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Dr. TULLIO GIUFFRE'
Faculty of Engineering and Architecture, University of Enna Kore, Viale della Cooperazione, 94100 Enna, Italy

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0 statistical analysis
0 road design
0 Transport Infrastructure
0 Road safety evaluation
0 Connected automated vehicles operations

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Journal article
Published: 06 August 2021 in Sustainability
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The paper presents a microsimulation approach for assessing the safety performance of turbo-roundabouts where Cooperative Autonomous Vehicles “CAVs” have been introduced into the traffic mix alongside conventional vehicles “CVs”. Based on the analysis of vehicle trajectories from VISSIM and subsequent analysis of traffic conflicts through the Surrogate Safety Assessment Model (SSAM), the research aims to evaluate the safety benefits of turbo-roundabouts where the lanes are physically separated by raised curbs, compared to roundabouts without such curbs. The paper will then describe the methodological path followed to build VISSIM models of turbo-roundabouts with and without raised curbs in order to calibrate the simulation models and estimate the potential conflicts when a higher percentage of CAVs are introduced into the traffic mix. A criterion has been also proposed for setting properly the principal SSAM filters. The results confirmed both higher safety levels for turbo-roundabouts equipped with raised lane dividers compared to turbo-roundabout solutions without curbs, and better safety conditions under the traffic mix of CVs and CAVs. Therefore, it follows that, in absence of crash data including CAVs, the surrogate measures of safety are the only approach in which the safety performance of any roundabout or road entity can be evaluated.

ACS Style

Tullio Giuffrè; Anna Granà; Salvatore Trubia. Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation. Sustainability 2021, 13, 8810 .

AMA Style

Tullio Giuffrè, Anna Granà, Salvatore Trubia. Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation. Sustainability. 2021; 13 (16):8810.

Chicago/Turabian Style

Tullio Giuffrè; Anna Granà; Salvatore Trubia. 2021. "Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation." Sustainability 13, no. 16: 8810.

Journal article
Published: 20 February 2021 in Infrastructures
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Generally, during maintenance operations on bridges and motorway viaducts, the circulation of vehicles is limited or suspended. This causes significant economic losses due to the increase in the costs of transport: delays, increased fuel consumption, higher emissions of pollutants into the atmosphere, increased risk of accidents, etc. However, few studies have analyzed the influence of bridge vibrations on the final mechanical properties of the cement mortar placing during ordinary bridge service. As such, interest is increasing in repair techniques that could achieve high structural performance without reducing road service levels. This paper provides the results obtained through an innovative laboratory trials campaign that evaluated the influence of vibrations on the mechanical properties of high-performance mortar used for repairing bridge decks. The results of 24 cubic and prismatic specimens showed the relationship between the traffic-induced vibrations and the mechanical characteristics of the studied mortar. The findings can be considered as the first methodologic step that is necessary to address further field studies, drawing a detailed link between the repair techniques and transportation user costs. Based on the obtained results, a synthetic bridge management system framework was developed that merges the road function into the structural issue with the goals of increasing the resilience of road networks and optimizing the maintenance resources budget.

ACS Style

Tullio Giuffrè; Marinella Fossetti; Alfio Siciliano. A New Experimental Investigation for Improving Bridge Management Systems and Road Operation Sustainability. Infrastructures 2021, 6, 31 .

AMA Style

Tullio Giuffrè, Marinella Fossetti, Alfio Siciliano. A New Experimental Investigation for Improving Bridge Management Systems and Road Operation Sustainability. Infrastructures. 2021; 6 (2):31.

Chicago/Turabian Style

Tullio Giuffrè; Marinella Fossetti; Alfio Siciliano. 2021. "A New Experimental Investigation for Improving Bridge Management Systems and Road Operation Sustainability." Infrastructures 6, no. 2: 31.

Research article
Published: 05 December 2018 in Journal of Advanced Transportation
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The paper presents a microsimulation-based approach for roundabout safety performance evaluation. Based on a sample of Slovenian roundabouts, the vehicle trajectories exported from AIMSUN and VISSIM were used to estimate traffic conflicts using the Surrogate Safety Assessment Model (SSAM). AIMSUN and VISSIM were calibrated for single-lane, double-lane and turbo roundabouts using the corresponding empirical capacity function which included critical and follow-up headways estimated through meta-analysis. Based on calibration of the microsimulation models, a crash prediction model from simulated peak hour conflicts for a sample of Slovenian roundabouts was developed. A generalized linear model framework was used to estimate the prediction model based on field collected crash data for 26 existing roundabouts across the country. Peak hour traffic distribution was simulated with AIMSUN, and peak hour conflicts were then estimated with the SSAM applying the filters identified by calibrating AIMSUN and VISSIM. The crash prediction model was based on the assumption that the crashes per year are a function of peak hour conflicts, the ratio of peak hour traffic volume to average daily traffic volume and the roundabout outer diameter. Goodness-of-fit criteria highlighted how well the model fitted the set of observations also better than the SSAM predictive model. The results highlighted that the safety assessment of any road unit may rely on surrogate safety measures, but it strongly depends on microscopic traffic simulation model used.

ACS Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Tullio Giuffrè; Salvatore Trubia; Antonino Sferlazza; Marko Rencelj. Evaluation of Roundabout Safety Performance through Surrogate Safety Measures from Microsimulation. Journal of Advanced Transportation 2018, 2018, 1 -14.

AMA Style

Orazio Giuffrè, Anna Granà, Maria Luisa Tumminello, Tullio Giuffrè, Salvatore Trubia, Antonino Sferlazza, Marko Rencelj. Evaluation of Roundabout Safety Performance through Surrogate Safety Measures from Microsimulation. Journal of Advanced Transportation. 2018; 2018 ():1-14.

Chicago/Turabian Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Tullio Giuffrè; Salvatore Trubia; Antonino Sferlazza; Marko Rencelj. 2018. "Evaluation of Roundabout Safety Performance through Surrogate Safety Measures from Microsimulation." Journal of Advanced Transportation 2018, no. : 1-14.

Journal article
Published: 26 August 2018 in Journal of Intelligent & Fuzzy Systems
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ACS Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Antonino Sferlazza. Calibrating a microscopic traffic simulation model for roundabouts using genetic algorithms. Journal of Intelligent & Fuzzy Systems 2018, 35, 1791 -1806.

AMA Style

Orazio Giuffrè, Anna Granà, Maria Luisa Tumminello, Antonino Sferlazza. Calibrating a microscopic traffic simulation model for roundabouts using genetic algorithms. Journal of Intelligent & Fuzzy Systems. 2018; 35 (2):1791-1806.

Chicago/Turabian Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Antonino Sferlazza. 2018. "Calibrating a microscopic traffic simulation model for roundabouts using genetic algorithms." Journal of Intelligent & Fuzzy Systems 35, no. 2: 1791-1806.

Conference paper
Published: 01 August 2018 in Roundabouts as Safe and Modern Solutions in Transport Networks and Systems
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This paper addresses issues on road safety analysis through microscopic traffic simulation models. The Surrogate Safety Assessment Model (SSAM) was applied to read vehicle trajectory files generated by two micro-simulators and then calculate surrogate measures of safety. Since safety assessment of any road entity can provide different results based on the micro-simulator which is used, the main objective of this research was to estimate the safety performance of three roundabout layouts and compare the conflict events simulated by AIMSUN and VISSIM. The two micro-simulators were used to build the calibrated models of the roundabouts, each fitting the corresponding empirical capacity function. The results provided insights on how to set the SSAM filters in order to have a comparable frequency of conflicts by simulation and examine conditions under which a safety analysis could be independent of the software used.

ACS Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Tullio Giuffrè; Salvatore Trubia. Surrogate Measures of Safety at Roundabouts in AIMSUN and VISSIM Environment. Roundabouts as Safe and Modern Solutions in Transport Networks and Systems 2018, 53 -64.

AMA Style

Orazio Giuffrè, Anna Granà, Maria Luisa Tumminello, Tullio Giuffrè, Salvatore Trubia. Surrogate Measures of Safety at Roundabouts in AIMSUN and VISSIM Environment. Roundabouts as Safe and Modern Solutions in Transport Networks and Systems. 2018; ():53-64.

Chicago/Turabian Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Tullio Giuffrè; Salvatore Trubia. 2018. "Surrogate Measures of Safety at Roundabouts in AIMSUN and VISSIM Environment." Roundabouts as Safe and Modern Solutions in Transport Networks and Systems , no. : 53-64.

Journal article
Published: 16 April 2018 in Materials
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In the last forty, years semi-flexible pavements have been successfully employed, especially in those areas subjected to heavy and slow-moving loads. They usually comprise a wearing course of Grouted Macadam, a composite pavement material that provides significant advantages in comparison to both concrete and asphalt pavements. On the other hand, the laying process of this material is a two-stage operation, and the realization complexity leads to long realization times and high initial costs. Therefore, the use of semi-flexible pavements has been limited to some fields of application and areas. Recently, an innovative material has been developed to be used as an alternative to Grouted Macadam for semi-flexible pavement wearing course realization. This material should provide similar or even superior characteristics compared to traditional Grouted Macadam. This will reduce semi-flexible pavement construction time and avoid the need for dividing the laying process. This paper presents an experimental program involving the use of FastFWD, as an APT device, to evaluate in-situ properties and performance of this material. The achieved results regarding the validation of this new material by means of FastFWD appear promising both in terms of the material’s properties and resistance to dynamic load repetitions.

ACS Style

Chiara Pratelli; Giacomo Betti; Tullio Giuffrè; Alessandro Marradi. Preliminary In-Situ Evaluation of an Innovative, Semi-Flexible Pavement Wearing Course Mixture Using Fast Falling Weight Deflectometer. Materials 2018, 11, 611 .

AMA Style

Chiara Pratelli, Giacomo Betti, Tullio Giuffrè, Alessandro Marradi. Preliminary In-Situ Evaluation of an Innovative, Semi-Flexible Pavement Wearing Course Mixture Using Fast Falling Weight Deflectometer. Materials. 2018; 11 (4):611.

Chicago/Turabian Style

Chiara Pratelli; Giacomo Betti; Tullio Giuffrè; Alessandro Marradi. 2018. "Preliminary In-Situ Evaluation of an Innovative, Semi-Flexible Pavement Wearing Course Mixture Using Fast Falling Weight Deflectometer." Materials 11, no. 4: 611.

Journal article
Published: 03 April 2018 in Sustainability
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Driving experiences provided by the introduction of new vehicle technologies are directly impacting the criteria for road network design. New criteria should be taken into consideration by designers, researchers and car owners in order to assure traffic safety in changed conditions that will appear with, for example, introduction of Autonomous Vehicles (AVs) in everyday traffic. In this paper, roundabout safety level is analysed on the originally developed microsimulation model in circumstances where different numbers of AVs vehicles are mixed with Conventional Vehicles (CVs). Field data about speed and traffic volumes from existing roundabouts in Croatia were used for development of the model. The simulations done with the Surrogate Safety Assessment Model (SSAM) give some relevant highlights on how the introduction of AVs could change both operational and safety parameters at roundabouts. To further explore the effects on safety of roundabouts with the introduction of different shares of AVs, hypothetical safety treatments could be tested to explore whether their effects may change, leading to the estimation of a new set of Crash Modification Factors.

ACS Style

Aleksandra Deluka Tibljaš; Tullio Giuffrè; Sanja Surdonja; Salvatore Trubia. Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation. Sustainability 2018, 10, 1060 .

AMA Style

Aleksandra Deluka Tibljaš, Tullio Giuffrè, Sanja Surdonja, Salvatore Trubia. Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation. Sustainability. 2018; 10 (4):1060.

Chicago/Turabian Style

Aleksandra Deluka Tibljaš; Tullio Giuffrè; Sanja Surdonja; Salvatore Trubia. 2018. "Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation." Sustainability 10, no. 4: 1060.

Journal article
Published: 27 February 2018 in Sustainability
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Nowadays, one important challenge is to demonstrate an innovative and integrated approach for the sustainable construction of roads considering the whole life cycle of the infrastructure. Road pavements with multiple asphalt layers generally undergo prolonged environmental exposure and the alternation between solar irradiation and low temperatures. As a result, relaxation or progressive removal of the material with a negative impact on the resistance to plastic deformation occur, also leading to the formation of slits and to dimensional variations, which are commonly defined as thermal cracking. This suggests the use of suitable bitumen modifiers. For these, important parameters are the optimal mixing time and mixing temperature, in order to reduce problems related to the stability of the bitumen. Therefore, the behaviour, upon changing the temperature, of bituminous mixtures containing (as fillers) a series of metal oxides coming, as secondary products, from spent acid solutions regeneration processes, was investigated. This is intended in order to recover and reuse those otherwise dangerous wastes coming from several industrial (especially, metallurgical) processes. The study was aimed at evaluating the properties of bituminous blends by performing rheological tests under dynamic shear regime. More specifically, five different bitumen matrices were prepared (70/100 bitumen and blends with metal oxides and/or SBS copolymer). Results showed that the addition of iron oxides leads to an increase of the softening point and the complex modulus. The increase is even more emphasized when SBS is added to the blend.

ACS Style

Tullio Giuffrè; Marco Morreale; Giovanni Tesoriere; Salvatore Trubia. Rheological Behaviour of a Bitumen Modified with Metal Oxides Obtained by Regeneration Processes. Sustainability 2018, 10, 604 .

AMA Style

Tullio Giuffrè, Marco Morreale, Giovanni Tesoriere, Salvatore Trubia. Rheological Behaviour of a Bitumen Modified with Metal Oxides Obtained by Regeneration Processes. Sustainability. 2018; 10 (3):604.

Chicago/Turabian Style

Tullio Giuffrè; Marco Morreale; Giovanni Tesoriere; Salvatore Trubia. 2018. "Rheological Behaviour of a Bitumen Modified with Metal Oxides Obtained by Regeneration Processes." Sustainability 10, no. 3: 604.

Journal article
Published: 01 February 2018 in Simulation Modelling Practice and Theory
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ACS Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Antonino Sferlazza. Capacity-based calculation of passenger car equivalents using traffic simulation at double-lane roundabouts. Simulation Modelling Practice and Theory 2018, 81, 11 -30.

AMA Style

Orazio Giuffrè, Anna Granà, Maria Luisa Tumminello, Antonino Sferlazza. Capacity-based calculation of passenger car equivalents using traffic simulation at double-lane roundabouts. Simulation Modelling Practice and Theory. 2018; 81 ():11-30.

Chicago/Turabian Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Antonino Sferlazza. 2018. "Capacity-based calculation of passenger car equivalents using traffic simulation at double-lane roundabouts." Simulation Modelling Practice and Theory 81, no. : 11-30.

Journal article
Published: 13 November 2017 in Sustainability
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“Standard” roundabouts, for example those designed in some European countries, can often be characterized by low levels of safety or capacity and a high degree of sustainability. Given the proliferation of newer layouts, it is of interest to explore whether design practices could be improved by capitalizing on the experience gained internationally. Operational aspects of some of these designs have been explored previously, but there is a need to compare both the operational and safety performance of new designs to that of standard roundabouts. The objective of this paper is to evaluate the safety and operational implications of various potential alternatives to the standard roundabouts that proliferate in Europe and elsewhere. Microsimulation is used to simulate traffic operations at roundabout layout alternatives at the same levels of volume to capacity (V/C) ratio and also with the same traffic flow. Operational performance measures include the common level of service parameters, while measures of safety are based initially on time to collision (TTC) values. Threshold values of TTC were then applied in defining conflicts that are used for crash-based safety evaluation by applying crash-conflict models estimated in published research. Interesting insights were revealed, suggesting that the newer layouts should be considered where warranted by cost-benefit considerations.

ACS Style

Tullio Giuffrè; Salvatore Trubia; Antonino Canale; Bhagwant Persaud. Using Microsimulation to Evaluate Safety and Operational Implications of Newer Roundabout Layouts for European Road Networks. Sustainability 2017, 9, 2084 .

AMA Style

Tullio Giuffrè, Salvatore Trubia, Antonino Canale, Bhagwant Persaud. Using Microsimulation to Evaluate Safety and Operational Implications of Newer Roundabout Layouts for European Road Networks. Sustainability. 2017; 9 (11):2084.

Chicago/Turabian Style

Tullio Giuffrè; Salvatore Trubia; Antonino Canale; Bhagwant Persaud. 2017. "Using Microsimulation to Evaluate Safety and Operational Implications of Newer Roundabout Layouts for European Road Networks." Sustainability 9, no. 11: 2084.

Journal article
Published: 01 August 2017 in Expert Systems with Applications
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ACS Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Antonino Sferlazza. Estimation of Passenger Car Equivalents for single-lane roundabouts using a microsimulation-based procedure. Expert Systems with Applications 2017, 79, 333 -347.

AMA Style

Orazio Giuffrè, Anna Granà, Maria Luisa Tumminello, Antonino Sferlazza. Estimation of Passenger Car Equivalents for single-lane roundabouts using a microsimulation-based procedure. Expert Systems with Applications. 2017; 79 ():333-347.

Chicago/Turabian Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello; Antonino Sferlazza. 2017. "Estimation of Passenger Car Equivalents for single-lane roundabouts using a microsimulation-based procedure." Expert Systems with Applications 79, no. : 333-347.

Original paper
Published: 30 March 2017 in European Transport Research Review
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In gap-acceptance theory the critical and the follow-up headways have a significant role in determining roundabout entry capacities which in turn depend on circulating flow rates under a specified arrival headway distribution. Calculation considers single mean values of the gap-acceptance parameters, neglecting the inherent variations in these random variables and providing a single value of entry capacity. The purpose of this paper is to derive the entry capacity distribution which accounts for the variations of the contributing (random) variables and suggest how to consider this issue in the operational analysis of the roundabouts. We performed a Monte Carlo simulation to get the distribution of entry capacity and found Crystal Ball software effective for performing the random sampling from the probability density functions of each contributing parameter. A steady-state model of capacity was used for performing many runs; in each run, the values of each contributing parameter were randomly drawn from the corresponding distributions. The paper presents the first simulations and the entry capacity distributions at roundabouts, once the probability distributions of the headways were assumed. The results of the analysis were expressed probabilistically, meaning that the probability distributions of capacity rather than the simple point estimates were obtained. Comparing the capacity values based on a meta-analytic estimation of critical and follow-up headways and the capacity functions based on the probability distributions of the model parameters, more insights in developing an appropriate approach to capacity estimation at roundabouts can be gained.

ACS Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello. Exploring the uncertainty in capacity estimation at roundabouts. European Transport Research Review 2017, 9, 18 .

AMA Style

Orazio Giuffrè, Anna Granà, Maria Luisa Tumminello. Exploring the uncertainty in capacity estimation at roundabouts. European Transport Research Review. 2017; 9 (2):18.

Chicago/Turabian Style

Orazio Giuffrè; Anna Granà; Maria Luisa Tumminello. 2017. "Exploring the uncertainty in capacity estimation at roundabouts." European Transport Research Review 9, no. 2: 18.

Journal article
Published: 28 June 2016 in Transport
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Due to its geometric design, turbo-roundabouts impose greatest constraints to the vehicular trajectories; by consequence, one can expect a more unfavourable impact of heavy vehicles on the traffic conditions than on other types of roundabouts. The present paper addresses the question of how to estimate Passenger Car Equivalents (PCEs) for heavy vehicles driving turbo-roundabouts. The microsimulation approach used revealed as a useful tool for evaluating the variation of quality of traffic in presence of mixed fleets (different percentages of heavy vehicles). Based on the output of multiple runs of several scenarios simulation, capacity functions for each entry lane of the turbo-roundabout were developed and variability of the PCEs for heavy vehicles were calculated by comparing results for a fleet of passenger cars only with those of the mixed fleet scenarios. Results show a dependence of PCEs for heavy vehicles on operational conditions, which characterise the turbo-roundabout. Assuming the values of PCEs for roundabouts provided by the 2010 Highway Capacity Manual (HCM), depending on entering manoeuvring underestimation and overestimation of the effect of heavy vehicles on the quality of traffic conditions have been found.

ACS Style

Orazio Giuffre'; Anna Granà; Sergio Marino; Fabio Galatioto. MICROSIMULATION-BASED PASSENGER CAR EQUIVALENTS FOR HEAVY VEHICLES DRIVING TURBO-ROUNDABOUTS. Transport 2016, 31, 295 -303.

AMA Style

Orazio Giuffre', Anna Granà, Sergio Marino, Fabio Galatioto. MICROSIMULATION-BASED PASSENGER CAR EQUIVALENTS FOR HEAVY VEHICLES DRIVING TURBO-ROUNDABOUTS. Transport. 2016; 31 (2):295-303.

Chicago/Turabian Style

Orazio Giuffre'; Anna Granà; Sergio Marino; Fabio Galatioto. 2016. "MICROSIMULATION-BASED PASSENGER CAR EQUIVALENTS FOR HEAVY VEHICLES DRIVING TURBO-ROUNDABOUTS." Transport 31, no. 2: 295-303.

Journal article
Published: 01 February 2016 in Expert Systems with Applications
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This paper presents the first results of a research which applied a genetic algorithm to calibrate a microscopic traffic simulation model based on speed-density relationships. A large set of traffic data collected from the A22 Freeway, Italy, was used and a comparison was performed between the field measurements and the simulation outputs obtained for a test freeway segment by using the Aimsun microscopic simulator. The calibration was formulated as an optimization problem to be solved based on a genetic algorithm; the objective function was defined in order to minimize the differences between the simulated and real data sets in the speed-density graphs. For this purpose, the genetic algorithm tool in MATLAB®was applied. Keeping in mind the objective to automatize this process, the optimization technique was attached to Aimsun via a subroutine, so that the data transfer between the two programs could automatically happen. An external script written in Python allowed the MATLAB®software to interact with Aimsun software. A better match to the field data was reached with the optimization parameters set with the genetic algorithm. In order to check to what extent the model replicated reality, model validation was also addressed. Results showed that a genetic algorithm is usefully applicable in the calibration process of the microscopic traffic simulation model. Beneficial effects are expected by applying the suggested optimization technique since it searches for an optimum set of parameters through an efficient search method

ACS Style

Sandro Chiappone; Orazio Giuffre'; Anna Granà; Raffaele Mauro; Antonino Sferlazza. Traffic simulation models calibration using speed–density relationship: An automated procedure based on genetic algorithm. Expert Systems with Applications 2016, 44, 147 -155.

AMA Style

Sandro Chiappone, Orazio Giuffre', Anna Granà, Raffaele Mauro, Antonino Sferlazza. Traffic simulation models calibration using speed–density relationship: An automated procedure based on genetic algorithm. Expert Systems with Applications. 2016; 44 ():147-155.

Chicago/Turabian Style

Sandro Chiappone; Orazio Giuffre'; Anna Granà; Raffaele Mauro; Antonino Sferlazza. 2016. "Traffic simulation models calibration using speed–density relationship: An automated procedure based on genetic algorithm." Expert Systems with Applications 44, no. : 147-155.

Journal article
Published: 01 January 2016 in Transportation Research Procedia
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Turbo-roundabouts represent an innovative scheme of modern roundabouts which provides a spiraling traffic flow and requires drivers to choose their direction before entering the intersection, since raised lane separators mark the lanes on the ring. The configuration of the turbo-roundabout makes that patterns of conflict at entries with one and two conflicting traffic streams can coexist.This paper presents research efforts aimed at measuring quantitatively the effect of heavy vehicles on operational conditions of a turbo-roundabout. The study starts from the initial belief that the greatest constraints to the vehicular trajectories imposed by the turbo-roundabout necessarily imply that the impact of heavy vehicles on the quality of traffic flow is more unfavorable than on other modern roundabouts. Microsimulation revealed as a useful tool when the variation of the traffic quality in turbo-roundabouts should be evaluated in presence of mixed fleets, each having different percentages of heavy vehicles; indeed, it allowed to isolate traffic conditions difficult to observe on field and replicate them to have a number of data as much as possible numerous. Entry capacity values for each entry lane of the turbo-roundabout were obtained by microsimulation, varying the percentage of heavy vehicles for entering flows. Nonlinear regression analysis of simulation data allowed to derive the behavioral parameters for heterogeneous populations of users and, ultimately, composed exclusively of heavy vehicles. The capacity functions thus obtained allowed us to determine how the passenger car equivalent (PCE) varies with the percentage of heavy vehicles and circulating flows for each entry lane of the turbo-roundabout. The results of this study indicate that there is a need to distinguish the impact of heavy vehicles when analyzing the capacity of a turbo-roundabout. When the traffic stream contains a significant number of heavy vehicles, a larger PCE effect would be expected. This effect should be accounted for in the estimation of the turbo-roundabout capacity. Lastly it should be emphasized that an important aspect of the research consists in having identified a methodology for assessing the impact of heavy vehicles on the quality of traffic flow, that can be applied to different patterns of intersection.

ACS Style

Orazio Giuffrè; Anna Grana; Sergio Marino; Fabio Galatioto. Passenger Car Equivalent for Heavy Vehicles Crossing Turbo-roundabouts. Transportation Research Procedia 2016, 14, 4190 -4199.

AMA Style

Orazio Giuffrè, Anna Grana, Sergio Marino, Fabio Galatioto. Passenger Car Equivalent for Heavy Vehicles Crossing Turbo-roundabouts. Transportation Research Procedia. 2016; 14 ():4190-4199.

Chicago/Turabian Style

Orazio Giuffrè; Anna Grana; Sergio Marino; Fabio Galatioto. 2016. "Passenger Car Equivalent for Heavy Vehicles Crossing Turbo-roundabouts." Transportation Research Procedia 14, no. : 4190-4199.

Review
Published: 07 December 2015 in European Transport Research Review
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The critical and follow-up headways are the two gap-acceptance parameters which explain the traffic interaction of a minor street vehicle when enters the roundabout, merging into or crossing one or more circulating (major) streams. Several studies and researches provide measurements of critical and follow-up headways from real data at roundabouts. The objective of our research is to synthesize the data from the series of selected studies to interpret variation across the studies. In order to match the research goal, a systematic literature review on estimations of critical and follow-up headways at roundabouts was undertaken. Since several studies and researches developed worldwide were examined, we were able to note that the effect size varied from study to study. Thus the meta-analysis of effect sizes was performed as part of the literature review through the random-effects model. After discussing the assumptions of this model, the dispersion in effects across studies was assessed and the summary effect for each of the parameters under examination was computed. Calculations were made both for single-lane roundabouts and double-lane roundabouts, as well as for turbo roundabouts. Compared to the results of individual studies, the single (quantitative) meta-analytic estimate provides an accurate and reliable synthesis on the specific issue here addressed, and gives, with greater power of the individual reviewed studies, a comprehensive measure for the parameters of interest.

ACS Style

Orazio Giuffre'; Anna Granà; Maria Luisa Tumminello. Gap-accepteance parameters for roundabouts: a systematic review. European Transport Research Review 2015, 8, 1 -20.

AMA Style

Orazio Giuffre', Anna Granà, Maria Luisa Tumminello. Gap-accepteance parameters for roundabouts: a systematic review. European Transport Research Review. 2015; 8 (1):1-20.

Chicago/Turabian Style

Orazio Giuffre'; Anna Granà; Maria Luisa Tumminello. 2015. "Gap-accepteance parameters for roundabouts: a systematic review." European Transport Research Review 8, no. 1: 1-20.

Journal article
Published: 01 January 2015 in Transportation Research Procedia
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In this paper a method of estimation of the passenger car equivalents for heavy vehicles on freeway is described. The variation in traffic quality was evaluated basing on a traffic demand characterized by different percentages of heavy vehicles. Aimsun micro-simulator was used to isolate traffic conditions difficult to capture on field, to replicate them to have a number of data as much as possible numerous, and to quantify the fundamental variables of traffic flow, namely the speed, flow, density, for a test freeway segment. Model calibration was accomplished by using traffic data collected at observation sections on the A22 Brenner Freeway, Italy. In order to check to what extent the model replicated reality, the validation of the calibrated model was also addressed. Simulation data were used to develop the relationships among the variables of traffic flow and to calculate the passenger car equivalents for heavy vehicles by comparing a fleet of passenger cars only with a mixed fleet characterized every time by different percentages of heavy vehicles. Despite the exploratory nature of this study, some implications can be drawn: PCE estimations are small at low flow rates and increase with increased flow rates due to at low volumes there are few passenger cars that can be influenced by heavy vehicles.

ACS Style

Orazio Giuffre'; Anna Granà; Raffaele Mauro; Ana Bastos Silva; Sandro Chiappone. Developing Passenger Car Equivalents for Freeways by Microsimulation. Transportation Research Procedia 2015, 10, 93 -102.

AMA Style

Orazio Giuffre', Anna Granà, Raffaele Mauro, Ana Bastos Silva, Sandro Chiappone. Developing Passenger Car Equivalents for Freeways by Microsimulation. Transportation Research Procedia. 2015; 10 ():93-102.

Chicago/Turabian Style

Orazio Giuffre'; Anna Granà; Raffaele Mauro; Ana Bastos Silva; Sandro Chiappone. 2015. "Developing Passenger Car Equivalents for Freeways by Microsimulation." Transportation Research Procedia 10, no. : 93-102.

Journal article
Published: 01 September 2014 in Archives of Civil Engineering
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In the paper, a choice criterion between flower roundabouts and double-lane roundabouts is proposed, focusing on operational benefits that can derive from one scheme over the other, and outlining a general framework for benefit-cost analysis. In order to assess operational benefits of innovative roundabouts over modern roundabouts, a comparative analysis was made. Capacity was estimated using gap-acceptance models. In detail, assuming the dichotomic shifted negative exponential distribution to model headways in circulating streams, the Hagring formula was adjusted to obtain entry capacity estimations at roundabout approaches where entering vehicles face one or two conflicting flows. Based on the control delay, the suitability domains and indifference areas were constructed. Thus, a sensitivity analysis to changes in traffic demand for operational benefits of flower roundabouts over double-lane roundabouts was carried out and discussed. At last, evidence for new installations and conversion of existing roundabouts can be found.

ACS Style

Tullio Giuffre'; Anna Grana; Roberta Marino; S. Marino. Flower Roundabouts And Double-Lane Roundabouts: A Comparative Performance Analysis. Archives of Civil Engineering 2014, 60, 349 -365.

AMA Style

Tullio Giuffre', Anna Grana, Roberta Marino, S. Marino. Flower Roundabouts And Double-Lane Roundabouts: A Comparative Performance Analysis. Archives of Civil Engineering. 2014; 60 (3):349-365.

Chicago/Turabian Style

Tullio Giuffre'; Anna Grana; Roberta Marino; S. Marino. 2014. "Flower Roundabouts And Double-Lane Roundabouts: A Comparative Performance Analysis." Archives of Civil Engineering 60, no. 3: 349-365.

Article
Published: 01 August 2014 in IET Intelligent Transport Systems
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Parking is becoming an expensive resource in almost any major city in the world, and its limited availability is a concurrent cause of urban traffic congestion, and air pollution. In old cities, the structure of the public parking space is rigidly organised and often in the form of on-street public parking spots. Unfortunately, these public parking spots cannot be reserved beforehand during the pre-trip phase, and that often lead to a detriment of the quality of urban mobility. Addressing the problem of managing public parking spots is therefore vital to obtain environmentally friendlier and healthier cities. Recent technological progresses in industrial automation, wireless network, sensor communication along with the widespread of high-range smart devices and new rules concerning financial transactions in mobile payment allow the definition of new intelligent frameworks that enable a convenient management of public parking in urban area, which could improve sustainable urban mobility. In such a scenario, the proposed intelligent parking assistant (IPA) architecture aims at overcoming current public parking management solutions. This study discusses the conceptual architecture of IPA and the first prototype-scale simulations of the system.

ACS Style

Rosamaria Elisa Barone; Tullio Giuffrè; Sabato Marco Siniscalchi; Maria Antonietta Morgano; Giovanni Tesoriere. Architecture for parking management in smart cities. IET Intelligent Transport Systems 2014, 8, 445 -452.

AMA Style

Rosamaria Elisa Barone, Tullio Giuffrè, Sabato Marco Siniscalchi, Maria Antonietta Morgano, Giovanni Tesoriere. Architecture for parking management in smart cities. IET Intelligent Transport Systems. 2014; 8 (5):445-452.

Chicago/Turabian Style

Rosamaria Elisa Barone; Tullio Giuffrè; Sabato Marco Siniscalchi; Maria Antonietta Morgano; Giovanni Tesoriere. 2014. "Architecture for parking management in smart cities." IET Intelligent Transport Systems 8, no. 5: 445-452.

Journal article
Published: 01 March 2014 in Archives of Civil Engineering
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Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006-2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In order to account for the correlation within responses Generalized Estimating Equations (GEE) were used under different working correlation matrices.

ACS Style

Tullio Giuffre'; Anna Granà; R A Marino; S. Marino. Estimating the Safety Performance Function for Urban Unsignalized Four-Legged One-Way Intersections in Palermo, Italy. Archives of Civil Engineering 2014, 60, 41 -54.

AMA Style

Tullio Giuffre', Anna Granà, R A Marino, S. Marino. Estimating the Safety Performance Function for Urban Unsignalized Four-Legged One-Way Intersections in Palermo, Italy. Archives of Civil Engineering. 2014; 60 (1):41-54.

Chicago/Turabian Style

Tullio Giuffre'; Anna Granà; R A Marino; S. Marino. 2014. "Estimating the Safety Performance Function for Urban Unsignalized Four-Legged One-Way Intersections in Palermo, Italy." Archives of Civil Engineering 60, no. 1: 41-54.