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The temperature of asphalt layers has, in addition to loading, the most significant influence on the pavement deflections below the load and within the deflection bowl. Existing models for temperature correction factors have been developed on the basis of foreign experience and do not take into account the asphalt mixtures used in the region. The paper presents research with the aim of developing models for correction factors that can be applied in the procedures of deflection analysis and bearing capacity calculation of existing pavement structures. The research consists of three parts. The stiffness moduli of asphalt mixtures AC11s for the wearing course and AC 22sA for the base layer were obtained from their master curves, which were constructed on the basis of laboratory tests of stiffness modules. The calculation of deflection was performed by the EVERSTRESS program for three levels of flexible and semi-rigid pavement structures, with asphalt layer thicknesses from 100 mm to 210 mm. The obtained deflections were used for the calculation of the correction factor to the reference temperature of 20oC for the temperature range from 10oC to 30oC, which is considered realistic and desirable for deflection measurements on flexible pavement structures. Finally, a model for correction factors was developed and validated using neural networks. The model includes flexible and semi-rigid pavement structures, and in addition to the temperature of the asphalt layers, it also includes the thickness of the layers and the distance of the deflection from the center of the loading.

У дисертацији су разматрани проблеми комерцијалне експлоатације друмске инфраструктуре који се односе на избор одговарајућег система за наплату путарине, оптимизацију рада наплатних станица и дефинисање одговарајуће тарифне политике. При томе су развијени одговарајући модели уз помоћ којих се обезбеђује ефикасно функционисање службе за наплату путарине са једне стране и захтевани ниво услуге корисника са друге стране. Применом развијених модела и добијених резултата доносиоцима одлука се даје аргументована подршка при одлучивању о избору система за наплату путарине... This dissertation considers the issues of the commercial exploitation of road infrastructure related to selecting the appropriate toll collection system, optimizing the toll plaza operation and defining the appropriate tariff policy. In the process, appropriate models were developed to ensure both the efficient operation of the toll collection service and the required level of service provided to users. The application of the developed models and obtained results provides support to decision makers when selecting the toll collection system...

Osnovni motiv za izradu ove disertacije je potreba za većim stepenom automatizacije procesa projektovanja situacionog plana površinskih raskrsnica kroz eliminaciju iterativnog procesa ponavljanja nekoliko serija simulacija kretanja merodavnog vozila prilikom analiza prohodnosti. Disertacija je podeljena na tri dela. U prvom delu određene su realne trajektorije povlačenja vozila pomoću GNSS RTK kinematičke metode diferencijalnog pozicioniranja u realnom vremenu. Razvijena je originalna metodologija za precizno utvrđivanje niza položaja i orijentacija testnih vozila na osnovu GPS koordinata snimljenih tokom praćenja zadatih putanja na test poligonu. Predložena metodologija smanjuje greške pri snimanju trajektorija nastale usled zanemarivanja nivelacionih karakteristika kolovoza i nemogućnosti preciznog postavljanja GPS rovera u odnosu na zaobljene karoserije vozila. U drugom delu, razvijeni su matematički modeli za proračun položaja vozila sa jednim, dva i tri sloga koja prate vodeće kružne putanje, kao i nov analitički postupak za proračun položaja vozila u kome se dostiže maksimalni offtracking, odnosno, maksimalno odstupanje centra poslednje osovine vozila od vodeće putanje. Utvrđeno je da su trajektorije povlačenja vozila sračunate pomoću matematičkih modela na "strani sigurnosti" u odnosu na trajektorije iz opšteprihvaćene Halter-ove simulacije, koje su istovremeno na "strani sigurnosti" u odnosu na realne trajektorije povlačenja dobijene na osnovu eksperimentalnih merenja. U trećem delu, razvijen je softverski alat za pronalaženje optimalnih kombinacija geometrijskih parametara trocentričnih krivina koje najbolje aproksimiraju trajektorije povlačenja iz matematičkih modela. Najvažniji rezultat dobijen primenom razvijenog softverskog alata je nova geometrijska forma trocentrične krivine sa optimalnom kombinacijom geometrijskih parametara za aproksimaciju trajektorija povlačenja vozila. The aim of this dissertation is to achieve a higher level of automation when developing crossroad plans. The immediate goal is to develop and improve methods for vehicle trajectories mathematical modeling, thus eliminating repetitive vehicle movement simulations. In its first part, a new method of recording vehicles' trajectories by using a real-time kinematic differential positioning technique was developed and presented. It was revealed that the existing methods of vehicle tracking based on Global Positioning System (GPS) technology are prone to errors. Not taking into account realistic pavement morphology (grading characteristics) while converting the raw data and inaccurate positioning of GPS receivers on modern streamlined vehicle bodies have been the major sources of errors. New methods of converting recorded trajectories into real-world coordinates overcame these deficiencies. In the second part, mathematical models for calculating the positions of one, two and three unit vehicles following circular steering paths were developed. In relation to existing mathematical models, accuracy has been improved and new methods for calculating maximum offtracking were developed. It was also demonstrated that all mathematically modeled vehicle movement trajectories were on the safe side in relation to the ones obtained from the widely accepted Halter's graphoanalitical method which were, in turn, on the safe side in relation to the experimentally recorded trajectories. In the third part, software for automatic retrieval of optimal 3-centered compound curves, producing minimal offsets on the safe side from the mathematically modeled trajectories, was developed. Unlike sophisticated formulas underpinning the modeling of vehicles' trajectories, optimal 3-centered compound curves are simple shapes, well suited for an average crossroad designer.

Pri sanaciji klizišta, pojave koja je veoma česta na putevima Srbije, brojne su nepoznanice kod procene troškova radova predviđenih za njihovu stabilizaciju. Veoma su važni uticajni činioci većeg broja promenljivih (kojima se opisuju svojstva terena i dimenzije kliznog tela) na cenu konstrukcije pri saniranju klizišta. Takođe, građevinski zahvati koji se izvode u cilju poboljšanja stabilnosti padina su dosta raznovrsni, što uz različite uzroke pojave klizišta i njihove elemente, ima za posledicu široke raspone utrošenih sredstava po sanaciji. Kako je apsolutno neophodno stabilizovati ugrožene saobraćajnice ili druge objekte na nestabilnim terenima, veoma je važno, svakako i za našu državu, racionalno korišćenje sredstava koja se opravdano izdvajaju u tu svrhu. Landslides are frequent natural hazard occurrence on the road network in Serbia. During their stabilization, there are usually uncertainties regarding stabilization work price evaluation. Conditioning factors of numerous variables (that are describing the terrain properties and landslides dimensions) which are affecting the final price of stabilization are of great importance. Also, construction works that are usually performed for the purpose of slope stabilization are various, and when they are combined with different landslide triggering factors and their elements - as a consequence we have a significant discrepancy of funds that are spent for stabilization. Since absolute stabilization of landslides that are occurring across infrastructure and other objects on unstable slopes is necessary, it is very important for each country and Serbia as well to rationalize the use of budget funds that are allocated for that purpose.

Povećanje broja starijih ljudi predstavlja globalni demografski trend koji, zajedno sa urbanizacijom, donosi značajne promene u strukturi i karakteru saobraćajnih zahteva u naseljima i gradovima. Urbani saobraćajni sistemi, koji su pre svega u funkciji svojih korisnika, trebalo bi da ponude usluge koje zadovoljavaju kriterijume jednakosti i ravnopravnosti za sve učesnike. S obzirom na to da kretanje predstavlja jednu od osnovnih ljudskih potreba, jasno je da ono ne sme biti onemogućeno ili ograničeno neadekvatnim sistemskim performansama. Fenomen demografskog starenja inicirao je istraživački rad i aktivnosti koje se odnose na proučavanje uticaja ovih promena na saobraćajni proces, kao i mogućih rešenja ovog problema. Usled razlika koje postoje u karakteristikama saobraćajnih sistema i njihovih korisnika, rezultati istraživanja koja su već sprovedena i verifikovana u svetu ne mogu se jednostavno preslikati i implementirati, što je determinisalo potrebu za razmatranjem ovog problema u lokalnom urbanom okruženju. Polazeći od dosadašnjih iskustava i naučnog rada na ovom polju definisan je plan istraživanja koja je bilo neophodno realizovati da bi se adekvatno sagledala predmetna problematika. Istraživački rad je podeljen u tri celine: istraživanje karakteristika i stavova korisnika, istraživanje brzine kretanja i analiza bezbednosti starije populacije, sa posebno kreiranim metodološkim postupkom za svaki od planiranih segmenata. Fokus istraživanja bio je usmeren na one zahteve i modele koji utiču na proces i elemente saobraćajnog projektovanja u gradskim sredinama. Detaljniji uvid u poteškoće sa kojima se susreću stariji u saobraćaju pokazao je da ova starosna kategorija ima značajno veći rizik od stradanja u saobraćajnim nezgodama u poređenju sa ostalim, mlađim učesnicima u saobraćaju. Ustanovljeno je da su stariji pešaci u urbanim područjima saobraćajno najugroženija kategorija u okviru posmatrane populacije. Sa druge strane, rezultati stavova starijih korisnika pokazali da se najveći broj kretanja realizuje pešačenjem, pa su seniori pešaci stavljeni u centar istraživačkog rada. Brzina kretanja pešaka je jedan od najvažnijih projektnih i operativnih parametara koji mogu da utiču na konflikte između vozila i pešaka, bezbednost pešaka i nezgode na raskrsnicama. Svim pešacima, a posebno starijim, treba obezbediti dovoljno vremena da mogu bezbedno preći ulicu. Istraživanjem je utvrđeno da je prosečna brzina starijih pešaka prilikom prelaska ulice manja nego kod ostalih korisnika i da je neophodno preispitati i unaprediti postojeće modele inženjerskih proračuna... The increasing number of older population represents a global demographic trend, as well as the growing density in urban areas. Ageing and urbanization introduce significant changes in the structure and character of traffic demands in modern cities. Urban traffic and transportation systems, which primarily exist for the purpose of their users, should offer the equality and equity of service for all participants in the transportation process. Bearing in mind that mobility represents one of the basic human needs, it is clear that it cannot be disabled or limited by inadequate system performances. This demographic shift has initiated research and activities related to the possible impact of these changes on the transportation process, as well as on the possible solutions to this problem. Due to the differences in the characteristics of transportation systems and their users, the results of research and studies that have already been implemented and verified in the world, cannot be easily replicated and implemented. There is the obvious need to consider this problem in the local urban surroundings. On the basis of previous experience and scientific work in the field, the research methodology was defined. The research plan was requisite in order to observe the issue in an adequate manner. The research was divided into three parts: research on the characteristics and users’ opinions, research on movement speed and the analysis of the safety of elderly population. Specifically defined and presented methodological procedure was created for each of the planned segments. The focus of the research was on those requirements and models that influence the process and elements of traffic design in urban areas. A more detailed insight into the difficulties faced by older road users showed that this age group had a higher risk of fatality in road accidents compared to younger road users. In urban areas older pedestrians represent the most vulnerable category of participants within the observed population. On the other hand, the results of elderly users' views show that the largest amount of movement of older pedestrians is implemented as pedestrian movement, so senior pedestrians were the focus of the research. The speed of a pedestrian is one of the most important design and operational parameters in traffic engineering which may lead to conflicts between vehicles and pedestrians, affect pedestrian safety, and cause accidents at intersections. All pedestrians, especially the elderly, should be provided with sufficient time for crossing the street safely. The results of this study showed that the average crossing speed of elderly pedestrians was lower than that of other users and that it was necessary to estimate the existing models of engineering calculations...

Putevi predstavljaju značajne resurse i najvažnije javne investicije jedne zemlje. Putna mreža predstavlja osnovu za dobro funkcionisanje svih aspekata jedne države. U funkcionalnom sistemu puteva često je nemoguće obezbediti visok nivo usluge puteva tj. neometano i bezbedno kretanje vozila u glavnom saobraćajnom toku, uz realizovanje optimalnih brzina, kao i pristupačnost lokacijama u neposrednom okruženju u posmatranom trenutku. Pristup u fizičkom smislu predstavlja svako direktno spajanje kolovoza javnog puta sa zemljištem koje se jednom svojom stranom graniči sa putnim zemljištem. Predmet doktorske disertacije je ispitivanje uticaja pristupa na uslove u saobraćajnom toku na glavnom pravcu kroz promene brzine i vremena putovanja na deonici dvotračnog puta na prolasku kroz manje naseljeno mesto. U okviru istraživanja korišćeno je plutajuće vozilo opremljeno GPS uređajem. Zadatak je bio da plutajuće vozilo oponaša ponašanje vozila u saobraćajnom toku i preko GPS uređaja beleži promene u brzini saobraćajnog toka, sa posebnim fokusom na realne podatke o promeni brzine u slučajevima kada se vozila ulivaju na glavni putni pravac ili se sa njega izlivaju, odnosno vrše manevre sa pristupa i na pristup. Na osnovu relevantne baze podataka dobijenih istraživanjem u realnim uslovima, analizom i sintezom izvedeni su zaključci o ponašanju vozača i karakteristikama pristupa u lokalnim uslovima. U priručniku HCM (Highway Capacity Manual) 2010, uticaj broja pristupa uključen je u analizu kapaciteta i nivoa usluge dvotračnih puteva preko faktora fA, kojim je definisano da svaki pristup smanjuje slobodnu brzinu za 0,417 km/h. Kao ulazni podatak je u analizu uvršćena gustina pristupa – ukupan broj pristupa sa obe strane puta podeljen sa jedinicom dužine. Direktnim korišćenjem date metodologije iz priručnika HCM2010 za lokalne uslove dobijaju se vrednosti prosečne brzine putovanja koje u velikoj meri odstupaju od realnih vrednosti snimljenih na terenu. Osnovno je pitanje da li se na osnovu prikupljenih podataka i zaključaka donetih u okviru istraživanja može definisati metodologija za kalibraciju postupka predloženog priručnikom HCM sa ciljem približavanja izlaznih rezultata istraživanja realnim vrednostima snimljenim na reprezentativnim deonicama dvotračnih puteva u našoj zemlji... Roads are valuable resources and most important public investment of a country, therefore road network is the basis for the good functioning of all aspects of a country. According to general understanding of the functional system of roads it is often impossible to provide a high level of service (safe and undisturbed movement of vehicles on the roads) with realization of optimal speed and accessibility of given location (access) in the observed time. Access represents any direct connection to the public road from the parcel bordering it. Subject of this doctoral dissertation is determination of impacts of access on conditions in main traffic flow through travel speed fluctuation and increase in travel time on twolane highway segment passing through suburban settlement. ’Floating car’ equipped with GPS device was used in this research. The vehicle entered the traffic flow and mimicked the behavior of the drivers in a platoon of vehicles. The purpose of this empirical research was to track real data on speed changes in the chosen segment, with an emphasis on situations in which vehicles merge into or diverge from the main flow. Actual data collection enabled derivation of conclusions about the behavior of the drivers and characteristics of access in the local conditions. In given methodology in HCM (Highway Capacity Manual) 2010 for determining level of service and capacity of two-lane highways, impact of number of access-points is represented through factor fA. Each access point decreases the free-flow speed by 0.417 km/h. One of the input parameters is access density, computed by dividing the total number of unsignalized intersections and driveways on both sides of the roadway segment by the length of the segment. Direct application of HCM2010 model under local conditions for calculating average travel speed yielded value that considerably differs from the real values recorded during research. Question arose whether collected data and conclusions from research can be used for calibrating the HCM2010 model for local conditions. The point at issue is whether the number of access points as included in the analysis should depend on the traffic significance of the actual access points. Introduction of weighted access density, namely assignment of weighted value to every access point based on its impact on traffic conditions in the main flow, was the solution to this problem...