The importance of a mobility system based on railway technology as the backbone of public transpo... more The importance of a mobility system based on railway technology as the backbone of public transport is now widely acknowledged. Indeed, rail systems are green, high-performing, smart and able to ensure a high degree of safety. Therefore modal split should be steered towards rail transport by increasing the attractiveness of this transport mode. In this context, a key element is represented by the timetabling design phase, which must aim to guarantee an appropriate degree of robustness of rail operations in order to ensure a high degree of system reliability and increase service quality. A crucial factor in the task of timetabling entails evaluating dwell times at stations. The innovative feature of this paper is the analytical definition of dwell times as flow-dependent. Our proposal is based on estimating dwell times according to the crowding level at platforms and related interaction between passengers and the rail service in terms of user behaviour when a train arrives. An application in the case of a real metro system is provided in order to show the feasibility of the proposed approach.
Keywords: on-platform passenger behaviour; dwell time estimation; timetable design; rail system simulation; microscopic approach.
The aim of this paper is to develop an Information Extension Model (IEM) which uses location data... more The aim of this paper is to develop an Information Extension Model (IEM) which uses location data of bus fleets (AVL data) to estimate road traffic conditions and provide input for implementing control strategies. The IEM consists of three sub-models: the Link Traffic Condition Model (LTCM), the AVL Adaptation Model (AVLAM) and the Network Traffic Condition Model (NTCM). The first provides road traffic conditions as a function of mass-transit traffic conditions in the case of shared lanes, the second provides mass-transit traffic conditions as a function of AVL data, and the last provides road traffic conditions over the whole road network as a function of mass-transit traffic conditions. The IEM (and its sub-models) were developed and calibrated in the case of real dimension networks and some tests were performed on a trial network. Numerical results show the effectiveness of the proposed method since it allows a reduction in travel demand estimation errors. Keywords: Control Management information systems Simulation Transportation Travel demand estimation
International Journal of Transport Development and Integration 2(2), pp. 123-135, 2018
Current techniques of Travel Demand Management (TDM) are based on the simulation of users’ reacti... more Current techniques of Travel Demand Management (TDM) are based on the simulation of users’ reactions to implemented strategies. Indeed, the correct modelling of user behaviour may be considered important for managing public transport systems. Especially in high density contexts, performance of the mass-transit system may represent one of the main tools of decision-makers for affecting users’ choices. In this paper, we focus on the behaviour of users waiting on rail/metro platforms, analysing boarding priorities when a train arrives based on the traditional First In – First Out (FIFO) approach and comparing it with Random In – First Out (RIFO) behaviour. The approaches are then applied in the case of a real metro line operating under different congestion levels.
Keywords: passenger behaviour, traffic assignment models, capacity constraints, rail passenger systems, public transport management, FIFO approach, RIFO approach, microsimulation approach.
Proceedings of the 17th IEEE International Conference on Environment and Electrical Engineering (IEEE EEEIC 2017) and 1st Industrial and Commercial Power Systems Europe (I&CPS 2017), Milan, Italy, June 2017, pp. 722-727, 2017
In recent years the growing interest in environmental issues has prompted researchers to investig... more In recent years the growing interest in environmental issues has prompted researchers to investigate two main areas in the field of rail systems: how to improve performance in order to attract users from other transport modes with greater environmental impacts (such as private cars) and how to reduce energy consumption. On the latter issue, some procedures have been developed for determining suitable ‘green’ driving profiles which are, however, subject to greater travel times. Since precise quantification is critically important, in this paper we propose an approach to determining all operational times analytically, including reserve times. Finally, the methodology is applied in the case of a real metro line for validating the proposal.
Keywords: energy consumption; travel time calculation; metro and rail systems; microsimulation approach.
Proceedings of the 10th International Conference Environmental Engineering (ICEE 2017), Vilnius, Lithuania, April 2017, 2017
Regional rail transport, albeit a major element in public mobility, is frequently affected by gre... more Regional rail transport, albeit a major element in public mobility, is frequently affected by great vulnerability to system failure. Hence it is worth developing suitable procedures to manage rail disruption appropriately. In the particular case of breakdowns, the latter may be managed by means of shunter locomotives or empty rail convoys if the faulty convoy is able to travel in non-autonomous conditions. Obviously, the use of rescue vehicles on the line generates a disturbance with related reductions in service quality. Against this backdrop, this paper has two main aims. First, we investigate the possibility of adopting some unconventional rescue strategies based on the use of operating rail convoys or maintenance vehicles, and propose a methodology, based on a micro-simulation approach, for accurately modelling interactions among all rail system components so as to optimise management in emergency contexts. The second aim is to identify suitable intervention strategies which provide the right balance between the swiftness of rescue operations and the disturbance in-flicted upon rail services during failure management. Finally, the method is applied to the ‘Naples-Sorrento’ regional rail line in southern Italy in order to show the utility and feasibility of the suggested approach.
International Journal of Transport Development and Integration 1(1), pp. 63-73, 2017
In high-density contexts, such as urban or metropolitan areas, decision makers and mobility manag... more In high-density contexts, such as urban or metropolitan areas, decision makers and mobility managers have to adopt suitable strategies to reduce the use of private cars and promote public transport. Indeed, such strategies may help abate the negative impacts of transportation systems (congestion, air and noise pollution, etc.). However, appropriate measures are only effective if based on the provision of high-quality public transport services. Such aims can be achieved by organizing public transport within an integrated framework where rail/metro services are the high-performing mobility backbone and bus services have a feeder function, increasing the geographical coverage of rail services. However, since a faulty train cannot be easily removed or overtaken, a rail/metro system is highly vulnerable to system breakdowns which could entail significant reductions in system quality. Suitable intervention strategies therefore have to be developed to manage rail system emergencies. The aim of this article is to provide a method to determine optimal intervention strategies in the case of a metro system failure. Since in real contexts an exhaustive approach has to be excluded due to the huge number of alternative solutions to be evaluated, it is necessary to adopt or develop appropriate algorithms to obtain sub-optimal solutions within suitable computational times. Hence a Neighbourhood Search Algorithm to identify the optimal solution is applied and tested in the case of a real metro line in order to show the feasibility of our proposal.
Keywords: heuristic algorithms, metro system management, micro-simulation approach, public transport, optimization models, real scale networks.
International Journal of Supply and Operations Management 3(3), pp. 1351-1372, 2016
In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery sol... more In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed rail operations. Indeed, when failures or breakdowns occur during daily service, new strategies have to be implemented so as to react appropriately and re-establish ordinary conditions as rapidly as possible. In this context, the use of rail simulation is vital: for each intervention strategy it provides the evaluation of interactions and performance analysis prior to actually implementing the corrective action. However, in most cases, simulation tasks are deterministic and fail to allow for the stochastic distribution of train performance and delays. Hence, the strategies adopted might not be robust enough to ensure effectiveness of the intervention. We therefore propose an off-line procedure for disruption management based on a microscopic and stochastic rail simulation which considers both service operation and travel demand. An application in the case of a real metro line in Naples (Italy) shows the benefits of the proposed approach in terms of service quality.
Keywords: Sensitivity analysis; public transport management; rail system; travel demand estimation; quality of service.
Transactions on Environment and Electrical Engineering 1(3), pp. 77-85, 2016
A rail system may be considered a useful tool for reducing vehicular flows on a road system (i.e.... more A rail system may be considered a useful tool for reducing vehicular flows on a road system (i.e. cars and trucks), especially in high-density contexts such as urban and metropolitan areas where greenhouse gas emissions need to be abated. In particular, since travellers maximise their own utility, variations in mobility choices can be induced only by significantly improving the level-of-service of public transport. Our specific proposal is to identify the economic and environmental effects of implementing an innovative signalling system (which would reduce passenger waiting times) by performing a cost-benefit analysis based on a feasibility threshold approach. Hence, it is necessary to calculate long-term benefits and compare them with intervention costs. In this context, a key factor to be considered is travel demand estimation in current and future conditions. This approach was tested on a regional rail line in southern Italy to show the feasibility and utility of the proposed methodology.
Keywords: Microscopic rail system simulation, operational cost definition, public transport management, signalling system, travel demand estimation.
Proceedings of the 16th IEEE International Conference on Environment and Electrical Engineering ( IEEE EEEIC 2016), Florence, Italy, June 2016, pp. 251-255, 2016
A rail system represents a useful tool for reducing flows (cars and trucks) on a road system in h... more A rail system represents a useful tool for reducing flows (cars and trucks) on a road system in high density contexts (such as urban and metropolitan areas) with a view to abating greenhouse gas emissions. In particular, since rail passengers maximise their own utility, variations in mobility choices can be induced only by significantly improving the level-of-service of public transport. By defining feasibility thresholds, our proposal is to analyse the economic and environmental feasibility of a new signalling system which would increase service frequencies of a rail system, thereby reducing passenger waiting times. This approach was applied to a regional rail line in southern Italy to show the usefulness of the proposed methodology.
Keywords: Environmental impacts; public transport management; signalling system; travel demand estimation; operational cost definition; microscopic rail system simulation.
International Journal of Mathematical Models and Methods in Applied Sciences 10, pp. 80-86, 2016
Public transport systems represent a potentially effective tool for managing mobility in urban an... more Public transport systems represent a potentially effective tool for managing mobility in urban and metropolitan areas. In particular, especially in high density contexts, rail systems can be adopted as the backbone of transportation services. However, rail systems are also somewhat vulnerable to system failure since, for instance, a faulty train cannot be easily removed or overtaken. Hence, our proposal is to develop an off-line procedure based on a microsimulation approach for analysing the most frequent breakdown conditions and suggesting the adoption of optimal intervention strategies. Finally, different perspectives (i.e. requirements of passengers and rail operators) are proposed and applied in the case of a real metro line in the south of Italy.
Keywords: Failure mitigation, microscopic railway simulation, public transport management, travel demand analysis.
Proceedings of the 2015 AEIT International Annual Conference, 2015
Smart mobility is a key factor in the new conceptual urban development model, the so-called “smar... more Smart mobility is a key factor in the new conceptual urban development model, the so-called “smart city”. We focus on rail and metro transport, proposing a multidimensional constrained optimisation model to carry out a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed operations. Indeed, after the occurrence of a disturbance or disruption, appropriate intervention strategies have to be implemented in order to address the problem and re-establish ordinary daily service conditions as rapidly as possible. The paper specifically aims to improve the traditional deterministic framework, introducing a stochastic disturbance on train performances and delays, in order to simulate operations as closely as possible to reality, with an ad-hoc objective function to be minimised. An application on a real metro line in Naples (Italy) is provided, showing the benefits of the proposed approach.
Proceedings of the 6th International Conference on Automotive and Transportation Systems, 2015
Rail systems represent a useful tool for reducing the use of private cars especially in urban and... more Rail systems represent a useful tool for reducing the use of private cars especially in urban and metropolitan areas. However, since a faulty train cannot be easily removed or overtaken, in the case of rail system failures, restoring operative conditions could take a very long time and result in considerable delays for passengers. In this context, our proposal is to provide rail systems managers (i.e. dispatchers) with an off-line procedure which adopts a microsimulation approach for analysing the most frequent breakdown conditions and suggests in advance the optimal intervention strategies to adopt. In particular, different perspectives are proposed and applied in the case of a real metro line in the south of Italy
Proceedings of the 6th International Conference on Railway Operations Modelling and Analysis, 2015
This paper proposes an off-line procedure for the management of rail-metro networks in the case o... more This paper proposes an off-line procedure for the management of rail-metro networks in the case of high-density, congested cities. Our approach may be considered a decision support system for establishing recovery plans which take customers’ needs into account when service disruption occurs. This new methodology combines a stochastic microscopic simulation of the network and passenger flows so as to evaluate effects of implemented strategies on service quality, simulating rail operations as closely as possible to reality. In other words, in order to analyse the robustness and feasibility of allowable recovery action, the method in question considers the randomness of breakdown occurrence and the variability of both dwell times and travel demand levels at stations. Therefore, user flows are assigned to the network, simulating passenger behaviour on the platforms and especially the dynamic interaction with the rail system. The latter results in a fixed-point problem for the estimation of average dwell times. This, especially in high-density contexts, represents one of the main disturbances of the service and cannot be neglected. Based on this analysis, the stochastic distribution function is evaluated. Finally, an application on a real metro line in the south of Italy is performed to show the effectiveness of the proposed approach.
Proceedings of the 94th Annual Meeting of the Transportation Research Board, 2015
In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery sol... more In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed rail operations. Indeed, when failures or breakdowns occur during daily service, new strategies have to be implemented so as to react appropriately and re-establish ordinary conditions as rapidly as possible. In this context, the use of rail simulation is vital: for each intervention strategy it provides the evaluation of interactions and performance analysis prior to application of corrective action. However, in most cases, simulation tasks are deterministic and fail to allow for the stochastic distribution of train performance and delays. Hence the strategies adopted might not be robust enough to ensure effectiveness of the intervention. We therefore propose an off-line procedure for disruption management based on a microscopic and stochastic rail simulation which considers both service operation and travel demand. An application on a real metro line in Naples (Italy) shows the benefits of the proposed approach in terms of service quality.
Proceedings of IFORS 2014 – 20th Conference on the International Federation of Operational Research Societies, 2014
Due to the constant increase in travel demand, rail systems are more and more dense and service p... more Due to the constant increase in travel demand, rail systems are more and more dense and service providers have the difficult task of planning a timetable which has to be robust and stable. Moreover, in order to increase customers’ satisfaction, it is necessary to provide sufficient transport capacity avoiding train and platform congestion and guaranteeing a good level of service quality. To reach this target, in this framework we provide an appropriate timetable evaluation which considers the dynamic effect of dwell time at station on the service in the case of metro networks.
Proceedings of the 17th Meeting of the Euro Working Group on Transportation, 2014
Rail and metro networks are nowadays the backbone of public transportation systems especially in ... more Rail and metro networks are nowadays the backbone of public transportation systems especially in high density contexts. Due to the constant increase in travel demand, rail systems are more and more dense and service providers have the difficult task of planning a timetable which has to be robust and stable. Moreover, in order to increase customers’ satisfaction, it is necessary to provide sufficient transport capacity avoiding train and platform congestion and guaranteeing a good level of service quality. To reach this target, an appropriate timetable evaluation, which expresses the interactions between train operation and passenger flows, is essential. In particular, the aim of the paper is to analyse the dynamic effect of dwell time at station on the service in the case of metro networks. In fact, above all in crowded situations, train can be forced to remain stopped in a station more time than what has been planned, causing a delay. As a consequence, the more a train is delayed, the more the passengers arrive at the station and get on the train further increasing the dwell time. The evaluation of this dynamic effect, known in the literature as “snowball effect”, provides an analysis of the timetable which is as closely as possible to the real phenomenon and, above all, yields an estimation of the effective congestion of carriages. Hence, by adopting suitable indexes which reflect passenger experiences of the service, it is possible to establish an appropriate evaluation method for planning train operations. An application on a real metro line in the city of Naples (Italy) has been applied in order to show the utility of the proposed approach.
Journal of Applied Sciences 14(21), pp. 2767-2781, 2014
In this paper a model for the optimisation of mass-transit fares is proposed and tested both on a... more In this paper a model for the optimisation of mass-transit fares is proposed and tested both on a trial and a real-scale network. Formulated as a multidimensional constrained minimisation model, the problem considers a multimodal transportation system under the assumption of elastic demand for simulating the impacts of fare policies on modal split and network performance. We suggest that the proposed model is applied with the adoption of two objective functions in order to take into account all system and social costs: (mass-transit and road) user costs, firm costs and external costs. Numerical tests show that the main constraints in fare definition are related to the size of public transport subsidies provided by public administration.
Keywords: public transport, fare optimisation, elastic demand, multimodal models, external costs.
Lecture Notes in Computer Science 8353, pp. 215-222, 2014
In this paper we propose a general model for solving the Transportation Network Design Problem (T... more In this paper we propose a general model for solving the Transportation Network Design Problem (TNDP). Since in real-scale networks the number of feasible solutions to be examined does not allow an exhaustive search and objective functions are not convex, it is necessary to adopt metaheuristic algorithms to obtain sub-optimal solutions within suitable calculation times. Hence, we show and analyse some algorithms proposed in the literature for solving TNDPs both in urban and extra-urban contexts in order to highlight the importance of metaheuristic algorithms in large-scale transportation problems.
WIT Transactions on the Built Environment 135, pp. 509-521, 2014
The management of public transport for rebalancing the use of transportation systems is a useful ... more The management of public transport for rebalancing the use of transportation systems is a useful tool for reducing negative externalities without excessively affecting zone accessibility. In this context, a rail or metro system can be a key element for producing a high-quality supply of public transport. Obviously, due to the great vulnerability of rail technology to system failures, it is necessary to develop suitable tools to identify rapidly, even with off-line procedures, the best operational strategies which minimise user discomfort produced by such failures. Hence, our proposal is to extend previous models proposed in the literature by considering travel demand as an outcome of a random variable and not only in terms of average values. The proposed approach is applied in the case of a real dimension metro network, considering a wider class of failure contexts.
Keywords: metro system management, rail passenger systems, microsimulation approach, travel demand analysis, capacity constraints, public transport.
WIT Transactions on the Built Environment 138, pp. 77-88, 2014
The planning of an efficient and effective public transport system is a key element in managing m... more The planning of an efficient and effective public transport system is a key element in managing modern mobility both in densely populated urban areas and in peripheral and/or rural areas where the population densities are considerably lower. Indeed, the presence of public transport designed to meet travel demand could allow a reduction in negative externalities produced by private cars without excessively penalising user travel times or accessibility to different zones. However, the recent financial crisis has forced many public administrations to reduce resources allocated to public services and replan related services in order to mitigate negative effects on users. In this context, we propose two methods for replanning public transport services in the case of budget reductions. The first approach, indicated as CLP (Change the Least Possible), can be adopted when the initial services are actually able to satisfy user needs and in some time slots are probably surplus to requirements. The second approach, CFR (Change the FRamework), instead, should be used when the initial services are already inadequate or barely sufficient to serve users in the study area. Indeed, in the latter case, it is very difficult to eliminate some runs without producing a significant reduction in levels of service. Finally, the proposed methodology has been applied by our research group when replanning bus services in the provinces of Naples and Avellino, in southern Italy, where we implemented respectively the CLP and CFR approaches by solving some problems related to interference with pre-existing planning tools.
Keywords: public transport services, planning methods, mass-transit network design, real network analysis.
The importance of a mobility system based on railway technology as the backbone of public transpo... more The importance of a mobility system based on railway technology as the backbone of public transport is now widely acknowledged. Indeed, rail systems are green, high-performing, smart and able to ensure a high degree of safety. Therefore modal split should be steered towards rail transport by increasing the attractiveness of this transport mode. In this context, a key element is represented by the timetabling design phase, which must aim to guarantee an appropriate degree of robustness of rail operations in order to ensure a high degree of system reliability and increase service quality. A crucial factor in the task of timetabling entails evaluating dwell times at stations. The innovative feature of this paper is the analytical definition of dwell times as flow-dependent. Our proposal is based on estimating dwell times according to the crowding level at platforms and related interaction between passengers and the rail service in terms of user behaviour when a train arrives. An application in the case of a real metro system is provided in order to show the feasibility of the proposed approach.
Keywords: on-platform passenger behaviour; dwell time estimation; timetable design; rail system simulation; microscopic approach.
The aim of this paper is to develop an Information Extension Model (IEM) which uses location data... more The aim of this paper is to develop an Information Extension Model (IEM) which uses location data of bus fleets (AVL data) to estimate road traffic conditions and provide input for implementing control strategies. The IEM consists of three sub-models: the Link Traffic Condition Model (LTCM), the AVL Adaptation Model (AVLAM) and the Network Traffic Condition Model (NTCM). The first provides road traffic conditions as a function of mass-transit traffic conditions in the case of shared lanes, the second provides mass-transit traffic conditions as a function of AVL data, and the last provides road traffic conditions over the whole road network as a function of mass-transit traffic conditions. The IEM (and its sub-models) were developed and calibrated in the case of real dimension networks and some tests were performed on a trial network. Numerical results show the effectiveness of the proposed method since it allows a reduction in travel demand estimation errors. Keywords: Control Management information systems Simulation Transportation Travel demand estimation
International Journal of Transport Development and Integration 2(2), pp. 123-135, 2018
Current techniques of Travel Demand Management (TDM) are based on the simulation of users’ reacti... more Current techniques of Travel Demand Management (TDM) are based on the simulation of users’ reactions to implemented strategies. Indeed, the correct modelling of user behaviour may be considered important for managing public transport systems. Especially in high density contexts, performance of the mass-transit system may represent one of the main tools of decision-makers for affecting users’ choices. In this paper, we focus on the behaviour of users waiting on rail/metro platforms, analysing boarding priorities when a train arrives based on the traditional First In – First Out (FIFO) approach and comparing it with Random In – First Out (RIFO) behaviour. The approaches are then applied in the case of a real metro line operating under different congestion levels.
Keywords: passenger behaviour, traffic assignment models, capacity constraints, rail passenger systems, public transport management, FIFO approach, RIFO approach, microsimulation approach.
Proceedings of the 17th IEEE International Conference on Environment and Electrical Engineering (IEEE EEEIC 2017) and 1st Industrial and Commercial Power Systems Europe (I&CPS 2017), Milan, Italy, June 2017, pp. 722-727, 2017
In recent years the growing interest in environmental issues has prompted researchers to investig... more In recent years the growing interest in environmental issues has prompted researchers to investigate two main areas in the field of rail systems: how to improve performance in order to attract users from other transport modes with greater environmental impacts (such as private cars) and how to reduce energy consumption. On the latter issue, some procedures have been developed for determining suitable ‘green’ driving profiles which are, however, subject to greater travel times. Since precise quantification is critically important, in this paper we propose an approach to determining all operational times analytically, including reserve times. Finally, the methodology is applied in the case of a real metro line for validating the proposal.
Keywords: energy consumption; travel time calculation; metro and rail systems; microsimulation approach.
Proceedings of the 10th International Conference Environmental Engineering (ICEE 2017), Vilnius, Lithuania, April 2017, 2017
Regional rail transport, albeit a major element in public mobility, is frequently affected by gre... more Regional rail transport, albeit a major element in public mobility, is frequently affected by great vulnerability to system failure. Hence it is worth developing suitable procedures to manage rail disruption appropriately. In the particular case of breakdowns, the latter may be managed by means of shunter locomotives or empty rail convoys if the faulty convoy is able to travel in non-autonomous conditions. Obviously, the use of rescue vehicles on the line generates a disturbance with related reductions in service quality. Against this backdrop, this paper has two main aims. First, we investigate the possibility of adopting some unconventional rescue strategies based on the use of operating rail convoys or maintenance vehicles, and propose a methodology, based on a micro-simulation approach, for accurately modelling interactions among all rail system components so as to optimise management in emergency contexts. The second aim is to identify suitable intervention strategies which provide the right balance between the swiftness of rescue operations and the disturbance in-flicted upon rail services during failure management. Finally, the method is applied to the ‘Naples-Sorrento’ regional rail line in southern Italy in order to show the utility and feasibility of the suggested approach.
International Journal of Transport Development and Integration 1(1), pp. 63-73, 2017
In high-density contexts, such as urban or metropolitan areas, decision makers and mobility manag... more In high-density contexts, such as urban or metropolitan areas, decision makers and mobility managers have to adopt suitable strategies to reduce the use of private cars and promote public transport. Indeed, such strategies may help abate the negative impacts of transportation systems (congestion, air and noise pollution, etc.). However, appropriate measures are only effective if based on the provision of high-quality public transport services. Such aims can be achieved by organizing public transport within an integrated framework where rail/metro services are the high-performing mobility backbone and bus services have a feeder function, increasing the geographical coverage of rail services. However, since a faulty train cannot be easily removed or overtaken, a rail/metro system is highly vulnerable to system breakdowns which could entail significant reductions in system quality. Suitable intervention strategies therefore have to be developed to manage rail system emergencies. The aim of this article is to provide a method to determine optimal intervention strategies in the case of a metro system failure. Since in real contexts an exhaustive approach has to be excluded due to the huge number of alternative solutions to be evaluated, it is necessary to adopt or develop appropriate algorithms to obtain sub-optimal solutions within suitable computational times. Hence a Neighbourhood Search Algorithm to identify the optimal solution is applied and tested in the case of a real metro line in order to show the feasibility of our proposal.
Keywords: heuristic algorithms, metro system management, micro-simulation approach, public transport, optimization models, real scale networks.
International Journal of Supply and Operations Management 3(3), pp. 1351-1372, 2016
In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery sol... more In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed rail operations. Indeed, when failures or breakdowns occur during daily service, new strategies have to be implemented so as to react appropriately and re-establish ordinary conditions as rapidly as possible. In this context, the use of rail simulation is vital: for each intervention strategy it provides the evaluation of interactions and performance analysis prior to actually implementing the corrective action. However, in most cases, simulation tasks are deterministic and fail to allow for the stochastic distribution of train performance and delays. Hence, the strategies adopted might not be robust enough to ensure effectiveness of the intervention. We therefore propose an off-line procedure for disruption management based on a microscopic and stochastic rail simulation which considers both service operation and travel demand. An application in the case of a real metro line in Naples (Italy) shows the benefits of the proposed approach in terms of service quality.
Keywords: Sensitivity analysis; public transport management; rail system; travel demand estimation; quality of service.
Transactions on Environment and Electrical Engineering 1(3), pp. 77-85, 2016
A rail system may be considered a useful tool for reducing vehicular flows on a road system (i.e.... more A rail system may be considered a useful tool for reducing vehicular flows on a road system (i.e. cars and trucks), especially in high-density contexts such as urban and metropolitan areas where greenhouse gas emissions need to be abated. In particular, since travellers maximise their own utility, variations in mobility choices can be induced only by significantly improving the level-of-service of public transport. Our specific proposal is to identify the economic and environmental effects of implementing an innovative signalling system (which would reduce passenger waiting times) by performing a cost-benefit analysis based on a feasibility threshold approach. Hence, it is necessary to calculate long-term benefits and compare them with intervention costs. In this context, a key factor to be considered is travel demand estimation in current and future conditions. This approach was tested on a regional rail line in southern Italy to show the feasibility and utility of the proposed methodology.
Keywords: Microscopic rail system simulation, operational cost definition, public transport management, signalling system, travel demand estimation.
Proceedings of the 16th IEEE International Conference on Environment and Electrical Engineering ( IEEE EEEIC 2016), Florence, Italy, June 2016, pp. 251-255, 2016
A rail system represents a useful tool for reducing flows (cars and trucks) on a road system in h... more A rail system represents a useful tool for reducing flows (cars and trucks) on a road system in high density contexts (such as urban and metropolitan areas) with a view to abating greenhouse gas emissions. In particular, since rail passengers maximise their own utility, variations in mobility choices can be induced only by significantly improving the level-of-service of public transport. By defining feasibility thresholds, our proposal is to analyse the economic and environmental feasibility of a new signalling system which would increase service frequencies of a rail system, thereby reducing passenger waiting times. This approach was applied to a regional rail line in southern Italy to show the usefulness of the proposed methodology.
Keywords: Environmental impacts; public transport management; signalling system; travel demand estimation; operational cost definition; microscopic rail system simulation.
International Journal of Mathematical Models and Methods in Applied Sciences 10, pp. 80-86, 2016
Public transport systems represent a potentially effective tool for managing mobility in urban an... more Public transport systems represent a potentially effective tool for managing mobility in urban and metropolitan areas. In particular, especially in high density contexts, rail systems can be adopted as the backbone of transportation services. However, rail systems are also somewhat vulnerable to system failure since, for instance, a faulty train cannot be easily removed or overtaken. Hence, our proposal is to develop an off-line procedure based on a microsimulation approach for analysing the most frequent breakdown conditions and suggesting the adoption of optimal intervention strategies. Finally, different perspectives (i.e. requirements of passengers and rail operators) are proposed and applied in the case of a real metro line in the south of Italy.
Keywords: Failure mitigation, microscopic railway simulation, public transport management, travel demand analysis.
Proceedings of the 2015 AEIT International Annual Conference, 2015
Smart mobility is a key factor in the new conceptual urban development model, the so-called “smar... more Smart mobility is a key factor in the new conceptual urban development model, the so-called “smart city”. We focus on rail and metro transport, proposing a multidimensional constrained optimisation model to carry out a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed operations. Indeed, after the occurrence of a disturbance or disruption, appropriate intervention strategies have to be implemented in order to address the problem and re-establish ordinary daily service conditions as rapidly as possible. The paper specifically aims to improve the traditional deterministic framework, introducing a stochastic disturbance on train performances and delays, in order to simulate operations as closely as possible to reality, with an ad-hoc objective function to be minimised. An application on a real metro line in Naples (Italy) is provided, showing the benefits of the proposed approach.
Proceedings of the 6th International Conference on Automotive and Transportation Systems, 2015
Rail systems represent a useful tool for reducing the use of private cars especially in urban and... more Rail systems represent a useful tool for reducing the use of private cars especially in urban and metropolitan areas. However, since a faulty train cannot be easily removed or overtaken, in the case of rail system failures, restoring operative conditions could take a very long time and result in considerable delays for passengers. In this context, our proposal is to provide rail systems managers (i.e. dispatchers) with an off-line procedure which adopts a microsimulation approach for analysing the most frequent breakdown conditions and suggests in advance the optimal intervention strategies to adopt. In particular, different perspectives are proposed and applied in the case of a real metro line in the south of Italy
Proceedings of the 6th International Conference on Railway Operations Modelling and Analysis, 2015
This paper proposes an off-line procedure for the management of rail-metro networks in the case o... more This paper proposes an off-line procedure for the management of rail-metro networks in the case of high-density, congested cities. Our approach may be considered a decision support system for establishing recovery plans which take customers’ needs into account when service disruption occurs. This new methodology combines a stochastic microscopic simulation of the network and passenger flows so as to evaluate effects of implemented strategies on service quality, simulating rail operations as closely as possible to reality. In other words, in order to analyse the robustness and feasibility of allowable recovery action, the method in question considers the randomness of breakdown occurrence and the variability of both dwell times and travel demand levels at stations. Therefore, user flows are assigned to the network, simulating passenger behaviour on the platforms and especially the dynamic interaction with the rail system. The latter results in a fixed-point problem for the estimation of average dwell times. This, especially in high-density contexts, represents one of the main disturbances of the service and cannot be neglected. Based on this analysis, the stochastic distribution function is evaluated. Finally, an application on a real metro line in the south of Italy is performed to show the effectiveness of the proposed approach.
Proceedings of the 94th Annual Meeting of the Transportation Research Board, 2015
In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery sol... more In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed rail operations. Indeed, when failures or breakdowns occur during daily service, new strategies have to be implemented so as to react appropriately and re-establish ordinary conditions as rapidly as possible. In this context, the use of rail simulation is vital: for each intervention strategy it provides the evaluation of interactions and performance analysis prior to application of corrective action. However, in most cases, simulation tasks are deterministic and fail to allow for the stochastic distribution of train performance and delays. Hence the strategies adopted might not be robust enough to ensure effectiveness of the intervention. We therefore propose an off-line procedure for disruption management based on a microscopic and stochastic rail simulation which considers both service operation and travel demand. An application on a real metro line in Naples (Italy) shows the benefits of the proposed approach in terms of service quality.
Proceedings of IFORS 2014 – 20th Conference on the International Federation of Operational Research Societies, 2014
Due to the constant increase in travel demand, rail systems are more and more dense and service p... more Due to the constant increase in travel demand, rail systems are more and more dense and service providers have the difficult task of planning a timetable which has to be robust and stable. Moreover, in order to increase customers’ satisfaction, it is necessary to provide sufficient transport capacity avoiding train and platform congestion and guaranteeing a good level of service quality. To reach this target, in this framework we provide an appropriate timetable evaluation which considers the dynamic effect of dwell time at station on the service in the case of metro networks.
Proceedings of the 17th Meeting of the Euro Working Group on Transportation, 2014
Rail and metro networks are nowadays the backbone of public transportation systems especially in ... more Rail and metro networks are nowadays the backbone of public transportation systems especially in high density contexts. Due to the constant increase in travel demand, rail systems are more and more dense and service providers have the difficult task of planning a timetable which has to be robust and stable. Moreover, in order to increase customers’ satisfaction, it is necessary to provide sufficient transport capacity avoiding train and platform congestion and guaranteeing a good level of service quality. To reach this target, an appropriate timetable evaluation, which expresses the interactions between train operation and passenger flows, is essential. In particular, the aim of the paper is to analyse the dynamic effect of dwell time at station on the service in the case of metro networks. In fact, above all in crowded situations, train can be forced to remain stopped in a station more time than what has been planned, causing a delay. As a consequence, the more a train is delayed, the more the passengers arrive at the station and get on the train further increasing the dwell time. The evaluation of this dynamic effect, known in the literature as “snowball effect”, provides an analysis of the timetable which is as closely as possible to the real phenomenon and, above all, yields an estimation of the effective congestion of carriages. Hence, by adopting suitable indexes which reflect passenger experiences of the service, it is possible to establish an appropriate evaluation method for planning train operations. An application on a real metro line in the city of Naples (Italy) has been applied in order to show the utility of the proposed approach.
Journal of Applied Sciences 14(21), pp. 2767-2781, 2014
In this paper a model for the optimisation of mass-transit fares is proposed and tested both on a... more In this paper a model for the optimisation of mass-transit fares is proposed and tested both on a trial and a real-scale network. Formulated as a multidimensional constrained minimisation model, the problem considers a multimodal transportation system under the assumption of elastic demand for simulating the impacts of fare policies on modal split and network performance. We suggest that the proposed model is applied with the adoption of two objective functions in order to take into account all system and social costs: (mass-transit and road) user costs, firm costs and external costs. Numerical tests show that the main constraints in fare definition are related to the size of public transport subsidies provided by public administration.
Keywords: public transport, fare optimisation, elastic demand, multimodal models, external costs.
Lecture Notes in Computer Science 8353, pp. 215-222, 2014
In this paper we propose a general model for solving the Transportation Network Design Problem (T... more In this paper we propose a general model for solving the Transportation Network Design Problem (TNDP). Since in real-scale networks the number of feasible solutions to be examined does not allow an exhaustive search and objective functions are not convex, it is necessary to adopt metaheuristic algorithms to obtain sub-optimal solutions within suitable calculation times. Hence, we show and analyse some algorithms proposed in the literature for solving TNDPs both in urban and extra-urban contexts in order to highlight the importance of metaheuristic algorithms in large-scale transportation problems.
WIT Transactions on the Built Environment 135, pp. 509-521, 2014
The management of public transport for rebalancing the use of transportation systems is a useful ... more The management of public transport for rebalancing the use of transportation systems is a useful tool for reducing negative externalities without excessively affecting zone accessibility. In this context, a rail or metro system can be a key element for producing a high-quality supply of public transport. Obviously, due to the great vulnerability of rail technology to system failures, it is necessary to develop suitable tools to identify rapidly, even with off-line procedures, the best operational strategies which minimise user discomfort produced by such failures. Hence, our proposal is to extend previous models proposed in the literature by considering travel demand as an outcome of a random variable and not only in terms of average values. The proposed approach is applied in the case of a real dimension metro network, considering a wider class of failure contexts.
Keywords: metro system management, rail passenger systems, microsimulation approach, travel demand analysis, capacity constraints, public transport.
WIT Transactions on the Built Environment 138, pp. 77-88, 2014
The planning of an efficient and effective public transport system is a key element in managing m... more The planning of an efficient and effective public transport system is a key element in managing modern mobility both in densely populated urban areas and in peripheral and/or rural areas where the population densities are considerably lower. Indeed, the presence of public transport designed to meet travel demand could allow a reduction in negative externalities produced by private cars without excessively penalising user travel times or accessibility to different zones. However, the recent financial crisis has forced many public administrations to reduce resources allocated to public services and replan related services in order to mitigate negative effects on users. In this context, we propose two methods for replanning public transport services in the case of budget reductions. The first approach, indicated as CLP (Change the Least Possible), can be adopted when the initial services are actually able to satisfy user needs and in some time slots are probably surplus to requirements. The second approach, CFR (Change the FRamework), instead, should be used when the initial services are already inadequate or barely sufficient to serve users in the study area. Indeed, in the latter case, it is very difficult to eliminate some runs without producing a significant reduction in levels of service. Finally, the proposed methodology has been applied by our research group when replanning bus services in the provinces of Naples and Avellino, in southern Italy, where we implemented respectively the CLP and CFR approaches by solving some problems related to interference with pre-existing planning tools.
Keywords: public transport services, planning methods, mass-transit network design, real network analysis.
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Papers by Bruno Montella
Keywords: on-platform passenger behaviour; dwell time estimation; timetable design; rail system simulation; microscopic approach.
fleets (AVL data) to estimate road traffic conditions and provide input for implementing control strategies.
The IEM consists of three sub-models: the Link Traffic Condition Model (LTCM), the AVL Adaptation
Model (AVLAM) and the Network Traffic Condition Model (NTCM). The first provides road traffic conditions
as a function of mass-transit traffic conditions in the case of shared lanes, the second provides mass-transit
traffic conditions as a function of AVL data, and the last provides road traffic conditions over the whole
road network as a function of mass-transit traffic conditions.
The IEM (and its sub-models) were developed and calibrated in the case of real dimension networks
and some tests were performed on a trial network. Numerical results show the effectiveness of the proposed
method since it allows a reduction in travel demand estimation errors.
Keywords:
Control Management information systems Simulation Transportation Travel demand estimation
Keywords: passenger behaviour, traffic assignment models, capacity constraints, rail passenger systems, public transport management, FIFO approach, RIFO approach, microsimulation approach.
Keywords: energy consumption; travel time calculation; metro and rail systems; microsimulation approach.
Keywords: regional railways; micro-simulation approach; travel demand estimation; disruption management, rescue ve-hicles.
Keywords: heuristic algorithms, metro system management, micro-simulation approach, public transport, optimization models, real scale networks.
Keywords: Sensitivity analysis; public transport management; rail system; travel demand estimation; quality of service.
Keywords: Microscopic rail system simulation, operational cost definition, public transport management, signalling system, travel demand estimation.
Keywords: Environmental impacts; public transport management; signalling system; travel demand estimation; operational cost definition; microscopic rail system simulation.
Keywords: Failure mitigation, microscopic railway simulation, public transport management, travel demand analysis.
Keywords: public transport, fare optimisation, elastic demand, multimodal models, external costs.
Keywords: Transportation, Network design, Metaheuristic algorithms, Real-scale networks.
Keywords: metro system management, rail passenger systems, microsimulation approach, travel demand analysis, capacity constraints, public transport.
Keywords: public transport services, planning methods, mass-transit network design, real network analysis.
Keywords: on-platform passenger behaviour; dwell time estimation; timetable design; rail system simulation; microscopic approach.
fleets (AVL data) to estimate road traffic conditions and provide input for implementing control strategies.
The IEM consists of three sub-models: the Link Traffic Condition Model (LTCM), the AVL Adaptation
Model (AVLAM) and the Network Traffic Condition Model (NTCM). The first provides road traffic conditions
as a function of mass-transit traffic conditions in the case of shared lanes, the second provides mass-transit
traffic conditions as a function of AVL data, and the last provides road traffic conditions over the whole
road network as a function of mass-transit traffic conditions.
The IEM (and its sub-models) were developed and calibrated in the case of real dimension networks
and some tests were performed on a trial network. Numerical results show the effectiveness of the proposed
method since it allows a reduction in travel demand estimation errors.
Keywords:
Control Management information systems Simulation Transportation Travel demand estimation
Keywords: passenger behaviour, traffic assignment models, capacity constraints, rail passenger systems, public transport management, FIFO approach, RIFO approach, microsimulation approach.
Keywords: energy consumption; travel time calculation; metro and rail systems; microsimulation approach.
Keywords: regional railways; micro-simulation approach; travel demand estimation; disruption management, rescue ve-hicles.
Keywords: heuristic algorithms, metro system management, micro-simulation approach, public transport, optimization models, real scale networks.
Keywords: Sensitivity analysis; public transport management; rail system; travel demand estimation; quality of service.
Keywords: Microscopic rail system simulation, operational cost definition, public transport management, signalling system, travel demand estimation.
Keywords: Environmental impacts; public transport management; signalling system; travel demand estimation; operational cost definition; microscopic rail system simulation.
Keywords: Failure mitigation, microscopic railway simulation, public transport management, travel demand analysis.
Keywords: public transport, fare optimisation, elastic demand, multimodal models, external costs.
Keywords: Transportation, Network design, Metaheuristic algorithms, Real-scale networks.
Keywords: metro system management, rail passenger systems, microsimulation approach, travel demand analysis, capacity constraints, public transport.
Keywords: public transport services, planning methods, mass-transit network design, real network analysis.