Effectiveness of the Two-Step Dynamic Demand Estimation model on large networks

in Proceedings of 2017 5th IEEE International Conference on Models and Technologies for Intelligent Transportation Systems (MT-ITS) (2017, June 28)

In this paper, the authors present a Two-Step approach that sequentially adjusts generation and distribution values of the (dynamic) OD matrix. While the proposed methodology already provided excellent ... [more ▼]

In this paper, the authors present a Two-Step approach that sequentially adjusts generation and distribution values of the (dynamic) OD matrix. While the proposed methodology already provided excellent results for updating demand flows on a motorway, the aim of this paper is to validate this conclusion on a real network: Luxembourg City. This network represents the typical middle-sized European city in terms of network dimension. Moreover, Luxembourg City has the typical structure of a metropolitan area, composed of a city centre, ring, and suburb areas. An innovative element of this paper is to use mobile network data to create a time-dependent profile of the generated demand inside and outside the ring. To support the claim that the model is ready for practical implementation, it is interfaced with PTV Visum, one of the most widely adopted software tools for traffic analysis. Results of these experiments provide a solid empirical ground in order to further develop this model and to understand if its assumptions hold for urban scenarios. [less ▲]

Lessons learnt from a corporate car-sharing system: the case of the University of Luxembourg

Scientific Conference (2017, May)

Discussion on cross-border integration using non-dominant mobility flows

Scientific Conference (2017, April 12)

On the edge of two different countries, cross-border regions exhibit very peculiar features. While borders can be seen as an interface or a barrier, analyze the interactions between two sovereign spatial ... [more ▼]

On the edge of two different countries, cross-border regions exhibit very peculiar features. While borders can be seen as an interface or a barrier, analyze the interactions between two sovereign spatial entities is extremely important for political reasons, economical development, land use management, etc. Because of data availability issues, spatial cross-border integration is mostly characterized using cross-border workers commuting flow information, or more rarely, by using activities performed by cross-border workers in the country they work. Despite its small size (2586 km2), the Grand-duchy of Luxembourg is a strong economic locomotive. Among the 380 000 available jobs in the country, 42% are occupied by cross border workers from France, Belgium and Germany. While the commuting behavior and the activity chains of the cross border workers have been largely studied this is not the case for the population living in Luxembourg. This study, using two weeks of travel diary data of 35 staff members of the University of Luxembourg living in the Grand-Duchy of Luxembourg, aims at analyzing the relationship that the respondents have with borders. Our hypothesis is that cross-border integration characterization would gain in robustness if non-dominant centripetal flows were taken into account as well. [less ▲]

Usage of Smartphone Data to Derive an Indicator for Collaborative Mobility between Individuals

in ISPRS International Journal of Geo-Information (2017), 6(3), 62

The potential of geospatial big data has been drawing attention for a few years. Despite the larger and larger market penetration of portable technologies (nomadic and wearable devices like smartphones ... [more ▼]

The potential of geospatial big data has been drawing attention for a few years. Despite the larger and larger market penetration of portable technologies (nomadic and wearable devices like smartphones and smartwatches), their opportunities for travel behavior analysis are still relatively unexplored. The main objective of our study is to extract the human mobility patterns from GPS traces in order to derive an indicator for enhancing Collaborative Mobility (CM) between individuals. The first step, extracting activity duration and location, is done using state-of-the-art automated recognition tools. Sensors data are used to reconstruct individual’s activity location and duration across time. For constructing the indicator, in a second step, we defined different variables and methods for specific case studies. Smartphone sensor data are being collected from a limited number of individuals and for one week. These data are used to evaluate the proposed indicator. Based on the value of the indicator, we analyzed the potential for identifying CM among groups of users, such as sharing traveling resources (e.g., carpooling, ridesharing, parking sharing) and time (rescheduling and reordering activities). [less ▲]

Experimental analysis of eGLOSA and eGLODTA transit control strategies

in Proceedings of the 5th IEEE International Conference on Models and Technologies for Intelligent Transportation Systems, MT-ITS 2017 (2017)

Battery powered electric buses have higher energy efficiency, lower emissions and noise when compared to buses with internal combustion engines. However, due to battery charging requirements, their large ... [more ▼]

Battery powered electric buses have higher energy efficiency, lower emissions and noise when compared to buses with internal combustion engines. However, due to battery charging requirements, their large-scale integration into public transport operations is more complex. This study proposes a novel concept supporting said integration via new control strategies, dubbed e-GLOSA and e-GLODTA. These strategies extend the existing Green Light Optimal Speed and Dwell Time Systems (GLOSA/GLODTA) to account for the specific needs of electric buses. That is, they include the goals of minimizing the energy consumption between charging stations, and maximizing available charging time. At the same time, interference with schedule requirements is minimized. The formulated heuristics are tested on a Bus Rapid Transit (BRT) corridor case study, where different scenarios—such as placement of charging stations and bus regularity—are studied to assess under which conditions each action (maintain speed, accelerate or dwell for a longer time at a stop) is beneficial. Results show that eGLOSA contributes to schedule adherence while eGLODTA allows satisfying charging time constraints. [less ▲]

Exact and approximate route set generation for resilient partial observability in sensor location problems

in Transportation Research. Part B : Methodological (2017), 105

Sensor positioning is a fundamental problem in transportation networks, as the location of sensors strongly determines how traffic flows are observable and hence manageable. This paper aims to develop a ... [more ▼]

Sensor positioning is a fundamental problem in transportation networks, as the location of sensors strongly determines how traffic flows are observable and hence manageable. This paper aims to develop a methodology to determine sensor locations on a network such that an optimal trade-off solution is found between the amount of sensors installed and the resilience of the sensor set. In particular, we propose exact and heuristic solutions for identifying the optimal route sets such that no other route would include any additional information for finding optimal full and partial observability solutions. This is an important contribution to sensor location problems, as route-based link flow inference problems have non-unique solutions, strongly depending on the used link-route information. The properties of the new methodology are analyzed and illustrated through different case studies, and the advantages of the algorithms are quantified both for full and for partial observability solutions. Due to the route sets found by our approach, we are able to find full observability solutions characterized by a small number of sensors, while yet being efficient also in terms of partial observability. We perform validation tests on both small and real-life sized network instances. © 2017 Elsevier Ltd [less ▲]

An iterative learning approach for anticipatory traffic signal control on urban networks

in Transportmetrica B: Transport Dynamics (2017), 5(4), 407-430

On characterizing the relationship between route choice behavior and optimal traffic control solution space

in Transportation Research Procedia (2017), 23

Explicitly including the dynamics of users' route choice behaviour in optimal traffic control applications has been of interest for researchers in the last five decades. This has been recognized as a very ... [more ▼]

Explicitly including the dynamics of users' route choice behaviour in optimal traffic control applications has been of interest for researchers in the last five decades. This has been recognized as a very challenging problem, due to the added layer of complexity and the considerable non-convexity of the resulting problem, even when dealing with simple static assignment and analytical link cost functions. In this work we establish a direct behavioural connection between the different shapes and structures emerging in the solution space of such problems and the underlying route choice behaviour. We specifically investigate how changes in the active equilibrium route set exert direct influence on the solution space's structure and behaviour. Based on this result, we then formulate and validate a constrained version of the original problem, yielding desirable properties in terms of solution space regularity. © 2017 The Authors. [less ▲]

A local dynamic route and green time swapping control algorithm maximizing total network capacity

in Proceedings of the 25th Mediterranean Conference on Control and Automation, MED 2017 (2017)

This paper deals with the traffic signal control problem. More specifically it investigates the impact at a network level of simple dynamic local traffic control policies. A dynamic route swapping rule is ... [more ▼]

This paper deals with the traffic signal control problem. More specifically it investigates the impact at a network level of simple dynamic local traffic control policies. A dynamic route swapping rule is adopted to model the behavioral response of the travellers to signal changes, while a dynamic signal control swapping rule based on an equi-pressure policy is used to implicitly consider the flow response within the control updating process. Results on a simple network show that the flow responsive control policy outperforms pre-timed control, as well as a more conventional local control policy based on signal equi-saturation. Numerical results show also that the swapping rule based on equi-pressure is less susceptible to local optima, to systematically improve total network throughput, and to increase its effectiveness with when demand increases. © 2017 IEEE. [less ▲]

A real-time holding decision rule accounting for passenger travel cost

Scientific Conference (2016, November 04)

Holding has been extensively investigated as a strategy to mitigate the inherently stochastic nature of public transport operations. Holding focuses on either regulating vehicle headways using a rule ... [more ▼]

Holding has been extensively investigated as a strategy to mitigate the inherently stochastic nature of public transport operations. Holding focuses on either regulating vehicle headways using a rule-based approach or minimizing passenger travel cost by employing optimization models. This paper introduces a holding decision rule that explicitly addresses passenger travel cost. The decision to hold relies on the passenger demand distribution along the line. The passenger cost holding rule is tested using simulation for a high frequency bus line in Stockholm, Sweden and is compared with a nocontrol scheme and the currently used headway-based strategy. The results indicate that the new decision rule results in relatively minor reductions of passenger cost compared to the currently adopted strategy, and that it allocates the greatest share of holding time at the beginning of the route. [less ▲]