A holding control strategy for diverging bus lines

Scientific Conference (2018, July 24)

We introduce a holding criterion for network configurations with lines that operate jointly along a common corridor and then individually diverge. The proposed holding decision rule accounts for all ... [more ▼]

We introduce a holding criterion for network configurations with lines that operate jointly along a common corridor and then individually diverge. The proposed holding decision rule accounts for all different passengers groups in the overlapping segment and takes care of the transition to individual line operation. The holding rule is evaluated using simulation for different demand levels and segmentations and compared with other control schemes for a real-world network. Results show that gains in overall network performance as well as for specific passenger groups can be achieved under specific demand distributions. [less ▲]

Towards Optimised Deployment of Electric Bus Systems with On-Route Charging using Cooperative ITS

Scientific Conference (2018, July)

Improving Public Transport Service Regularity using Cooperative Driver Advisory Systems

Presentation (2018, June 12)

A New Modelling Framework over Temporal Graphs for Collaborative Mobility Recommendation Systems

in A New Modelling Framework over Temporal Graphs for Collaborative Mobility Recommendation Systems (2018, March 15)

Over the years, collaborative mobility proved to be an important but challenging component of the smart cities paradigm. One of the biggest challenges in the smart mobility domain is the use of data ... [more ▼]

Over the years, collaborative mobility proved to be an important but challenging component of the smart cities paradigm. One of the biggest challenges in the smart mobility domain is the use of data science as an enabler for the implementation of large scale transportation sharing solutions. In particular, the next generation of Intelligent Transportation Systems (ITS) requires the combination of artificial intelligence and discrete simulations when exploring the effects of whatif decisions in complex scenarios with millions of users. In this paper, we address this challenge by presenting an innovative data modelling framework that can be used for ITS related problems. We demonstrate that the use of graphs and time series in multi-dimensional data models can satisfy the requirements of descriptive and predictive analytics in real-world case studies with massive amounts of continuously changing data. The features of the framework are explained in a case study of a complex collaborative mobility system that combines carpooling, carsharing and shared parking. The performance of the framework is tested with a large-scale dataset, performing machine learning tasks and interactive realtime data visualization. The outcome is a fast, efficient and complete architecture that can be easily deployed, tested and used for research as well in an industrial environment. [less ▲]

Vulnerability analysis of network observability in link flow inference problems

Scientific Conference (2018, January)

The effect of workplace relocation on individuals’ activity travel behavior

in Journal of Transport and Land Use (2018), 11(1),

On working days, homes and workplaces can be seen as anchor locations at the heart of daily mobility patterns, as well as being central to an employee’s activity pattern. In this study, we investigate how ... [more ▼]

On working days, homes and workplaces can be seen as anchor locations at the heart of daily mobility patterns, as well as being central to an employee’s activity pattern. In this study, we investigate how workplace relocation affects the entire daily activity-travel chain. While past research has shown that workplace decentralization is often associated with higher car use for the commuting trip, little is known about the effect on the whole activity travel pattern. Two waves of a two-week travel diary were completed by 43 employees of the University of Luxembourg: one before and one after the relocation of their office. Using descriptive statistics as well as standard deviational ellipses (SDE) theory combined with the results of a clustering analysis showed that workers’ activity spaces (represented by the standard deviational ellipses) were significantly modified due to the relocation of a single anchor activity location, i.e., their workplace. [less ▲]

Utility-Based Kalman Filtering for real-time estimation of daily demand flows

Scientific Conference (2018)

Time-dependent Origin-Destination (OD) demand flows are fundamental inputs for Dynamic Traffic Assignment (DTA) systems and real-time traffic management. This work introduces a novel state-space framework ... [more ▼]

Time-dependent Origin-Destination (OD) demand flows are fundamental inputs for Dynamic Traffic Assignment (DTA) systems and real-time traffic management. This work introduces a novel state-space framework to estimate these demand flows in an online context. Specifically, we propose to explicitly include trip-chaining behavior within the state-space formulation, which is solved using the well-established Kalman Filtering technique. While existing works already consider structural information and recursive behavior within the online demand estimation problem, this information has been always considered at the OD level. In this study, we introduce this structural information by explicitly representing trip-chaining within the estimation framework. The advantage is twofold. First, all trips belonging to the same tour can be jointly calibrated. Second, given the estimation during a certain time interval, a prediction of the structural deviation over the whole day can be obtained without the need to run additional simulations. The effectiveness of the proposed methodology is demonstrated first on a toy network and then on a large real-world network. Results show that the model improves the prediction performance with respect to a conventional Kalman Filtering approach. We also show that, on the basis of the estimation of the morning commute, the model can be used to predict the evening commute without need of running additional simulations. [less ▲]

A global optimization heuristic for the decomposed static anticipatory network traffic control problem anticipatory network traffic control problem

in Transportation Research Procedia (2017)

Developing traffic control strategies taking explicitly into account the route choice behavior of users has been widely recognized irregularities in the solution space shape, such as non-convexity and non ... [more ▼]

Developing traffic control strategies taking explicitly into account the route choice behavior of users has been widely recognized irregularities in the solution space shape, such as non-convexity and non-smoothness. In this work, we propose an extended as a very challenging problem. Furthermore, the inclusion of user behavior in optimization based control schemes introduces strong decomposition scheme for the anticipatory traffic control problem, based upon our previous contributions, which aims at i) reducing irregularities in the solution space shape, such as non-convexity and non-smoothness. In this work, we propose an extended the computational complexity of the problem by approaching it in a controller-by-controller fashion, and ii) internalizing specific decomposition scheme for the anticipatory traffic control problem, based upon our previous contributions, which aims at i) reducing constraints in the objective function, guiding the optimization process away from non-significant minima, such as flat regions. the computational complexity of the problem by approaching it in a controller-by-controller fashion, and ii) internalizing specific Through two small scale test networks and different, randomly chosen initial points, we compare how the proposed extension constraints in the objective function, guiding the optimization process away from non-significant minima, such as flat regions. influences optimization results with respect to our previously developed decomposed approach, as well as centralized schemes. Through two small scale test networks and different, randomly chosen initial points, we compare how the proposed extension influences optimization results with respect to our previously developed decomposed approach, as well as centralized schemes. [less ▲]

Estimating Urban Road Traffic States Using Mobile Network Signaling Data

in Abstract book of the 20th International Conference on Intelligent Transportation Systems (2017, October)

It is intuitive that there is a causal relationship between human mobility and signaling events in mobile phone networks. Among these events, not only the initiation of calls and data sessions can be used ... [more ▼]

It is intuitive that there is a causal relationship between human mobility and signaling events in mobile phone networks. Among these events, not only the initiation of calls and data sessions can be used in analyses, but also handovers between different locations that reflect mobility. In this work, we investigate if handovers can be used as a proxy metric for flows in the underlying road network, especially in urban environments. More precisely, we show that characteristic profiles of handovers within and between clusters of mobile network cells exist. We base these profiles on models from road traffic flow theory, and show that they can be used for traffic state estimation using floating-car data as ground truth. The presented model can be beneficial in areas with good mobile network coverage but low road traffic counting infrastructure, e.g. in developing countries, but also serve as an additional predictor for existing traffic state monitoring systems. [less ▲]

The effect of workplace relocation on individuals’ activity travel behaviour

Scientific Conference (2017, July 04)

During working days, home and workplace are anchor locations shaping the daily mobility as well as the employee’s activity pattern. While past research has shown that workplace decentralization is often ... [more ▼]

During working days, home and workplace are anchor locations shaping the daily mobility as well as the employee’s activity pattern. While past research has shown that workplace decentralization is often associated with higher car use for the commuting trip, little is known concerning the effect on activity-travel patterns as whole. The objective of this paper is to assess how workplace decentralization is affecting individuals’ daily activity space. A two-weeks travel diary has been filled by 43 employees of the University of Luxembourg, both before and after the relocation of their workplace. Using descriptive statistics, as well as Standard Deviational Ellipses (SDE) combined with a cluster analysis, results of this paper show that workers’ activity spaces, represented by the Standard Deviational Ellipses, have been importantly modified due to a relocation of a single anchor activity location, i.e. their workplace [less ▲]