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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.
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 StyleTullio 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 StyleTullio 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.
In the modern era, characterized by intense urbanization and frequent travel between interconnected communities, the constant expansion of cities, associated with high densities and growing need for traveling, has led to a significant increase in road traffic volumes. More than ever, road traffic today requires effort to be managed effectively in order to improve performance and safety conditions, given the greater probability of unpleasant events such as accidents or road congestion with related delays and the increased stress levels of the user and infrastructure. Fortunately, there are already various engineering tools, such as ramp metering, that can be used for this purpose. Ramp metering allows for achieving the aforementioned desired benefits, including improving mobility, reliability, efficiency, and safety, and even reducing environmental impact. It also has been shown to be cost-effective from the existing literature. Further research will be necessary to strengthen the quality, efficacy, and efficiency of ramp metering, especially considering the fast-paced progress in technology (e.g., connected autonomous vehicles and drones used for surveys) and new challenging scenarios (e.g., congested industrial areas and emergency vehicles). This review’s scope is to present a general overview of principal ramp metering solutions, focusing on current research studies in the last couple of years and highlighting some of the main algorithms used for this purpose, depending on diverse scenarios. With this article, the authors desire to present the subject of ramp metering, providing a general overview of its story, evolution, and recent analytical models.
Salvatore Trubia; Salvatore Curto; Salvatore Barberi; Alessandro Severino; Fabio Arena; Giovanni Pau. Analysis and Evaluation of Ramp Metering: From Historical Evolution to the Application of New Algorithms and Engineering Principles. Sustainability 2021, 13, 850 .
AMA StyleSalvatore Trubia, Salvatore Curto, Salvatore Barberi, Alessandro Severino, Fabio Arena, Giovanni Pau. Analysis and Evaluation of Ramp Metering: From Historical Evolution to the Application of New Algorithms and Engineering Principles. Sustainability. 2021; 13 (2):850.
Chicago/Turabian StyleSalvatore Trubia; Salvatore Curto; Salvatore Barberi; Alessandro Severino; Fabio Arena; Giovanni Pau. 2021. "Analysis and Evaluation of Ramp Metering: From Historical Evolution to the Application of New Algorithms and Engineering Principles." Sustainability 13, no. 2: 850.
Transport engineering has recently undergone several significant changes and innovations, one of which is the appearance and spread of autonomous vehicles; with this technology becoming more common and ordinary by the day, it is now necessary to implement some systems and contexts to facilitate autonomous vehicle operations. Consequently, a different perspective is now arising when dealing with road infrastructures, aiming to simplify and improve efficiency and maintenance of the existing roads, increase the life cycle of newly built ones, and minimize the economic and financial impact at the same time. Roadway pavements are one of the primary factors affecting vehicle operations; over time, this distinctive aspect has gone through various mechanical and physical changes due to the adoption of new materials or design methods. Consequently, to the spread of autonomous vehicles, scientific research has begun to study and develop systems to make road pavements and platforms not exclusively aimed at bearing loads, but rather at considering them as a means of communication and information exchange, if not even as a source of energy. This new approach introduces the so-called “Smart Roads,” i.e., road infrastructures capable of communicating with vehicles and self-monitoring fundamental perspectives concerning driverless vehicles and the roadway platform life cycle. This paper examines the characteristics of Smart Roads, considering their broad field of application and their potential advantages and drawbacks. This paper also pursues the objective of describing the global vision, the possible future direction of these innovations concerning the automotive and transport industries, and a particular focus on infrastructures and roadways.
Salvatore Trubia; Alessandro Severino; Salvatore Curto; Fabio Arena; Giovanni Pau. Smart Roads: An Overview of What Future Mobility Will Look Like. Infrastructures 2020, 5, 107 .
AMA StyleSalvatore Trubia, Alessandro Severino, Salvatore Curto, Fabio Arena, Giovanni Pau. Smart Roads: An Overview of What Future Mobility Will Look Like. Infrastructures. 2020; 5 (12):107.
Chicago/Turabian StyleSalvatore Trubia; Alessandro Severino; Salvatore Curto; Fabio Arena; Giovanni Pau. 2020. "Smart Roads: An Overview of What Future Mobility Will Look Like." Infrastructures 5, no. 12: 107.
The goal of civil engineering has always been the research and implementation of methods, technologies, and infrastructures to improve the community’s quality of life. One of the branches of civil engineering that has the strongest effect on progress is transport. The quality of transport has a profound economic and social impact on our communities regarding trade (freight transport) and city livability (public transport systems). However, innovation is not the only way to improve the features above-mentioned, especially public transport, considering that it is usually beneficial to enhance and repurpose vehicles with appropriate adjustments to offer more efficient services. Other perspectives that influence public transport systems are the costs and times of design and construction, maintenance, operating costs, and environmental impact, especially concerning CO2 emissions. Considering these issues, among the various types of existing public transport systems, those of the so-called Bus Rapid Transit (BRT) offer worthwhile results. The BRT system is a type of public road transport operated by bus on reserved lanes, and it is significantly profitable, especially from an economic point of view, in areas where there are existing bus routes. Nonetheless, for the construction of works minimization, it is closely linked to other features that improve its usefulness, depending on the vehicles’ quality such as capacity, but above all, the propulsion or driving autonomy that would guarantee high efficiency. This paper introduces an analysis of some BRT systems operating worldwide, presenting the background, general technical features, and the correlation with autonomous vehicles.
Salvatore Trubia; Alessandro Severino; Salvatore Curto; Fabio Arena; Giovanni Pau. On BRT Spread around the World: Analysis of Some Particular Cities. Infrastructures 2020, 5, 88 .
AMA StyleSalvatore Trubia, Alessandro Severino, Salvatore Curto, Fabio Arena, Giovanni Pau. On BRT Spread around the World: Analysis of Some Particular Cities. Infrastructures. 2020; 5 (10):88.
Chicago/Turabian StyleSalvatore Trubia; Alessandro Severino; Salvatore Curto; Fabio Arena; Giovanni Pau. 2020. "On BRT Spread around the World: Analysis of Some Particular Cities." Infrastructures 5, no. 10: 88.
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.
Aleksandra Deluka Tibljaš; Tullio Giuffrè; Sanja Surdonja; Salvatore Trubia. Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation. Sustainability 2018, 10, 1060 .
AMA StyleAleksandra 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 StyleAleksandra Deluka Tibljaš; Tullio Giuffrè; Sanja Surdonja; Salvatore Trubia. 2018. "Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation." Sustainability 10, no. 4: 1060.
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.
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 StyleTullio 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 StyleTullio 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.
“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.
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 StyleTullio 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 StyleTullio 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.