A Methodological Framework to Assess Road Infrastructure Safety and Performance Efficiency in the Transition toward Cooperative Driving

There is increasing interest in connected and automated vehicles (CAVs), since their implementation will transform the nature of transportation and promote social and economic change. Transition toward cooperative driving still requires the understanding of some key questions to assess the performances of CAVs and human-driven vehicles on roundabouts and to properly balance road safety and traffic efficiency requirements. In this view, this paper proposes a simulation-based methodological framework aiming to assess the presence of increasing proportions of CAVs on roundabouts operating at a high-capacity utilization level. A roundabout was identified in Palermo City, Italy, and built in Aimsun (version 20) to describe the stepwise methodology. The CAV-based curves of capacity by entry mechanism were developed and then used as target capacities. To calibrate the model parameters, the capacity curves were compared with the capacity data simulated by Aimsun. The impact on the safety and performance efficiency of a lane dedicated to CAVs was also examined using surrogate measures of safety. The paper ends with highlighting a general improvement with CAVs on roundabouts, and with providing some insights to assess the advantages of the automated and connected driving technologies in transitioning to smarter mobilit

Assessing the Environmental Performances of Urban Roundabouts Using the VSP Methodology and AIMSUN

In line with globally shared environmental sustainability goals, the shift towards citizen-friendly mobility is changing the way people move through cities and road user behaviour. Building a sustainable road transport requires design knowledge to develop increasingly green road infrastructures and monitoring the environmental impacts from mobile crowdsourced data. In this view, the paper presents an empirically based methodology that integrates the vehicle-specific power (VSP) model and microscopic traffic simulation (AIMSUN) to estimate second-by-second vehicle emissions at urban roundabouts. The distributions of time spent in each VSP mode from instantaneous vehicle trajectory data gathered in the field via smartphone were the starting point of the analysis. The versatility of AIMSUN in calibrating the model parameters to better reflect the field-observed speed-time trajectories and to enhance the estimation accuracy was assessed. The conversion of an existing roundabout within the sample into a turbo counterpart was also made as an attempt to confirm the reproducibility of the proposed procedure. The results shed light on new opportunities in the environmental performance evaluation of road units when changes in design or operation should be considered within traffic management strategies and highlighted the potential of the smart approach in collecting big amounts of data through digital communities

On the vegetation of Mosor

Im vorliegenden Beitrag wird ein Überblick über die Vegetation des Mosor-Gebirges, die sämtlich zu der mediterranen Region gehört, gegeben. Dies hängt von den klimatischen Verhältnissen bzw. von der geographischen Lage des Mosor-Gebirges, das gänzlich im Hintergrund des zentralen Teiles des mittleren immergrünen Gebietes Kroatiens verläuft, ab. Gewisse Pflanzengesellschaften und einige Pflanzenarten befinden sich hier auf der Nordwest- bzw. Südgrenze ihres Verbreitungsgebietes.Mosor se s obzirom na svoj fitogeografski položaj odlikuje nekim specifičnostima u biljnom pokrovu. Iako ima visinu od 1340 m/nm, vegetacija na Mosoru pripada u cijelosti mediteranskoj regiji. Šumska zajednica Carpinetum orientalis adriaticum zauzima ondje položaje od 400 do 900 m/nm, a zajednica Seslerio-Ostryetum od 900 m/nm naviše. Na obroncima Mosora zajednica Andropogoni-Diplachnetum serotinae dosiže, koliko je dosad poznato, najjužniju granicu svoje raširenosti. S druge strane, zajednica Erico-Cistetum cretici i Brachypodio-Trifolietum stellati imaju, prema dosadašnjim istraživanjima, na području Mosora i široj okolici Splita svoju sjevernu granicu raširenosti. Isto tako, po podacima iz literature, zajednica Campanulo-Moltkietum petraeae ima na Mosoru (uz Kozjak i Dinaru) svoju sjeverozapadnu granicu. Inače biljni pokrov Mosora, iako jako utjecajan, odlikuje se gotovo svim najznačajnijim tipovima vegetacije mediteranske regije.The papeir gives a short survey of the vegetational cover of Mosor, starting from climatozonal vegetation to the various stages of its degradation. In respect to its phytogeographic position, the mountain of Mosor has certain specific features in its vegetational cover. Although the mountain is 1340 m high, the vegetation of Mosor belongs entirely to the Mediterranean region. The forest community Carpinetum orientalis adriaticum is situated here at places between 400 to 900 m above sea, and the community Seslerio-Ostryetum from 900 m upwards. On the slopes of Mosor, the community Andropogoni-Diplachnetum reaches, as far as it is known today, the southernmost border of its distribution. On the other hand, the communities Erico-Cistetum cretici and Brachypodio-Trijolietum stellati reach, according to current investigations, their northern border in the area of Mosor and the wider surroundings of Split. Also, according to the literature, the community Campanulo-Moltkietum petraeae has its north-western border at Mosor (together with Kozjak and Dinara mts). Otherwise the vegetational cover of Mosor, although of great influence, is characterized by all the most significant types of the vegetation of the Mediterranean region

The distinguish vehicle groups speed analysis on roundabouts

W artykule przedstawiono wyniki badań prędkości pojazdów w czasie przejazdu przez skrzyżowanie typu rondo. Na tym typie skrzyżowań prędkość pojazdów zależy od parametrów geometrycznych ronda oraz od wartości natężeń ruchu. Artykuł prezentuje wyniki badań własnych autorki.The results of research of distinguish vehicle groups speeds on roundabouts have been presented in his article. The vehicles speeds on roundabouts depends on geometrical parameters and on vehicle traffic volumes on particular elements of roundabouts. This article presented results of author own researches

Architecture of intelligent transportation systems in the world and in Poland

The main objectives of all the types of implementation in the field of ITS include facilitation of road traffic that results from efficient utilization of the network of roads, improving road safety and efficient services for travellers. The scope of activities within ITS systems includes road traffic management, demand management, support for management of public transportation, information for passengers, management of vehicles’ fleet, management of incidents and support for rescue teams, advanced technologies inside vehicles and problems of electronic payments and collection of tolls. The ITS applications necessitates development of a strategic basis that regulates the principles of design, implementation and decision-making. Such a basis is provided by ITS architecture. This paper presents the standardization requirements and the structure of services in terms of ITS, discusses the organizational questions concerning architecture and presents current state in terms of development of the national ITS architectur

The comparative analysis of algorithm of capacity calculation used on the world

W artykule zaprezentowano przegląd istniejącej w różnych krajach świata bazy oprogramowania, która służy do obliczania przepustowości skrzyżowań typu rondo. Zebranie tego typu danych pozwoliło na budowę własnego oprogramowania komputerowego, służącego do obliczania przepustowości rond.The selected different existing on all over the world software for roundabouts capacity calculation and traffic flows simulation have been presented in the article. This kind of gathered data to permitted built own software for small roundabouts capacity calculation

The review of capacity formulas for small roundabouts

W artykule przypomniano i zestawiono metody obliczania przepustowości małych rond, stosowane w różnych krajach oraz przedstawiono zmiany, jakie wprowadzono w 2004 roku do metody obliczania przepustowości rond, obowiązującej w Polsce.This article reviews capacities formulas coming from different countries. The significant studies have been done on the world which developed methodologies for evaluation the functional performances of roundabouts. Capacity and delay are indicators used by most countries to assess roundabout performance. The substitutions in Polish metod in 2004 have been presented in this article too

The determinants of the speed of vehicles passing through the intersection with circular movement

W artykule przedstawiono geometryczne determinanty prędkości pojazdów poruszających się w obszarze skrzyżowań z ruchem okrężnym wraz z charakterystyką wybranych sposobów zarządzania prędkością.The paper presents the geometric determinants of the speed of vehicles passing through the intersections with circular movement with characteristics of selected speed managements methods

Turbo roundabouts signing and marking - current situation in Poland

Turbo roundabouts operating in Poland from not long time. Turbo roundabouts are one of kind of multilane roundabouts. Proper signing and marking multilane roundabouts is lacking in Poland. This signing and marking should completely emphasizing circular character of this kind of intersections and also would facilitate in the conviction that selected lane is proper and that this selected vehicle trajectory is also appropriate. The current state of marking and signing of turbo roundabouts operating abroad and in Poland have been presented in this article