Abstract

Discussions of autonomous land vehicles often invoke the example of air traffic, where the autopilot is responsible for steering except for take-off and landing. The question arises: what can we learn from air traffic? What autonomously flying aircraft and autonomously driving vehicles have in common is that the pilot or driver bears the final responsibility. But, there are a number of differences between road traffic and air traffic (besides their type of locomotion) that make transferring the systems from one to the other impractical. Document type: Part of book or chapter of book

Abstract

Does consideration of average speed distributions on roads-as compared to single mean speed-lead to different results in emission modelling of large road networks? To address this question, a post-processing method is developed to predict mean speed distributions using available traffic data from a dynamic macroscopic traffic model (Indy) that was run for an actual test network (Amsterdam). Two emission models are compared: a continuous (COPERT IV) and a discrete model (VERSIT+macro). Computations show that total network emissions of CO, HC, NOx, PM10 and CO2 are generally (but not always) increased after application of the mean speed distribution method up to +9%, and even up to +24% at sub-network level (urban, rural, motorway). Conventional computation methods thus appear to produce biased results (underestimation). The magnitude and direction of the effect is a function of emission model (type), shape of the composite emission factor curve and change in the joint distribution of (sub)-network VKT (vehicle kilometres travelled) and speed. Differences between the two emission models in predicted total network emissions are generally larger, which indicates that other issues (e.g., emission model validation, model choice) are more relevant. © 2007 Elsevier Ltd. All rights reserved.

Abstract

Nowadays, city streets are populated not only by private vehicles but also by public transport, fleets of workers, and deliveries. Since each vehicle class has a maximum cargo capacity, we study in this article how authorities could improve the road traffic by endorsing long term policies to change the different vehicle proportions: sedans, minivans, full size vans, trucks, and motorbikes, without losing the ability of moving cargo throughout the city. We have performed our study in a realistic scenario (map, road traffic characteristics, and number of vehicles) of the city of Malaga and captured the many details into the SUMO microsimulator. After analyzing the relationship between travel times, emissions, and fuel consumption, we have defined a multiobjective optimization problem to be solved, so as to minimize these city metrics. Our results provide a scientific evidence that we can improve the delivery of goods in the city by reducing the number of heavy duty vehicles and fostering the use of vans instead. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish MINECO and FEDER projects TIN2014-57341-R, TIN2016-81766-REDT, and TIN2017-88213-R. University of Malaga, Andalucia TECH. Daniel H. Stolfi is supported by a FPU grant (FPU13/00954) from the Spanish MECD. Christian Cintrano is supported by a FPI grant (BES-2015-074805) from Spanish MINECO. Document type: Part of book or chapter of book

Abstract

GPS navigators are now present in most vehicles and smartphones. The usual goal of these navigators is to take the user in less time or distance to a destination. However, the global use of navigators in a given city could lead to traffic jams as they have a highly biased preference for some streets. From a general point of view, spreading the traffic throughout the city could be a way of preventing jams and making a better use of public resources. We propose a way of calculating alternative routes to be assigned by these devices in order to foster a better use of the streets. Our experimentation involves maps from OpenStreetMap, real road traffic, and the microsimulator SUMO. We contribute to reducing travel times, greenhouse gas emissions, and fuel consumption. To analyze the sociological aspect of any innovation, we analyze the penetration (acceptance) rate which shows that our proposal is competitive even when just 10% of the drivers are using it. Spanish MINECO project TIN2014-57341-R (http://moveon.lcc.uma.es). FPU grant (FPU13/00954) from the Spanish Ministry of Education, Culture and Sports. University of Malaga. International Campus of Excellence Andalucia TECH.

Abstract

It is very complex to assure the dynamics of traffic networkin urban environment because of the intensity of traffic flowsand the limited space in the urban area. Signalized intersectionsare undoubtedly very important and frequent element inroad traffic network in urban regions, which greatly influencesthe traffic flow dynamics on each section as in the whole trafficnetwork. The time (delay) a vehicle needs to drive through anintersection directly influences the travel comfort, fuel consumption,traffic pollution and so on. There are many methodsfor dimensioning signalized intersections in the world literature.One of the most applied methods is the HIGHWAY CAPACI1YMANUAL (HCM) 2000 which is based on competentinput traffic flows and other characteristics of traffic signalregulations. The intention of this paper is to establish whetherwe can use the HCM 2000 method directly in the Slovenian realenvironment. Based on the established methodology of researchand limited number of delay measurement in real environmentintersections, there have been some deviations. Thecompletion of the level of service criterion for signalized intersectionshas been proposed, with the intention for more suitabilityestimation in the realistic environment. Zagotoviti dinamično odvijanje prometa na urbanem cestnem omrežju je vsled intenzitete prometnih tokov in omejenega prostora v mestih zelo kompleksno. Križišča s svetlobno signalnimi napravami so nedvomno pomemben dejavnik, ki pogojuje funkcionalnost omrežja. Čas, ki ga vozilo potrebuje za prevoz križišča neposredno vpliva na udobnost potovanja, porabo goriva in posledično na onesnaževanje okolja. V svetovni literaturi je zaslediti dosti metod za dimenzioniranje semaforiziranih križišč. Ena najpogostejše uporabljenih metod je HCM 2000, ki temelji na merodajnih vhodnih prometnih tokovih ter drugih značilnosti tovrstnih prometnih ureditev. Namen članka je preveriti, ali je moč predlagano metodo direktno uporabiti v slovenskem realnem okolju. Na osnovi vzpostavljene metodologije raziskovanja in omejenemu številu meritev zamud vsled signalnih naprav v križišču, so bila ugotovljena določena odstopanja. Predlagane so dopolnitve kriterija za določitev nivoja usluge za križišča s svetlobno signalnimi napravami, ki ustrezneje opredeljujejo dejansko stanje v realnem prometnem prostoru.

Abstract

The use of road vehicles is increasing, the benefits they afford have been progressively diminished by external costs. Whereas traffic increases as we approach the centre, the road and open space decreases. The greater specialisation allows the city growth in size and in traffic attraction. In this way urban growth feeds itself. Inter-urban transport facilities also become more extensive. Growth in size of the city generates greater amounts of traffic and can eventually give rise to agglomeration diseconomies. Higher transport costs, offices and shops, attracted by the accessibility of central locations, gradually replace residential uses, people being forced to seek housing in the suburbs. As the urban area expands and offices in the city centre are built denser and higher, traffic congestion increases. This may result in the fall in central land values, since accessibility diminishes with the saturation of transport network. Increased pollution takes various forms as noise, smoke and overcrowded housing in the centre, urban decay in the transitional zone as commercial development is anticipated. Uporaba cestnih vozil narašča, korist, ki so jih vozila prinesla pa se pospešeno zmanjšuje zaradi eksternih stroškov, povzročenih s stroški. Kjer promet narašča, predvsem v mestnih središčih, se zmanjšuje prostor na cestah in na javnih površinah. Večja specializacija mestnih središč omogoča njihova rase po obsegu in prometni privlačnosti. Na ta način hrani urbana rast sama sebe. Notranje urbana transportne naprave postajajo man) uporabne. Rast mesta po velikosti generira obseg in število vozil, s tem prometne zgostitve, kar vodi k ekonomskim težavam.. Visoki transportni stroški, obseg poslovnih prostorov in trgovin, ki se veča s privlačnostjo zaradi dostopnosti centralnih območij, postopoma zamenjujejo stanovanjsko gradnjo v središčih mest, in ljudje so prisiljeni iskati bivališča v primestnih predelih. Zaradi tega se mestna središča še bolj gosto in visoko pozidujejo, narašča pa prometna zgostitev. Vse to prispeva postopoma k manjši vrednosti stavbnih zemljišč v središčnih območjih, saj je dostopnost središč vse manjša zaradi vse večje obremenitve prometnic. Veča se onesnaževanje vseh vrst hrupa, emisij vseh vrst, veča se prenaseljenost središč, s tem je urbani razkroj območij poslovnih dejavnosti zagotovljen.

Abstract

The market offers various computer programs for simulating traffic flows at level intersections whose mathematical background is not known to the end users. Thus the user only enters the data without being aware of how the program works. The results obtained cannot be evaluated properly, which may lead to subjective decisions. The paper presents some simple mathematical alternatives which are used to determine the length of a left-turn lane in a level intersection. Na trgu je danes več različnih računalniških programov za simulacijo prometnih tokov v nivojskih križiščih, ki temeljijo na matematičnem ozadju, ki pa je načeloma neznano končnemu uporabniku programa. Uporabnik večinoma vnaša vhodne podatke brez, da bi poznal model in matematične postopke, ki privedejo do končnih rezultatov. Končnih rezultatov tako ni možno ovrednotiti, kar pa lahko privede do subjektivnih odločitev. V prispevku so prikazane enostavne alternativne matematične možnosti za določitev potrebe po uvedbi ločenega pasu za leve zavijalce in dolžine le-tega.

Abstract

Single-lane roundabouts may face the problems of getting crowded and empty in their circulatory roadway due to a strong stream of pedestrians and/or cyclists. Vehicles at the roundabout entries or exits have to provide the right of way over pedestrians and/or cyclists. Therefore, it comes to disturbances and traffic jams. If there are jams at the entry carriageway, vehicles are unable to get into roundabouts. If there are jams at the exit carriageway, vehicles are not able to leave the roundabout. When the length of vehicle platoon at the exits so long that it reaches the preceding entry, the roundabouts suffer from getting fully overcrowded. The paper presents the methodology of calculating the reduction of the roundabout capacity due to the pedestrian or cyclist stream. The method of calculating the reduction of the roundabout capacity with the disturbed streams may be used for roundabouts in urban environments, where the strength of the cyclist or pedestrian streams is not negligible. V krožnih križiščih z enim voznim pasom v krožnem toku lahko, zaradi močnega toka pešcev in/ali kolesarjev, nastopajo problemi polnjenja in praznjenja krožnega križišča. Vozila na vhodih/izhodih v krožno križišče morajo pešcem/kolesarjem odstopiti prednost. Vsled tega prihaja do oviranosti tokov in zastojev. V primeru, da do zastojev prihaja na vhodu, vozila ne morejo uvažati v krožno križišče. V primeru, da do zastojev prihaja na izhodu, vozila ne morejo zapuščati krožnega križišča. V primeru, ko je dolžina vozil v koloni tako dolga, da doseže predhodni vhod, prihaja do problemov s polnjenjem krožnega križišča. V prispevku je prikazana metodologija izračuna zmanjšanja kapacitete krožnega križišča zaradi tokov kolesarjev in pešcev. Metodologija izračuna zmanjšanja kapacitete krožnega križišča s pomočjo oviranih tokov je uporabna pri krožnih križiščih v urbanih sredinah, kjer so jakosti prometnih tokov kolesarjev in pešcev nezanemarljive.

Abstract

Interest in Intelligent Transportation Systems comes from the problems caused by traffic congestion, road accidents and air pollution. Traffic congestion continues to grow worldwide as a result of increased motorization, population growth, changes in population density and urbanization. Interest in ITS can also be attributed to reducing road accidents and increasing traffic safety. The most common causes for road accidents are excessive speed, inattentive driving and ignorance of the right-of-way rules. To eliminate these causes, experience, knowledge of traffic regulations and a new car are not enough % vehicle safety systems have to take part as well. Therefore, the European Union issued a directive on the installation of intelligent systems, whose functions are active support during driving, warning the driver in dangerous situations and alerting passengers of the car in case of irregularities in motor function or actions carried out by the driver that may cause danger, such as swerving while falling asleep. These systems help drivers to avoid accidents, and in the event of a collision, an emergency call is automatically made. Furthermore, they can be used to regulate traffic patterns or to reduce engine performance, which would reduce pollution. With these benefits in mind, the EU has indicated to the automotive industry that installation of these new Intelligent Transportation Systems should be mandatory in their new vehicles. Zainteresowanie Inteligentnymi Systemami Transportowymi (ITS) wynika z problemów spowodowanych przeciążeniem ruchu drogowego, wypadkami drogowymi oraz zanieczyszczeniem powietrza. Przeciążenie ruchu stale wzrasta na całym świecie, jako rezultat wzrostu motoryzacyjnego, zwiększenia liczby ludności, zmiany w gęstości zaludnienia oraz urbanizacji. Zainteresowanie ITS może również być przypisane redukcji wypadków oraz zwiększenie bezpieczeństwa na drogach. Najczęstszymi powodami wypadków drogowych są nadmierna prędkość, nieuważne prowadzenie samochodu oraz ignorowanie zasad ruchu drogowego. By wyeliminować te powody, doświadczenie, wiedza o zasadach ruchu drogowego oraz nowy samochód nie są wystarczające – powinny tu również brać udział systemy bezpieczeństwa pojazdu. Dlatego też Unia Europejska ustanowiła dyrektywę o instalowaniu inteligentnych systemów, których funkcje to aktywne wspieranie podczas jazdy, ostrzeganie kierowcy o sytuacjach niebezpiecznych oraz powiadamianie pasażerów samochodu w razie nieprawidłowości w działaniu silnika lub o działaniach powodowanych przez kierowcę, które mogą powodować niebezpieczeństwo, takie jak zbaczanie z drogi w wyniku zasypiania. Systemy te pomagają kierowcom zapobiec wypadkom oraz w razie kolizji wykonują automatycznie telefon alarmowy. Co więcej, mogą być stosowane do regulowania wzorców ruchu lub redukcji osiągów silnika, co zmniejsza ilość zanieczyszczeń. Mając na uwadze te korzyści, Unia Europejska zaleciła przemysłowi motoryzacyjnemu, instalowanie Inteligentnych Systemów Transportowych w nowych pojazdach. Document type: Article

Abstract

The main purpose of this study was to investigate the use of various chaotic pattern recognition methods for traffic flow prediction. Traffic flow is a variable, dynamic and complex system, which is non-linear and unpredictable. The emergence of traffic flow congestion in road traffic is estimated when the traffic load on a specific section of the road in a specific time period is close to exceeding the capacity of the road infrastructure. Under certain conditions, it can be seen in concentrating chaotic traffic flow patterns. The literature review of traffic flow theory and its connection with chaotic features implies that this kind of method has great theoretical and practical value. Researched methods of identifying chaos in traffic flow have shown certain restrictions in their techniques but have suggested guidelines for improving the identification of chaotic parameters in traffic flow. The proposed new method of forecasting congestion in traffic flow uses Wigner-Ville frequency distribution. This method enables the display of a chaotic attractor without the use of reconstruction phase space. Osnovni namen študije je raziskati uporabo metode razpoznavanja kaotičnih vzorcev za uporabo pri napovedovanju zgostitve prometnega toka v cestnem prometu. Prometni tok je spremenljiv, dinamičen in kompleksen sitem, ki je nelinearen nepredvidljiv. Nastanek zgostitve prometnega toka na cestnem odseku ocenjujemo v časovnem intervalu, ko le-ta prične presegati kapaciteto cestnega odseka. Pod določenimi pogojih je mogoče zaznati kaotični vzorec v prometnem toku. Pregled literature teorije prometnega toka in njegovo povezavo s teorijo kaosa je prikazal veliko teoretično in praktično vrednost tovrstne metode. Raziskane metode identifikacije kaotičnega vzorca v prometnem toku so pokazale omejitve, zato je v nadaljevanju opisana smernica za izboljšavo prepoznavanja kaotičnih vzorcev v prometnem toku. Predlagana nova metoda za napovedovanje zgostitev v prometnem toku predlaga uporabo Wigner-Ville frekvenčne porazdelitve. Postopek omogoča prikaz kaotičnega atraktorja brez uporabe rekonstrukcije faznega prostora.