- Sapienza University of Rome
Dept. Civil, Constructional and Environmental Engineering
Via Eudossiana, 18
00184 Roma (IT)
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In this paper, a general analysis methodology aimed at processing a large set of Floating Car Data (FCD) – reconstructing the routes followed by the drivers and then clustering them to achieve suitable choice sets– is applied to a broad... more
In this paper, a general analysis methodology aimed at processing a large set of Floating Car Data (FCD) – reconstructing the routes followed by the drivers and then clustering them to achieve suitable choice sets– is applied to a broad set of FCD collected in the metropolitan city of Rome over six months. Through the observation of about 10,000 trips, an analysis of Wardrop’s principle is carried out focused on the morning peak period: the results show that about 75% of the routes chosen by the users have travel times that exceed the minimum value by less than 35%, a value having the same magnitude of the average coefficient of variation of the observed link travel times, that is 24%. The possibility of modeling drivers’ route choice behavior among a set of similar routes is investigated, and different utility functional forms are defined and calibrated. The values of ρ2 obtained are low, as expected considering that the drivers mostly perceive the routes that were actually chosen as equivalent alternatives. Nevertheless, the coefficients' values are statistically significant: results confirmed that length, travel time, and traffic lights represent three attributes that affect the path choice mechanism with a probability of 95%. Finally, the users’ process to improve their choice is also investigated, and the day-to-day route and departure time choice processes are analyzed to verify the possible existence of a correlation between observed changes and possible delays experienced by the users in the days before the change: for travel time increases or reductions between 5 and 20 minutes, a correlation has been identified with the number of route changes.
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One of the open challenges in transport modelling is to estimate within-day demand flows that reflect the complexity of individual activity-travel behaviour. While disaggregate (Activity-Based) demand models can recreate realistic daily... more
One of the open challenges in transport modelling is to estimate within-day demand flows that reflect the complexity of individual activity-travel behaviour. While disaggregate (Activity-Based) demand models can recreate realistic daily mobility patterns at an individual level, they usually require an accurate knowledge of individual user behaviour (i.e. via travel surveys), which is not always available. As a result, practitioners often turn to aggregate demand models, that have the advantage of being less demanding in terms of data but typically under represent the demand for secondary activities.In this work, we take research on within-day demand modelling one step forward by proposing a framework that combines traditional methodologies with heterogeneous data sources in order to explicitly represent trip chaining at an aggregated level. We show that the combination of web-based crowd sensed data, network data and behavioural constraints allows to capture complex spatial and temporal correlations between demand patterns. The methodology is applied on the classical Gravity model to show how to incorporate within-day dynamics. Yet, any alternative demand model can be adopted. In our case, Generation and Attraction are used to estimate the systematic demand, that is enriched of information about individual activity patterns, and then a novel definition of impedance function based on Hagestraand ellipse theory plays a central role in spatially distributing locations of trips using geographic relationships and constraints deriving from space-time behaviour.A case study for Luxembourg City has been presented to show the potential of the methodology: the choice of using data from a different spatial context to account for the temporal dimension has been validated through comparisons with official statistics. The results of simulating a workplace relocation show the advantages of this new approach in representing demand related to secondary activities.
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Il software SINTAC applica diversi metodi di regolazione del traffico (massima banda, minimo ritardo) ed integra diverse procedure euristiche per la regolazione delle arterie sincronizzate, tenendo conto anche della presenza di... more
Il software SINTAC applica diversi metodi di regolazione del traffico (massima banda, minimo ritardo) ed integra diverse procedure euristiche per la regolazione delle arterie sincronizzate, tenendo conto anche della presenza di trattamento preferenziale degli autobus. Il modello di traffico utilizzato tiene conto sia della variabilità temporale della domanda, con conseguente possibilità di temporanea sovra-saturazione, sia del possibile effetto di spill-back delle code sulla capacità dei nodi a monte
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Abstract Objective Given the strong relationship between road accident and traffic speed, the evaluation and prediction of this latter have always been considered as a critical issue for road safety analysis and for the evaluation of road... more
Abstract Objective Given the strong relationship between road accident and traffic speed, the evaluation and prediction of this latter have always been considered as a critical issue for road safety analysis and for the evaluation of road network safety improvements. Prediction models developed to date mainly focused on spot speed in a rural environment or on running speed in an urban one. Very few analyze the speed estimation in “transition” areas. The objective of this paper is to develop a generalized speed estimation model able to predict mean speed in urban, rural, and “transition” environment as a function of road layout characteristics. It is believed that the proposed estimation tool can be effectively employed by road engineers in the road safety design and retrofitting stage. Methods The basic idea of the paper is to shed some light on this issue by making use of a hybrid estimation approach able to combine the information gathered from both previously mentioned models within a generalized speed adaptation framework that reflects road user behavior. The calibration and validation of the generalized estimation model have been carried out following a collection of Floating Car Data (FCD) on several candidate sites. Results Preliminary results seem to indicate that the methodology proposed may be effective in estimating the spot speed in two-lane rural and urban arterials. Conclusions FCD data can be useful to develop more efficient estimation models to better manage the safety of urban and rural roads.
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Abstract The paper describes research activities of monitoring, modeling, and planning of people mobility in Rome during the Covid-19 epidemic period from March to June 2020. The results of data collection for different transport modes... more
Abstract The paper describes research activities of monitoring, modeling, and planning of people mobility in Rome during the Covid-19 epidemic period from March to June 2020. The results of data collection for different transport modes (walking, bicycle, car, and transit) are presented and analyzed. A specific focus is provided for the subway mass transit, where 1 m interpersonal distancing is required to prevent the risks for Covid-19 contagion together with the use of masks and gloves. A transport system model has been calibrated on the data collected during the lockdown period –when people’s behavior significantly changed because of smart-working adoption and contagion fear– and was applied to predict future mobility scenarios under different assumptions on economic activities restarting. Based on the estimations of passenger loading, a timing policy that differentiates the opening hours of the shops depending on their commercial category was implemented, and an additional bus transit service was introduced to avoid incompatible loads of the subway lines with the required interpersonal distancing.
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Synopsis The Forum of European National Highway Research Laboratories (FEHRL) was formed in 1989 by the National Highway Research Laboratories in EU and EFTA countries. The mission of FEHRL is to promote and facilitate collaboration... more
Synopsis The Forum of European National Highway Research Laboratories (FEHRL) was formed in 1989 by the National Highway Research Laboratories in EU and EFTA countries. The mission of FEHRL is to promote and facilitate collaboration between its institutes and provide high quality information and advice to governments, the European Commission, the road industry and road users on technologies and policies related to roads. To promote common research activities a five-year Strategic European Road Research Programme ( ...
Most road accidents occur in urban areas and notably at urban intersections, where cyclists and motorcyclists are the most vulnerable. In the last few years, cycling mobility has been growing; therefore, bike infrastructures should be... more
Most road accidents occur in urban areas and notably at urban intersections, where cyclists and motorcyclists are the most vulnerable. In the last few years, cycling mobility has been growing; therefore, bike infrastructures should be designed to encourage this type of mobility and reduce motorized and/or private transport. The paper presents a study to implement a new cycle path in the existing cycle and road network in Rome, Italy. The geometric design of the new path complies with Italian standards regarding the technical characteristics of bicycle paths, while the Highway Capacity Manual has been considered for the traffic analysis. In particular, a before-after approach has been adopted to examine and compare the traffic flow at more complex and congested intersections where the cycle path will pass. Trams, buses, cars, bikes and pedestrians were the traffic components considered in each analysis. The software package PTV VISSIM 8 allowed the simulations of traffic flows at tra...
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The paper deals with the problem of minimizing reshuffling of containers in an inland intermodal terminal. The problem is tackled according to a simulation-optimization approach. A simulation model computes the operational costs of... more
The paper deals with the problem of minimizing reshuffling of containers in an inland intermodal terminal. The problem is tackled according to a simulation-optimization approach. A simulation model computes the operational costs of containers, related to storage and pick-up operations in an inland yard. The optimization is carried out by two genetic algorithms that work in series. The introduction of the second genetic algorithm and the concept of trust region are the original contributions of the paper to the literature. The proposed optimization method has been tested on a theoretical example of realistic size. Results highlighted that the double genetic algorithm reduces the total operational costs by 7% with respect to the single genetic algorithm.
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This paper presents the results of a study on the Rome mobility system aiming at estimating the impacts of the progressive lockdown, imposed by the government, due to the Covid-19 pandemic as well as to support decision makers in planning... more
This paper presents the results of a study on the Rome mobility system aiming at estimating the impacts of the progressive lockdown, imposed by the government, due to the Covid-19 pandemic as well as to support decision makers in planning the transport system for the restart towards a post-Covid “new normal”. The analysis of data obtained by the transport monitoring system has been fundamental for both investigating effects of the lockdown and feeding transport models to predict the impacts on future actions. At first, the paper focuses on the so-called transport analytics, by describing mobility trends for the multimodal transportation system of Rome. Then, the results of the simulated scenarios to design public transport services, able to ensure passengers social distancing required in the first post-Covid months, are presented and discussed.
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Short-term traffic forecasting is driven by an increasing need of new services for user information and new systems for dynamic control. Our research focuses on reproducing anticipated traffic conditions by means of statistical methods... more
Short-term traffic forecasting is driven by an increasing need of new services for user information and new systems for dynamic control. Our research focuses on reproducing anticipated traffic conditions by means of statistical methods traditionally applied in artificial intelligence problems. Although we strongly believe that the effects of specific traffic events can only be predicted through transportation model based simulations in real-time, yet the fluctuations affecting the ordinary traffic conditions of a day-type can well be forecasted without.
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E-mail: gennaro. ciccarelli@ uniroma1. it, chiara. colombaroni@ uniroma1. it, gaetano. fusco@ uniroma1. it 2 Department of Civil Engineering, Roma Tre University Via Vito Volterra 62, 00139, Rome, Italy E-mail: eciprian@ uniroma3. it,... more
E-mail: gennaro. ciccarelli@ uniroma1. it, chiara. colombaroni@ uniroma1. it, gaetano. fusco@ uniroma1. it 2 Department of Civil Engineering, Roma Tre University Via Vito Volterra 62, 00139, Rome, Italy E-mail: eciprian@ uniroma3. it, sgori@ uniroma3. it, lmannini@ uniroma3. it Keywords: data fusion, probe data, Extended Kalman Filter
Abstract: Route Guidance System is a technology developed for facing efficiently traffic problems in congested urban areas. Final goals of the authors' research include the development of an Expert System prototype in order to... more
Abstract: Route Guidance System is a technology developed for facing efficiently traffic problems in congested urban areas. Final goals of the authors' research include the development of an Expert System prototype in order to simulate an on-vehicle Information System behaviour with the following characteristics:(1) route choice according to the personal user criterion;(2) capability of managing sudden critical situations (congestion, accidents, work in progress) by showing real-time alternative routes on the surrounding ...
ABSTRACT The paper deals with application of VANETs technology to road traffic monitoring and presents a distributed communication protocol, aiming at vehicular traffic monitoring. A realistic simulation of a main expressway in Roma,... more
ABSTRACT The paper deals with application of VANETs technology to road traffic monitoring and presents a distributed communication protocol, aiming at vehicular traffic monitoring. A realistic simulation of a main expressway in Roma, Italy, calibrated by exploiting information provided by a significant sample of floating car data, allows to individuate the operational limits of the communication protocols and to evaluate the accuracy of the estimates of traffic state.
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In the last years, the sensitive increase of congestion phenomena in the urban areas has produced important changes for the role reserved to the public transport. This should become the main tool to solve urban transport problem. Critical... more
In the last years, the sensitive increase of congestion phenomena in the urban areas has produced important changes for the role reserved to the public transport. This should become the main tool to solve urban transport problem. Critical phase for the planning of the public transport system is the network design problem (determination of routes and associated frequencies). This step may affect the performance of the system for the users and the successive planning steps involving the operator costs (bus and driver scheduling). In this paper, authors propose a solving procedure for the urban bus network design problem that explicitly takes into account the elasticity of the demand.
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2 Research Centre for Transport and Logistics, Sapienza University Via Eudossiana 18, 00184, Rome, Italy Ph.:+ 390644585128. Fax:+ 390644585774. E-mail: chiara. colombaroni@ uniroma1. it, gaetano. fusco@ unniroma1. it Keywords: traffic... more
2 Research Centre for Transport and Logistics, Sapienza University Via Eudossiana 18, 00184, Rome, Italy Ph.:+ 390644585128. Fax:+ 390644585774. E-mail: chiara. colombaroni@ uniroma1. it, gaetano. fusco@ unniroma1. it Keywords: traffic demand adjustment, dynamic assignment model, probe data, information reliability, SPSA
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1 BACKGROUND In the last three decades various researchers had been facing the problem of maximizing global network performances by optimizing traffic signals. The main difficulty of the problem arises from the existing interaction... more
1 BACKGROUND In the last three decades various researchers had been facing the problem of maximizing global network performances by optimizing traffic signals. The main difficulty of the problem arises from the existing interaction between network performance and users' route choice. In fact, drivers make their travel choices in order to minimize their own travel time. Simultaneous choices performed by different drivers lead to the so-called descriptive User Equilibrium (UE). As traffic controller sets signals on the basis of the observed traffic patterns, its action changes the network performance and so stimulates drivers to adjust their route choice in order to find their new minimal paths. A wide review of the scientific literature on this matter can be found in Cipriani and Gori (2000) or in Tale and Van Zuylen (2000). In the following, we deal with only some fundamentals steps, which are necessary to introduce the object of the paper. Allsop (1974) and Gartner (1974) propo...
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The paper deals with the short-term prediction of road traffic conditions within Intelligent Transportation Systems applications. First, the problem of traffic modeling and the potential of different traffic monitoring technologies are... more
The paper deals with the short-term prediction of road traffic conditions within Intelligent Transportation Systems applications. First, the problem of traffic modeling and the potential of different traffic monitoring technologies are discussed. Then, an integrated method for short-term traffic prediction is presented, which integrates an Artificial Neural Network predictor that forecasts future traffic states in standard conditions, an anomaly detection module that exploits floating car data to individuate possible occurrences of anomalous traffic conditions, and a macroscopic traffic model that predicts speeds and queue progressions in case of anomalies. Results of offline applications on a primary Italian motorway are presented. Key-Words: Intelligent Transportation Systems, Short-term traffic predictions, Neural networks, Traffic flow model, Data fusion, Incident detection
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The Scientific Seminar 2010 of the Italian Society of Transportation Scholars (SIDT) was organized within the annual international conference of the Society, which took place in Rome on the theme of the "External costs of transport... more
The Scientific Seminar 2010 of the Italian Society of Transportation Scholars (SIDT) was organized within the annual international conference of the Society, which took place in Rome on the theme of the "External costs of transport systems". This book contains a selection of the papers presented during the Scientific Seminar, which focuses on mathematical models and techniques to investigate the external costs of transport systems, including some case studies. This is the second book of SIDT proceedings written in English in order to disseminate SIDT activities to the international community. Selected papers provide an overview on the research activities of SIDT members, representing all the Italian university professors and researchers who study and teach topics in transportation, and contributing to the community debate on transport systems and related topics.
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Dealing with emergencies is never an easy task Coping with the Covid-19 emergency was and still is an incredibly tough and unprecedent challenge for mankind, not only from a healthy point of view, but also from a socio-economic point of... more
Dealing with emergencies is never an easy task Coping with the Covid-19 emergency was and still is an incredibly tough and unprecedent challenge for mankind, not only from a healthy point of view, but also from a socio-economic point of view, where a key role will be played by a reliable and sustainable transport of people and goods Professional and researchers from all disciplines have been required to adapt their models, methods and tools to support decision makers in coronavirus emergency days This paper reports the experience of the authors for the analysis of the Rome mobility system to estimate the impacts of the progressive lockdown imposed by the government It focuses on data available for monitoring, which have been used to carry out transport analytics both for private and public transport Such analytics have been used for planning the reboot of the transport system to be ready for the post Covid-19 era © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG
Massive datasets of Floating Car Data (FCD) are collected and thereafter processed to estimate and predict traffic conditions. In the framework of short-term traffic forecasting, machine learning techniques have become very popular.... more
Massive datasets of Floating Car Data (FCD) are collected and thereafter processed to estimate and predict traffic conditions. In the framework of short-term traffic forecasting, machine learning techniques have become very popular. However, the big datasets available today contain for the most part easily predictable data, that are data observed during recurrent conditions. Integration of different machine learning techniques with traffic engineering notions must contribute to obtain new transportation-oriented data-driven methods. In this paper we address traffic dynamics estimation by using individual FCD in order to develop an integrative framework able to recognize and select the suitable method for traffic forecasting. Taking into account the spatial distributions of individual FCD positions we retrieve a new spatial-based criterion for the integration of models.
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In the Intelligent Transportation Systems, integration of different components of the classical driver-vehicle-infrastructure system is supported by advances in technology and communications. This study presents a general road safety... more
In the Intelligent Transportation Systems, integration of different components of the classical driver-vehicle-infrastructure system is supported by advances in technology and communications. This study presents a general road safety analysis framework that exploits different types of data on traffic, geometry, and accidents to develop a Road Safety Analysis Center and an on-board Road Safety Driver Advisory. The Road Safety Analysis Center considers different sources of data: accident inventories, road geometry, and floating car data, which reveal drivers' behavior. Floating car data are also exploited to derive mathematically the longitudinal parameters of ancient roads, which are crucial to estimate safety conditions in curves. The critical points of the network are revealed by an aggregate analysis of accidents distribution on the roads, while the drivers' behaviour is addressed on a disaggregated level, by the evaluation of speeds distributions with a dense spatial detail. The comparison between speeds distributions, safety conditions, and accident occurrence is useful to individuate the portions of the network to be enforced with safety measures and support drivers with an advanced onboard speed advisory system. This methodology is applied to several extra-urban roads in the Latium region, Italy, to individuate roads with higher values of critical indices.
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This paper examines the impact of applying dynamic traffic assignment (DTA) and quasi-dynamic traffic assignment (QDTA) models, which apply different route choice approaches (shortest paths based on current travel times, User Equilibrium:... more
This paper examines the impact of applying dynamic traffic assignment (DTA) and quasi-dynamic traffic assignment (QDTA) models, which apply different route choice approaches (shortest paths based on current travel times, User Equilibrium: UE, and system optimum: SO), on the accuracy of the solution of the offline dynamic demand estimation problem. The evaluation scheme is based on the adoption of a bilevel approach, where the upper level consists of the adjustment of a starting demand using traffic measures and the lower level of the solution of the traffic network assignment problem. The SPSA AD-PI (Simultaneous Perturbation Stochastic Approximation Asymmetric Design Polynomial Interpolation) is adopted as a solution algorithm. A comparative analysis is conducted on a test network and the results highlight the importance of route choice model and information for the stability and the quality of the offline dynamic demand estimations.
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The object of the paper is to investigate the effect of signal synchronization on the traffic flow patterns on the network and validate results of synchronization problem in signal setting design. A platoon based traffic model is applied... more
The object of the paper is to investigate the effect of signal synchronization on the traffic flow patterns on the network and validate results of synchronization problem in signal setting design. A platoon based traffic model is applied to solve both one-way and two-way synchronization problems in under-saturated conditions. Assessment of results through dynamic traffic assignment model shows that solution found is rather robust and, if more traffic is attracted by the improved arterial performance, larger benefits can be achieved on the whole network. A specific analysis has been conducted to point out the representation of queue propagation and the gridlock phenomenon.
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Presentation of the Course Traffic Engineering and Intelligent Transportation Systems
Year 2015
Year 2015