Abstract

"jats:p" The transport sector represents a vital component of national economies and has significant impacts on productivity and social welfare. In 2012, the transport sector in Europe was estimated to account for 3.7% of the European Gross Domestic Product (GDP) and 5.1% for employment. Road transport proves to be the predominant mode for moving goods within Europe holding a share of approximately 45.8% in 2012 (in ton-kms). In Greece, the share of road freight transport is significantly higher (98%) indicating the importance of this sector for the Greek economy. To this end and considering the existing needs of road freight transport operators in Greece, the objective of this research is to establish an analytical and documented basis for estimating the operating cost of a truck on specific urban or national freight transport routes. To achieve this goal, an extended literature review has been conducted resulting in the identification of the main components comprising the total truck operating cost, which were then updated and validated through a series of personal interviews with selected road freight transport professionals. An excel-based application tool was also developed in order to facilitate operating cost estimates for different cases, through selection of the proper values of the relevant parameters. The resulting tool was used to analyse four test cases, which demonstrate the tool’s usability and applicability. Results from this analysis have been also validated by industry experts and they reflect real-world transport scenarios. Document type: Article

Abstract

network-wide coordination system for heavy-duty vehicle platooning with the purpose of reducing fuel consumption is developed. Road freight is by far the dominating mode for overland transport with over 60 % modal share in the OECD countries and is thus critically important for the economy. Overcoming its strong dependency on fossil fuels and manual labor as well as handling rising congestion levels are therefore important societal challenges. Heavy-duty vehicle platooning is a promising near-term automated-driving technology. It combines vehicle-to-vehicle communication and on-board automation to slipstream in a safe manner, which can reduce fuel consumption by more than 10 %. However, in order to realize these benefits in practice, a strategy is needed to form platoons in an operational context. We propose a platoon coordination system that supports the process of automatically forming platoons over large geographic areas. We develop an architecture in which fleet management systems send start locations, destinations, and arrival deadlines to a platoon coordinator. By computing desirable speed profiles and by letting the vehicles' on-board systems track them, vehicles can meet en route and form platoons. Matching vehicles into platoons and deriving suitable speed profiles is treated as an optimization problem with the objective of maximizing the overall fuel savings under the constraint that vehicles arrive in time at their destinations. By updating the speed profiles and the platoon configurations based on real-time measurements of vehicle position and platoon state, the system can accommodate new vehicles joining on the fly. Using real-time measurements also makes the system resilient to disturbances and changing operating conditions. This thesis seeks to develop the theoretical foundations of such a system and evaluate its potential to improve transport efficiency.   We first explore the coordination of vehicle pairs. Fuel-optimal speed profiles are derived. The uncertainty arising from traffic is taken into account by modeling travel time distributions and considering the probability of two vehicles successfully merging. Building on this coordination algorithm for vehicle pairs, we derive algorithms for larger platoons and vehicle fleets. This results in an NP-hard combinatorial optimization problem. The problem is formulated as an integer program and results on the solution structure are derived. In order to handle realistic fleet sizes with thousands of vehicles and continental sized geographical areas under real-time operation, heuristic algorithms are developed. The speed profiles resulting from the combinatorial optimization are further improved using convex optimization. Moreover, we derive efficient algorithms to identify all pairs of vehicles that can platoon. Simulations demonstrate that the proposed algorithm is able to compute plans for thousands of vehicles. Coordinating approximately a tenth of Germany's heavy-duty vehicle traffic, platooning rates over 65 % can be achieved and fuel consumption can be reduced by over 5 %. The proposed system was implemented in a demonstrator system. This demonstrator system has been used in experiments on public roads that show the technical feasibility of en route platoon coordination. Ett nätverksomfattande system för att koordinera körning i lastbilskolonner i syfte att minska bränsleförbrukningen utvecklas i denna avhandling.Vägtransport är med marginal det mest dominerande sättet för landtransport med en andel över 60 % i OECD-länderna och är således avgörande för samhällsekonomin. Dess starka beroende av fossila bränslen och arbetskraft samt ökande trängsel är därför viktiga utmaningar för samhället. Vägtransport är på väg att genomgå grundläggande förändringar genom elektrifiering, kommunikation och automation. Lastbilskolonnkörning är en teknologi för att automatisera fordon, som är redo att lanseras inom en snar framtid. Kolonnkörning kan ge bränslebesparingar på över 10 % tack vare att automatisering och kommunikation mellan fordon möjliggör så kallad slipstreaming på ett säkert sätt. Det behövs dock en strategi för att sätta ihop lastbilskolonner för att kunna dra nytta av denna teknologi. Vi föreslår därför ett automatiserat koordineringssystem som stödjer processen att sätta ihop lastbilskolonner inom stora geografiska områden. Vi utvecklar en arkitektur där fleet management system skickar start- och målpunkter samt senaste ankomsttid till koordineringssystemet. Genom att beräkna passande hastighetsprofiler och genom att låta lastbilarnas färddatorer följa dem kan lastbilar mötas på vägen och bygga ihop kolonner. Problemet att matcha fordon till kolonner och att komma fram till passande hastighetsprofiler hanteras som ett optimeringsproblem med målet att maximera den totala bränslebesparingen. Genom att uppdatera lösningen baserade på realtidsmätningar av fordonspositioner och kolonntillstånd kan systemet hantera tillkommande lastbilar och kan vara robust gentemot störningar och förändrade operativa förutsättningar. Denna avhandling strävar efter att utveckla teoretiska förutsättningar för ett sådant system och att utvärdera dess potential att öka transportsystemets effektivitet. Vi börjar med att undersöka koordinering av fordonspar och härleder bränsleoptimala hastighetsprofiler. Den osäkerhet som beror på trafiken tas hänsyn till genom att modellera hastighetsfördelningar och genom att betrakta sannolikheten att två fordon träffas och kan påbörja kolonnkörning. Vi bygger på denna algoritm för fordonspar för att härleda algoritmer som kan hantera större kolonner och större antal lastbilar. Det resulterar i ett NP-svårt kombinatoriskt optimeringsproblem. Problemet formuleras som ett heltalsoptimieringsproblem och vi kommer fram till resultat som visar strukturen av lösningen. Resulterande hastighetsprofiler förbättras ytterligare med hjälp av konvex optimering. Förutom detta utvecklas effektiva algoritmer för att identifiera alla fordonspar som kan köra i kolonn. Simuleringar demonstrerar att den föreslagna algoritmen klarar att beräkna planer för tusentals lastbilar. Vi visar att en samording av c:a 10 % av Tysklands lastbilstrafik kan tillåta att mer än 65 % av den totala körsträckan körs i kolonn och att bränsleåtgången kan minskas med mer än 5 %. Det presenterade systemet implementerades i ett demonstratorsystem. Experiment med demonstratorn på allmän väg har visat att koordinering av kolonnkörning på vägen är tekniskt genomförbart. "p"QC 20180403

Abstract

Road freight transport is responsible for about one-third of road transport emissions and it is still growing. One solution to decarbonize this sector are electric trolley trucks powered by overhead lines. We compare electric trolley trucks to conventional diesel vehicles from a techno-economic perspective in Germany up to 2030. We find that an infrastructure set-up ordered by utilization of roads can be financed up to 2700 km with higher savings than cost. The impact on the energy system is lower than expected and the largest impacts are found in rural areas with highway intersections. Further fields of research are discussed. Document type: Article

Abstract

Finnish government allowed in October 2013 operating high capacity vehicles (HCV) with a maximum weight limit of 76 t on Finnish roads. An analysis on how HCVs have affected the Finnish road freight transport sector is presented here based on a continuous time series data from 2013 to 2017. The analysis shows a significant increase in the average payload weight and a transition from 7-axle to 8- and 9-axle articulated vehicle combinations, which allow the higher weights. Truck mileage of 225 million km has been avoided from October 2013 until the end of 2017 and avoided mileage corresponded in 2017 to approximately 4% of total truck mileage in Finland. This equals around 126 million € cost savings in 2017 and 0.1 Mt of CO2 emissions reduction in road freight, even after taking into account that there has been some modal shift from rail to road. Document type: Article