Marko Ševrović

A computer vision assisted geoinformation inventory for traffic infrastructure

Geoinformation inventories are often employed as a tool for providing a comprehensive view onto the required state of traffic control infrastructure. They are especially important in road safety inspection where, in combination with georeferenced video, they enable repeatable off-line and off-site assessments as an attractive aternative to classic onsite inspection. Nevertheless, manual assessments are tedious and time-consuming even when performed off-line, and this seriously impairs the potential of the geoinformation inventory concept. This paper therefore researches a hypothesis that suitable georeferenced video processing techniques would allow reliable automation of the following operations: i) creation of the traffic inventory from the given video, and ii) assessing the video against the state in the inventory. Prominent computer vision approaches have been rigorously and systematically evaluated and the obtained results are presented. The results seem to support the hypothesis, although further work is required for a more definite answer.

Positioning and localisation for Location-based services

Success of Location-Based Services (LBS), a subset of mobile communication services, suffers from the lack of multidisciplinary co-operation due to misunderstandings caused by deployment of unilateral development models. Here we propose the re-definition of the essential terms and processes, that results in creation of the new LBS operational model, thus allowing for the enhanced and more fruitful multidisciplinary collaboration on LBS development.

Expression of GNSS Positioning Error in Terms of Distance

This manuscript analyzes two methods for Global Navigation Satellite System positioning error determination for positioning performance assessment by calculation of the distance between the observed and the true positions: one using the Cartesian 3D rectangular coordinate system, and the other using the spherical coordinate system, the Cartesian reference frame distance method, and haversine formula for distance calculation. The study shows unresolved issues in the utilization of position estimates in geographical reference frame for GNSS positioning performance assessment. Those lead to a recommendation for GNSS positioning performance assessment based on original WGS84-based GNSS position estimates taken from recently introduced data access from GNSS software-defined radio (SDR) receivers.

Harmonization and synchronization model of interrupted traffic flows on motorways

The research in this paper focuses on harmonization and synchronization of traffic flows in the period of application of zonal temporary traffic regulation. The specific case scenario addressed in this research implicates that on both carriageways no vehicles were allowed to reside in the work zones for a significant time interval in the same time periods on both sections. In order to solve this problem, the model for harmonization of the traffic flows on dual carriageway motorways with synchronization of opposing traffic flows on both carriageways in special traffic conditions is presented. Actual traffic situation that occurred is presented in order to demonstrate the model, where intensive traffic flows were interrupted on both carriageways during extensive road works on two nearby sections. The model described in this paper has several stages. The first stage implies detailed analysis of traffic flows with computation of expected number of vehicles in the queue. The next stage in the modelling process is to calculate the queue discharge time for both directions and propose measures to optimise operating speed in order to maximize capacity. Then, a graphical method by means of two-way coordination diagram is used to synchronise stop signal timings on all closed sections. This paper shows results of a new model that was developed and implemented in real situations in most complex conditions that can occur on motorways. The research findings have shown the suitability of the proposed model. First published online 24 October 2016

Traffic flow modelling on the road network in the cities

Izvorni znanstveni clanak Planiranje cestovne prometne infrastrukture je složen proces. Jedan od najvecih problema je određivanje projektnih elemenata cestovne infrastrukture (vrsta ceste i broj prometnih traka, poprecni profil i sl). Za potrebe dimenzioniranja prometnica koriste se parametri iz strane literature s vrijednostima koje su empirijskim metodama derivirane iz lokalnih podataka o prometnom toku (najcesce sjevernoamericki gradovi). Cilj ovog rada bio je istraživanje prometnih tokova radi izrade modela koji ce pružiti mogucnost egzaktnijeg opisa lokalnih karakteristika prometnih tokova na podrucju srednjoeuropskih gradova. Istraživanje osnovnih parametara prometnog toka sastojalo se od izbora lokacije cesta, vremena snimanja, snimanja prometa, analize video zapisa istatisticke analize i proracuna osnovnih parametara prometnog toka. Posebnost provedenog istraživanja sadržana je u nacinu prikupljanja i analizi podataka za svaki prometni trak (ili kolnik) radi uocavanja razlike u vrijednostima osnovnih parametara prometnih tokova. Istraživanje je obavljeno na razlicitim gradskim prometnicama i u razlicitim prometnim uvjetima te su dobiveni osnovni parametri prometnog toka. Pomocu tih parametara napravljeni su dijagrami odnosa brzine, gustoce i propusne moci i dobivene su kumulativne funkcije parametara prometnih tokova za cjelokupnu prometnu mrežu grada. Time je omoguceno da se izrade nove jednadžbe pomocu kojih je moguce teoretski odrediti kapacitet, brzinu i gustocu toka prometnice.Razvijena metoda kao i rezultat ovog znanstvenog istraživanja pouzdan je, koristan i primjenljiv alat za određivanje kriterija propusne moci ceste i proracun vrijednosti relevantnih koeficijenata mjerodavnih za dimenzioniranje poprecnog presjeka cesta u urbanim sredinama, ali i svih ostalih kategorija cesta. Kljucne rijeci: brzina prometa; cestovna mreža; dizajniranje cestovne infrastrukture; gustoca i kapacitet; prometno modeliranje; prometni tok

Advanced method of detection of unnecessary conflicts of traffic flows

Relations between the traffic flows in intersections are one of the causes of reduced throughput. Avoiding the unnecessary conflicts and reduction of breakage of traffic flows are one of the possible significant factors that may favorably affect the increase in intersection capacity. Relationships among the traffic flows in the form of unnecessary conflicts occur mainly at intersections, and also on roads between intersections, and are caused by the organization and direction of traffic flow in the network. For advanced identification of unnecessary intersections, modern IT solutions are used as a novelty approach in research and visualisation of this phenomenon. The goal of this research is to create a computer tool based on open source technologies that use data stored in a GIS environment about the movement of the users within the transport network for identification of unnecessary conflicts by monitoring the flow of vehicles and deviations in speed. Further development and research will be focused on creating algorithms for automatic identification of unnecessary conflicts based on gathered input data.

Analytic determination of reference passenger car size for parking space dimensioning in Croatia

Dimensions of parking spaces have been subject to standardization in recent decades in the world. Different state institutions and standardization committees regulated parking space sizes based on typical passenger car size and ergonomic conditions. Most of these regulations are not following the notable growth in size of passenger cars that has been the case in the past 30 years. In that period in Croatia, a significant increase was also observed in the number of passenger cars in mid-sized and large passenger car classes thus emphasising the problem of outdated and inadequate parking space dimension standard. In this paper an analytic procedure is presented that takes into account the number and types of passenger cars registered in Croatia that leads to the determination of reference passenger car size. This reference values, as well as other relevant ergonomic standards are used to calculate the recommended parking space dimensions in Croatia. The purpose of this analysis is to produce new recommendations and suggest new design standards for parking spaces in Croatia as well as to provide analytic procedures to conduct similar researches in other areas.