalnom programu za predviđanje razina buke LimA, prilikom čega je definiran onaj optimalni koji je rezultirao najvećim smanjenjem razina buke u Masarykovoj ulici te najmanjim povećanjem razina buke u okolnim ulicama. Rezultati proračuna validirani su kratkotrajnim mjerenjima razina buke na terenu u dnevnom, večernjem i noćnom periodu.Within the scope of this study, the assessment of effectiveness of various traffic management and engineering noise mitigation measures at Masarykova Street located in the narrower centre of the city of Zagreb was made. Noise analyses were carried out by means of noise modelling procedure using the specialized noise prediction software LimA. Six different noise mitigation scenarios were observed, and optimal one regarding the amount of noise reduction in Masarykova Street and the amount of noise increase in adjacent streets was defined. Noise modelling results were validated by short term noise measurements carried out in day, evening, and night periods

STRENGTH PROPERTIES OF FLY ASH STABILIZED MIXES

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

Noise level determination in train station zones

Određivanja stanja bučnosti u zonama željezničkih kolodvora svodi se na izradu modela proračuna što je zahtjevan postupak zbog potrebnog prikupljanja velikog broja podataka o utjecajnim parametrima. Opisan je postupak optimizacije izrade modela. Uspoređeni su rezultati proračuna prema mjerenjima na terenu na dva reprezentativna primjera. Rezultati dobiveni opisanim postupkom u odnosu na mjerenja na terenu pouzdani su, što je nužno za donošenje odluke o mjerama zaštite od buke.Determination of noise levels in train station zones is based on preparation of analysis models, which is a very demanding procedure because of a multitude of parameters that have to be collected in the process. The model optimization procedure is described. Calculation results are compared with on site measurements using two representative examples. In comparison with on site measurements, results obtained using the described procedure have proven to be reliable, which is indispensable for making appropriate decisions on measures to be taken in the sphere of noise protection

Sight distance evaluation on suburban single-lane roundabouts

U radu se obrađuje problematika preglednosti na izvangradskim kružnim raskrižjima. Dan je pregled postupaka određivanja potrebne preglednosti, prikazanih u propisima, normama i smjernicama koji vrijede u Austriji, Francuskoj, Hrvatskoj, SAD-u, Srbiji i Švicarskoj. 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 issue of sight distance evaluation on suburban single-lane roundabouts is analysed. An overview of regulations, standards and guidelines applied in Austria, France, Croatia, USA, Serbia, and Switzerland, which describe procedures for determining the necessary sight distance, is given. Influential parameters for defining clear vision areas for intersections, defined in the aforementioned documents, are presented in detail. An emphasis is placed on the diversity of sight distance evaluation approaches, and test results obtained on a theoretical example of a suburban roundabout are commented on

Review of European regulations related to road traffic noise

Prikazana je europska regulativa vezana za buku od cestovnog prometa kao najvećem izvoru buke od prometa. Razmatrane su metode proračuna razine buke koje se najčešće primjenjuju u Europi. Analizirana je mogućnost primjene razmatranih metoda proračuna u Hrvatskoj, koja svoju regulativu nastoji uskladiti s europskim preporukama. Prikazane su smjernice europske unije vezane za usklađivanje postojećih metoda proračuna razine buke u cilju dobivanja jedinstvene europske metode.European regulations related to road traffic noise, which is the greatest source of traffic noise, are presented. Noise calculation methods most frequently used in European countries are examined. Authors analyze the possibility of using such methods in Croatia where attempts are currently made to harmonize national regulations with European recommendations. European Union guidelines for harmonization of existing noise level calculation methods, issued to foster establisment of an uniform European method, are also presented

Impact of vertical traffic calming devices on environmental noise

Sve veći broj stanovnika u urbanim sredinama izložen je štetnom djelovanju buke okoliša, koja u značajnoj mjeri narušava njihovo zdravlje i kvalitetu života. Dominantan izvor buke okoliša u takvim područjima je cestovni promet, a jedna od učestalo primjenjivanih mjera za smanjenje razina buke je smanjenje brzine vožnje. U radu je analizirano kako oprema za smirivanje prometa, koja se uobičajeno primjenjuje radi povećanja sigurnosti prometa, utječe na smanjenje razina buke. Analiza je provedena na sedam dvotračnih dvosmjernih gradskih cestovnih prometnica na kojima su ugrađeni različiti tipovi umjetnih izbočina i uzdignutih ploha.Increasing numbers of people living in urban areas are being exposed to harmful action of environmental noise, which severely affects their health and quality of life. The predominant source of environmental noise in such areas is road traffic, and a frequently used measure to curb down this noise involves reduction of driving speed. The influence of vertical traffic calming devices, normally used to improve traffic safety, on the degree of noise reduction, is analysed in this study. The analysis was carried out on seven urban two-lane two-way roads, on which various types of speed bumps and speed humps are installed

Mitigation measures for traffic noise abatement in urban areas

U radu su cjelovito prikazane mjere za smanjenje razine buke od prometa. Navedeni su osnovni uzroci nastajanja povišenih razina buke od cestovnog prometa i prometa prisilno vođenih vozila. Opisane su uobičajene mjere koje se primjenjuju u poslovno-stambenim zonama gradova većine europskih zemalja. Kritički je uspoređena primjena razmatranih mjera u Hrvatskoj, u odnosu na one koje se poduzimaju u zemljama članicama Europske Unije, posebice one koje se odnose na urbane sredine.Traffic noise abatement measures are methodically presented in the paper. Principal causes of high noise levels generated by road traffic and track guided vehicles are depicted. Mitigation measures normally used in office-residential urban areas of most European countries are described. The use of such measures in Croatia is critically compared with those used in European Union member countries and, at that, a special emphasis is placed on urban agglomerations