ICT Infrastructure for Cooperative, Connected and Automated Transport in Transition Areas

One of the challenges of automated road transport is to manage the coexistence of conventional and highly automated vehicles, in order to ensure an uninterrupted level of safety and efficiency. Vehicles driving at a higher automation level may have to change to a lower level of automation in a certain area under certain circumstances and certain (e.g. road and weather) conditions. The paper targets the transition phases between different levels of automation. It will review related research, introduce a concept to investigate automation level changes, present some recent research results, i.e. assessing key performance indicators for both analysing driver behaviour and traffic management in light of autonomous vehicles, an initial simulation architecture, and address further research topics on investigation of the traffic management in such areas (called "Transition Areas") when the automation level changes, and development of traffic management procedures and protocols to enable smooth coexistence of automated, cooperative, connected vehicles and conventional vehicles, especially in an urban environment

Data-driven Methods for Identifying Travel Conditions Based on Traffic and Weather Characteristics

Accurate and reliable traffic state estimation is essential for the identification of congested areas and bottleneck locations. It enables the quantification of congestion characteristics, such as intensity, duration, reliability, and spreading which are indispensable for the deployment of appropriate traffic management plans that can efficiently ameliorate congestion problems. Similarly, it is important to categorize known congestion patterns throughout a long period of time, so that corresponding traffic simulation models can be built for the investigation of the performance of different traffic management plans. This study conducts cluster analysis to identify days with similar travel conditions and congestion patterns. To this end, travel, traffic and weather data from the Smart Mobility Living Lab of Thessaloniki, Greece is used. Representative days per cluster are determined to facilitate the development of traffic simulation models that typify average traffic conditions within each cluster. Moreover, spatio-temporal matrices are developed to illustrate time-varying traffic conditions along different routes for the representative days. Results indicate that the proposed clustering technique can produce valid classification of days in groups with common characteristics, and that spatio-temporal matrices enable the development of traffic management plans which encompass routing information for competing routes in the city of Thessaloniki

Reinforcement Learning-based Traffic Control: Mitigating the Adverse Impacts of Control Transitions

An important aspect of automated driving is to handle situations where it fails or is not allowed in specific traffic situations. This case study explores means, by which control transitions in a mixed autonomy system can be organized in order to minimize their adverse impact on traffic flow. We assess a number of different approaches for a coordinated management of transitions, covering classic traffic management paradigms and AI-driven controls. We demonstrate that they yield excellent results when compared to a do-nothing scenario. This text further details a model for control transitions that is the basis for the simulation study presented. The results encourage the deployment of reinforcement learning on the control problem for a scenario with mandatory take-over requests

Enhanced Traffic Management Procedures of Connected and Autonomous Vehicles in Transition Areas

In light of the increasing trend towards vehicle connectivity and automation, there will be areas and situations on the roads where high automation can be granted, and others where it is not allowed or not possible. These are termed ‘Transition Areas’. Without proper traffic management, such areas may lead to vehicles issuing take-over requests (TORs), which in turn can trigger transitions of control (ToCs), or even minimum-risk manoeuvres (MRMs). In this respect, the TransAID Horizon 2020 project develops and demonstrates traffic management procedures and protocols to enable smooth coexistence of automated, connected, andconventional vehicles, with the goal of avoiding ToCs and MRMs, or at least postponing/accommodating them. Our simulations confirmed that proper traffic management, taking the traffic mix into account, can prevent drops in traffic efficiency, which in turn leads to a more performant, safer, and cleaner traffic system, when taking the capabilities of connected and autonomous vehicles into account

TransAID Deliverable 6.2/2 - Assessment of Traffic Management Procedures in Transition Areas

This Deliverable 6.2 of the TransAID project presents and evaluates the simulation results obtained for the scenarios considered during the project's first and second iterations. To this end, driver- and AV-models designed in WP3, traffic management procedures developed in WP4, and V2X communication protocols and models from WP5 were implemented within the iTETRIS simulation framework. Previous main results from Deliverable 4.2, where baseline and traffic management measures without V2X communication were compared, have been confirmed. While not all TransAID scenarios' traffic KPIs were affected, the realistic simulation of V2X communication has shown a discernible impact on some of them, which makes it an indispensable modelling aspect for a realistic performance evaluation of V2X traffic scenarios. Flaws of the first iteration's traffic management algorithms concerning wireless V2X communication and the accompanying possibility of packet loss were identified and have been addressed during the project's second iteration. Finally, lessons learned while working on these simulation results and assessments have additionally been described in the form of recommendations for the real-world prototype to be developed in WP7. We conclude that all results obtained for all scenarios when employing ideal communication confirmed the statistical trends of the results from the original TM scenarios as reported in Deliverable 4.2 where no V2X communication was considered. Furthermore, the performance evaluation of the considered scenarios and parameter combinations has shown the following, which held true in both the first and second iterations: (1) The realistic simulation of V2X communication has an impact on traffic scenarios, which makes them indispensable for a realistic performance evaluation of V2X traffic scenarios. (2) Traffic management algorithms need to account for sporadic packet loss of various message types in some way. (3) Although important, the realistic modelling and simulation of V2X communication also induces a significant computational overhead. Thus, from a general perspective, a trade-off between computation time and degree of realism should be considered

Assessment of ACC and CACC systems using SUMO

Emerging developments in the field of automotive technologies, such as Adaptive Cruise Control (ACC) and Cooperative Adaptive Cruise Control (CACC) systems, are expected to enhance traffic efficiency and safety on highways and urban roads. For this reason, substantial effort has been made by researchers to model and simulate these automation systems over the last few years. This study aims to integrate a recently developed car-following model for ACC and CACC equipped vehicles in the microscopic traffic simulation tool SUMO; the implemented ACC/CACC simulation models originate from empirical ones, ensuring the collision-free property in the full-speed-range operation. Simulation experiments for different penetration rates of cooperative automated vehicles, desired time-gap settings and network topologies are conducted to test the validity of the proposed approach and to assess the impact of ACC and CACC equipped vehicles on traffic flow characteristics

Μαθηματικά πρότυπα δυναμικής οικολογικής οδήγησης σε σηματοδοτούμενες αρτηρίες στο πλαίσιο συνεργατικών ευφυών συστημάτων μεταφορών

This PhD dissertation enhances the human-centered design of existing dynamic eco-driving systems, and models driver adaptation to energy-efficient speed advice upstream of signalized intersections with the use of decision trees and empirical evidence generated via the pilot operation of an advisory dynamic eco-driving system along an urban arterial corridor, quantifies the relevant impacts on emissions, and compares them with the case of automated execution of dynamic eco-driving advice. Moreover, it proposes a simulation framework that is comprised of a microscopic traffic simulator, an external test-bed for emulating dynamic eco-driving, multiple tools for the analysis of simulation output, and a comprehensive set of simulation scenarios for evaluating the performance of different variants of dynamic eco-driving technology.Results indicate that despite rendering advised deceleration strategies more conservative for enhancing user acceptance and safety, traffic and energy efficiency of dynamic eco-driving are not undermined. Moreover, advisory dynamic eco-driving can yield significant emissions reduction compared to unequipped manually driven vehicles for increased market penetration rate of the relevant technology. However, for multi-vehicle and multi-lane traffic simulation experiments environmental, traffic and safety benefits are maximized when dynamic eco-driving is automated and market penetration rate is maximum. Finally, the implications of this PhD dissertation’s results with respect to system design, operational, technological and policy aspects of dynamic eco-driving are discussed.Η παρούσα διδακτορική διατριβή αναπτύσσει μεθόδους που βελτιώνουν τον ανθρωποκεντρικό σχεδιασμό των συστημάτων περιβαλλοντικά φιλικής οδήγησης, προτυποποιούν την προσαρμογή των οδηγών σε ενεργειακά αποδοτικές στρατηγικές οδήγησης ανάντη σηματοδοτημένων διασταυρώσεων με τη χρήση δένδρων αποφάσεων και εμπειρικών δεδομένων που συλλέχθηκαν κατά την πιλοτική εφαρμογή ενός συστήματος περιβαλλοντικά φιλικής οδήγησης κατά μήκος μιας αστικής οδικής αρτηρίας, ποσοτικοποιούν τις συναφείς περιβαλλοντικές και κυκλοφοριακές επιπτώσεις, καθώς και καθιστούν εφικτή τη σύγκριση επιδόσεων με αυτοματοποιημένα συστήματα περιβαλλοντικά φιλικής οδήγησης, όπου το όχημα είναι ταυτοχρόνως εξοπλισμένο με συστήματα αυτοματοποιημένης οδήγησης που επιτρέπουν την ακριβή προσαρμογή σε ενεργειακά αποδοτικά προφίλ ταχυτήτων. Επιπλέον, η αξιολόγηση επιπτώσεων των συστημάτων περιβαλλοντικά φιλικής οδήγησης γίνεται μέσω της ανάπτυξης λογισμικού που προσομοιώνει τη λειτουργία τους στα πλαίσια μοντέλου μικροσκοπικής προσομοίωσης της κυκλοφορίας για διαφορετικές συνθήκες ζήτησης μετακινήσεων αλλά και διείσδυσης της συγκεκριμένης τεχνολογίας στο συνολικό στόλο των οχημάτων.Τα αποτελέσματα των αναλύσεων της μικροσκοπικής προσομοίωσης της κυκλοφορίας κατέδειξαν ότι οι προσαρμογές στη δομή των υφιστάμενων μοντέλων περιβαλλοντικά φιλικής οδήγησης που αποσκοπούν στην βελτίωση της αποδοχής τους από τους χρήστες αλλά και στην βελτίωση της οδικής ασφάλειας δεν επηρεάζουν αρνητικά την απόδοσή τους αναφορικά με τη μείωση της ενεργειακής κατανάλωσης και των εκπομπών αέριων ρύπων. Επίσης, το περιβαλλοντικό αποτύπωμα διασυνδεδεμένων οχημάτων που είναι εξοπλισμένα με συμβουλευτικού τύπου συστήματα περιβαλλοντικά φιλικής οδήγησης είναι σημαντικά μικρότερο σε σχέση με συμβατικά οχήματα όταν το ποσοστό διείσδυσης στο στόλο των παραπάνω συστημάτων είναι υψηλό. Είναι όμως αξιοσημείωτο, ότι σε οδικές αρτηρίες πολλαπλών λωρίδων η μεγιστοποίηση των περιβαλλοντικών και κυκλοφοριακών πλεονεκτημάτων των συστημάτων περιβαλλοντικά φιλικής οδήγησης συμβαίνει όταν αυτά είναι αυτοματοποιημένου τύπου και η διείσδυσή τους στο στόλο είναι μέγιστη. Τελικώς, αναλύονται οι επιπτώσεις των ευρημάτων της συγκεκριμένης διδακτορικής διατριβής αναφορικά με τον ανθρωποκεντρικό σχεδιασμό των συστημάτων περιβαλλοντικής οδήγησης συμβουλευτικού τύπου και τη ορθή εφαρμογή τους σε πραγματικές κυκλοφοριακές συνθήκες

The use of a transport simulation system (AIMSUN) to determine the environmental effects of pedestrianization and traffic management in the center of Thessaloniki

Traffic congestion in urban areas results in increased energy consumption and vehicle emissions. Traffic management that alleviates traffic congestion also mitigates the environmental effects of vehicular traffic. This study uses the transport simulation model AIMSUN to evaluate the environmental effect of a set of traffic management and pedestrianization schemes. The effects of the pedestrianization of specific sections of roads, converting two-way roads into one-way roads for traffic and changing the direction of flow of traffic along one-way roads were simulated for different areas of Thessaloniki’s city centre network. The assessment of the environmental effect was done by determining the predicted fuel consumption and emissions of greenhouse gases (GHG) and air pollutants. Fuel consumption and the environmental indicators were quantified directly using the fuel consumption and emissions model in AIMSUN. A typical weekday morning peak period, between 09:00am–10:00am, was simulated and the demand data obtained using a macroscopic traffic assignment model previously developed for the wider area of Thessaloniki. The results presented in this paper are for network-wide simulation statistics (i.e. fuel consumed, carbon dioxide (CO2), nitrogen oxides (NOx) and particulate matter (PM))

Intelligent transport systems deployment in Thessaloniki: Assessment of costs and benefits

Transportation projects often require large initial investments and are expected to generate benefits extending far into the future. Thus, there is a need to compare benefits and costs that occur at different periods over time. Since money has a time value, the same amount of money at different time periods does not have the same value. Therefore, it is important to convert costs and benefits into equivalent values when conducting a Cost-Benefit Analysis (CBA). A special category of transportation projects is that of Intelligent Transport Systems (ITS). ITS comprise innovative solutions for travel demand and traffic management, and it is expected to play a key role in future sustainable urban development plans. Compared to other transportation projects, ITS have a lower initial investment. In this paper a framework based on a CBA is presented, assessing costs and benefits of three ITS projects implemented in Thessaloniki, Greece. The paper refers to future developments of ITS in the city of Thessaloniki. The examined systems have already been developed as demonstration systems in various regions throughout Europe. The benefits of the systems have been transferred and scaled up, so as to be in line with the specific characteristics of the Greek environment