Motorway Tidal Flow Lane Control

A traffic control case of particular importance occurs when inbound and outbound traffic on a motorway stretch is unbalanced throughout the day. This scenario may benefit of a lane management strategy called tidal flow (or reversible) lane control, in which case the direction of a contraflow buffer lane is reversed according to the needs of each direction. This paper proposes a simple and practical real-time strategy for efficient motorway tidal flow lane control. A switching policy based on the fundamental diagram, that requires only aggregated measurements of density (or occupancy), is adopted. A kinematic wave theory-based traffic flow analysis shows that the proposed strategy provides a Pareto-optimal solution. Simulation studies of the A38(M) Aston Expressway (Birmingham, UK), are used to demonstrate its operation. The results confirm an increase of motorway throughput and a smooth operation of the strategy

Optimal Control of Motorway Tidal Flow

When inbound and outbound traffic on a bi-directional motorway is unbalanced throughout the day a lane management strategy called tidal (reversible) flow lane control is usually applied. In this control case, the direction of one or more contraflow buffer lanes is reversed according to the needs of each direction. This paper introduces a basic dynamical model for tidal traffic flow and considers the minimum traveltime, minimum-time, and maximum throughput optimal control problems for efficient motorway tidal flow lane control. Lane management is effectuated by a control variable, indicating the number of lanes opened or closed in each direction of traffic. To derive the analytical form of optimal control, the Pontryagin's maximum principle is employed. The obtained optimal control is intuitively natural of bang-bang type, as also shown in a previous work by the authors [1]. It takes only the values ±1 and switches between these values at most once. In other words, the optimal control strategy consists of switching between opening and closing in each direction of traffic one contraflow buffer lane. Of course it is an open-loop control, and thus the switch time (if applicable) depends on the initial conditions. In the case of the maximum throughput optimal control problem, semi-state feedback control is obtained and singular arcs might exist. Finally, cumulative arrival rate and output curves for both directions of traffic are used to provide a graphical interpretation of the minimum travel-time optimal control problem and obtained bang-bang control

Motorway tidal flow lane control

The expansion of road infrastructure, in spite of increasing congestion levels, faces severe restrictions from all sorts: economical, environmental, social, or technical. An efficient and, usually, less expensive alternative to improve mobility and the use of available infrastructure is the adoption of traffic management. A particular case of interest occurs when inbound and outbound traffic on a given facility is unbalanced throughout the day. This scenario may benefit of a lane management strategy called tidal flow (or reversible) lane control, in which case the direction of one or more contraflow buffer lanes is reversed according to the needs of each direction. This paper proposes a simple and practical real-time strategy for efficient motorway tidal flow lane control. A state-feedback switching policy based on the triangular fundamental diagram, that requires only aggregated measurements of density, is adopted. A theoretical analysis based on the kinematic wave theory shows that the strategy provides a Pareto-optimal solution. Microsimulations using empirical data from the A38(M) Aston Expressway in Birmingham, UK, are used to demonstrate the operation of the proposed strategy. The robustness of the switching policy to parameter variations is demonstrated by parametric sensitivity analysis. Simulation results confirm an increase of motorway throughput and a smooth operation for the simulated scenarios

2nd Symposium on Management of Future motorway and urban Traffic Systems (MFTS 2018): Booklet of abstracts: Ispra, 11-12 June 2018

The Symposium focuses on future traffic management systems, covering the subjects of traffic control, estimation, and modelling of motorway and urban networks, with particular emphasis on the presence of advanced vehicle communication and automation technologies. As connectivity and automation are being progressively introduced in our transport and mobility systems, there is indeed a growing need to understand the implications and opportunities for an enhanced traffic management as well as to identify innovative ways and tools to optimise traffic efficiency. In particular the debate on centralised versus decentralised traffic management in the presence of connected and automated vehicles has started attracting the attention of the research community. In this context, the Symposium provides a remarkable opportunity to share novel ideas and discuss future research directions.JRC.C.4-Sustainable Transpor

Improving Traffic Flow at Long-term Roadworks

AbstractLong-term roadworks on highways are vital as part of carriageway and bridge renovations. They generate bottlenecks and consequently congestion and accidents. If the number of lanes is reduced, it can also lead to significant capacity decrease. Even if it is ensured that all lanes are kept operative, narrow lanes and transitions will affect the capacity. The impact of roadworks on capacity have been analysed in detail by [BECK_2001]. Therefore, intelligent solutions to support the traffic flow at long-term roadworks bottlenecks have to be evaluated. For this purpose the TrafficChange concept was developed. TrafficChange describes the modules of tidal flows on long-term roadworks: - Module 1: Tidal Flow basic set - TrafficChange SE (quickly repositionable moveable safety barriers, so-called Quick-Change Moveable Barriers (QMB)) - Module 2: Attached Traffic Safety Equipment for Tidal Flow - TrafficChange VT including data collection, traffic monitoring, communication, energy supply and displays - Module 3: Repositionable congestion warning systems to safeguard congestion - Module 4: Core system for data analysis, monitoring and managing traffic (TrafficChange Center) as cloud-based service With these components, a dynamic assignment of lanes to higher demanded direction can be reached. Main application fields of TrafficChange are: - Maintenance of bridges - Renewal of road pavement, road surface restoration (entire carriageway) - Tunnel renovation with two-way traffic in the operational tube - Temporarily adaption of the number of operational lanes in dependency of the traffic demand in order to enlarge working space of a roadworks The use of TrafficChange has beneficial effects on capacity and thus on traffic flow. In case of traffic lane reduction due to roadworks, TrafficChange can dynamically assign the remaining traffic lanes according to the demand of both driving directions. Even if all traffic lanes are kept operational during the roadworks, TrafficChange provides several advantages. In case of roadworks on a six lane facility (three lanes in both directions), usually one lane has to be managed separately on the carriageway of the construction field. This has a massive negative impact on the roadworks progress and the completion timetable. When applying TrafficChange this single separate lane is not necessary. Simultaneously this leads to significant capacity increase for this lane, since all lanes are managed on one carriageway and overtaking opportunity is provided. Evaluations of roadworks in Germany have shown that using TrafficChange will enhance the capacity by 10-15% for the driving direction of the construction site. One the other hand, for the direction with low demand, capacity is reduced temporarily, since one lane less is available. When demand for this period is low and can be managed by using the remaining lanes, the traffic flow quality stays efficient. For an economically efficient use of TrafficChange, the demand peaks should not occur simultaneously in both directions. Therefore, for each roadworks it needs to be evaluated individually whether TrafficChange can efficiently improve the traffic flow. For evaluation of the effects, the TrafficChange system is implemented in a microscopic traffic simulation tool, which can be adapted easily for different settings of the roadworks to be evaluated. As input values, the number of available lanes, roadworks design, traffic demand for each required scenario (such as weekday, weekend, holiday) and the length and planned duration of the roadworks are required. As key values, the simulation determines the congestion length, congestion duration and delay times. With these values, the benefit of TrafficChange can be determined. The efficiency estimation is determined by accumulation of total delay times for each required scenario, multiplied by the amount of days this scenario occurs during the roadworks is active, for both the comparison case (roadworks without TC) and target scenario (roadworks with TC). By using current travel time expenses for passenger cars and heavy vehicles, the benefit can be expressed in costs. By the use of TrafficChange, the entire carriageway can be closed so that considerable savings of working period and economic losses could be achieved although the number of operative lanes is lower than in the comparison case. The TrafficChange concept leads to improved traffic safety and optimized traffic flow at roadworks as well as reduced roadworks duration and therefore high economic efficiency that can be determined by the simulation tool TCSim. Literature [BECK_2001] - Beckmann, A., Zackor, H. (2001): Study and calibration of procedures for current estimation of the duration and length of traffic jams as a result of single-day and long-term construction sites on motorways; Forschung Straßenbau und Straßenverkehrstechnik, Volume 808, Bonn, Germany, 2001 [EASY_2009] - Easyway (2009): Mobile Congestion Warning Systems at lorm term roadworks increase traffic safety – Efficiency of Mobile Congestion Warning Systems, Offprint of the ‘Landestelle für Straßentechnik Baden-Württemberg’, Stuttgart, 2009, www.easyway-its.eu [SUEM_2012] - Sümmermann, A. (2012): Examination of traffic safety and traffic flow in work zones on German Motorways, Aachener Mitteilungen Straßenwesen, Erd- und Tunnelbau, Volume 59, Aachen 2012 [VOLK_2014] - Volkenhoff, T. (2014): Model-based derivation of operating conditions of a video-aided incident and work zone management system in construction sites on German motorways, Aachener Mitteilungen Straßenwesen, Erd- und Tunnelbau, Volume 61, Aachen 2014 [HMSV_2012] – HMSV (2012): Congestion Evaluation 2011. Hessen Mobil – Straßen- und Verkehrsmanagement. URL: http://www.staufreieshessen2015.de, requested on 04.07.201

Risk prioritisation of stormwater pollutant sources

This paper describes the development of a pollutant risk prioritisation methodology for the comparative assessment of stormwater pollutants discharged from differing land use types and activities. Guidelines are presented which evaluate available data with respect to ‘likelihood of occurrence’ and ‘severity of impact’. The use of the developed approach is demonstrated through its application to total suspended solids, biochemical oxygen demand, lead and cadmium. The proposed benchmarking scheme represents a transparent and auditable mechanism to support the synthesis of data from a variety of sources and is sufficiently flexible to incorporate the use of chemical, physical and/or ecological data sets. Practitioners involved in developing and implementing pollutant mitigation programmes are assisted in two key ways. Firstly through enabling the risks to receiving waters from diffuse pollution on a source-by-source and/or pollutant-by-pollutant basis at a catchment scale to be comparatively assessed and prioritised. Secondly, the methodology informs the selection of appropriate diffuse pollution control strategies

Risk prioritisation of stormwater pollutant sources

This paper describes the development of a pollutant risk prioritisation methodology for the comparative assessment of stormwater pollutants discharged from differing land use types and activities. Guidelines are presented which evaluate available data with respect to ‘likelihood of occurrence’ and ‘severity of impact’. The use of the developed approach is demonstrated through its application to total suspended solids, biochemical oxygen demand, lead and cadmium. The proposed benchmarking scheme represents a transparent and auditable mechanism to support the synthesis of data from a variety of sources and is sufficiently flexible to incorporate the use of chemical, physical and/or ecological data sets. Practitioners involved in developing and implementing pollutant mitigation programmes are assisted in two key ways. Firstly through enabling the risks to receiving waters from diffuse pollution on a source-by-source and/or pollutant-by-pollutant basis at a catchment scale to be comparatively assessed and prioritised. Secondly, the methodology informs the selection of appropriate diffuse pollution control strategies

Comercio marítimo. Comparativa entre los puertos de España y Bélgica

Maritime trade represents over 80% of global trade. This increasing trend has led to higher collection, storage, and distribution needs. On occasions, it has caused jamming of goods in some ports. This is the reason why the importance of maritime trade is highlighted. The main objective of this Final Degree Project is to find points of improvement in Spanish ports. For this purpose, a comparative study is made between the main Spanish and Belgian ports. The comparison has been carried out through a SWOT analysis that can contribute to improving the competitiveness of our ports.El comercio marítimo representa más del 80% del comercio mundial. Esta tendencia creciente ha provocado un aumento de las necesidades de recogida, almacenamiento y distribución, provocando en ocasiones atascos de mercancías en algunos puertos. Es por ello que se resalta la importancia del comercio marítimo a nivel mundial. El objetivo principal de este Trabajo de Fin de Grado es encontrar puntos de mejora en los puertos españoles. Para ello, se elabora un estudio comparativo entre los principales puertos españoles y los principales puertos belgas. La comparativa se ha llevado a cabo a través de un análisis DAFO que pueda contribuir a mejorar la competitividad de nuestros puertos.<br /