Francesco Saverio Capaldo | Università degli Studi di Napoli "Federico II" (original) (raw)
Papers by Francesco Saverio Capaldo
The traffic light coordination is often considered as a measure to improve traffic speed by reduc... more The traffic light coordination is often considered as a measure to improve traffic speed by reducing car emissions per meter. Although the dynamic approach has been widely developed in theory and application, the static approach can be still useful in many design problems. Often design is made by static approaches and is also verified with dynamic models. The static approach studied in this paper starts from flow profiles of vehicle platoons departing from a traffic light. Several past studies have been concerned with the definition of flow profiles and in this paper it considers modeling with the collected data by using the approach of cyclic flow profiles (TRANSYT TRRL) which gives the arrival distribution of flow platoons as a function of the distance from the first intersection through a recurrent computation. It can know the car number that is in late for the green phase at the second light and then decide to increase the second green time according to the access waiting time o...
This paper analyzes the problem of the inclusion of road infrastructure in the present environmen... more This paper analyzes the problem of the inclusion of road infrastructure in the present environment; in fact many international and national studies and research have been carried out to address this aspect of road infrastructure construction. Although many approaches to this type of problem exist, now there are two main procedures to solve it: a) the surrounding environment seen from the road (i.e. from the perspective of the driver's eye), and b) the whole surrounding environment observed from off the road (the point of view external to the road). The experimental analysis presented here shows a predictive model to assess the beauty of a scenario in which the road is introduced from the road. The model has been developed thanks to experimental investigation using a sample of 200 non-expert judges asked to express an opinion on 32 different scenes in conventional photographs selected from low-volume roads within the Province of Salerno. The coefficients of the resulting model ha...
The increase in traffic flows on the roads causes an increase in road accidents. The study of the... more The increase in traffic flows on the roads causes an increase in road accidents. The study of the road safety deals on how to reduce the related phenomenon to non-pathological levels; to be able to operate correctly, much different information are needed. For some different levels of investigation of the phenomenon, only the incidental statistics may be necessary. To plan the interventions it needs information on the single incidents that occur in some areas. Each incident has some evolution characteristics that are repeated in a non-random manner, and these recurrences must be highlighted and studied to obtain effective countermeasures. The study methodologies of the road accidents maybe not only on their typology and imply the possibility of reconstruction, even if approximate, of the incident and its temporal phases of development. In some cases, it may also be necessary to evaluate the impact speed between vehicles. Some incident reconstruction techniques allow obtaining reliabl...
The Linear Scheduling Method (LSM) is the most effective scheduling tool to use in linear project... more The Linear Scheduling Method (LSM) is the most effective scheduling tool to use in linear projects. Computer programs have been developed for various scheduling techniques such as Bar Chart, PERT and CPM. There are not many commercially available toolkit for LSM and this lack of toolkit is one of the reasons for its limited usage. The product of this research is a toolkit comprised of models, procedures and tools that allow for implementation of the linear scheduling method. This toolkit is able to calculate the controlling activity path of such schedules, to level the resources of a project scheduled and to print reports of the status of the schedule. The paper describes the toolkit that was developed by the research, its documentation and example for an Italian case study that was scheduled using this prototype.
The traffic light coordination is often considered as a measure to improve traffic speed reducing... more The traffic light coordination is often considered as a measure to improve traffic speed reducing car emission per meter. Although the dynamic approach has been widely developed in theory and application, static approach can be still useful in many design problems. Often design is made by static approaches and is also verified with dynamic models. The static approach study, in this paper, starts from flow profiles of vehicle platoons departing from a traffic light. Several past studies have concerned on the definition of flow profiles and in this paper it considers the collecting data modeling using the approach of cyclic flow profiles (TRANSYT TRRL) who gives the arrival distribution of flow platoons as a function of the distance from the first intersection through a recurrent computing. So it can know the car number in late for the green phase at the second light and then decide to increase the second green time according to the access waiting time or, conversely, reduce the green...
Transportation Research Procedia
Transportation Research Procedia
A survey for road safety must draw on a wide range of data, for the technician or researcher it i... more A survey for road safety must draw on a wide range of data, for the technician or researcher it is important to be able to access the databases organized and up to date. These data concern sure the incidents, the study area demographics, the current infrastructure data, traffic flows, but other data relate to different study problems. Without well organized bases the collection and analysis of data becomes an expensive phase that can and should be carried out, depending on the available resources, to a different levels of detail. Various levels of detail require the acquisition of different kinds of data. Their treatment may provide different indexes and accidents ratio that can bring different interpretations of the road accident phenomena: the interpretations are related to the consistency of the used data. The survey over a wide area can be carried out by three different levels of analysis. The first is a macroscopic level by aggregated data and with a minimal detail. A second level deepens the investigations that can cover those sub-areas for which has been possible to detect presence of some accident phenomena. This more detailed investigation (meso-level) needs for focus gather further careful data, analysis and formulation of specific actions only for those safety situations that the second level has highlighted. For these situations, at end, it can upgrade to a more detailed level and therefore more expensive. This level (micro level) can require a study of every single accident report in the area. The procedure is general and can be applied to the analysis of traffic safety on rural roads or on urban roads. In the work an example of safety analysis sequence for a town of small / medium size will be considered, with the analysis and processing of technical steps that were valued necessary.
Head-on collisions cause more serious consequences of road accidents. These collisions are often ... more Head-on collisions cause more serious consequences of road accidents. These collisions are often due to an error of passing maneuver, on two-lane highways. The Passing Sight Distance (PSD) has always been a subject of studies and research that underline two series of factors that influence the PSD mainly: the first is the size and performance of vehicles, the second is the driver responses to environmental stimuli. This paper presents a study on the differences in some current procedures and guidelines used to estimate minimum PSD requirements for highway design. The research starts from a field study of passing maneuvers on two-lane highways and from a collection of characteristic data of passenger cars. A data obtained by video recordings was used to study some factors influencing the distance value as the actual speed, acceleration (pickup) of vehicles. From the two classical rule models (flying passing, Italian rules, accelerative passing, U.S.) and some modified to these it has simulated the PSD values with data brought by physical characteristics and performance of the passenger cars sold in Italy. The data were corrected with some behavioral characteristics hypothesized for the drivers. It has been supposed three kinds of drivers: a prudent, a normal and an aggressive driver. These drivers with different behavioral kinds influence the simulation data. At the end is showed an analysis of different PSD models and a first approximate model that could link the PSD to the passing vehicle speed.
The annual ACI-ISTAT statistics report, constantly, among the major causes of accidents the drive... more The annual ACI-ISTAT statistics report, constantly, among the major causes of accidents the driver behavior and speed (also considered in the work as an expression of the behavior of the driver). The two aspects of the problem can be considered as cultural. The first is influenced by a culture current (unofficial) according to which a casual and not respectful of the rules way of driving is a sign of a strong and independent character; the second is, probably, is the result of a specialized culture which tends to confirm the easy, but not always correct, equation in which the speed leads to the accident inevitably. It is necessary, then, to learn more about these causes of accidents to be able to formulate objectively, quantitative evaluation on road safety and to implement, as a result, rigorous measures leading to a substantial reduction in the number of accidents without penalizing, and still unnecessarily, the act of transport. These assessments can and should affect also, and a...
Natural Hazards
Over the past few decades, intense urban expansion has occurred over the Campi Flegrei territoria... more Over the past few decades, intense urban expansion has occurred over the Campi Flegrei territorial system without considering the volcanic risk. In this active volcanic area, where a short period evacuation could be necessary, the emergency management cannot be based solely on hazard-related information. The territorial and social features must also be considered. In this framework, the main purpose of this research is to point out the seriousness of the present setting of the Campi Flegrei territorial system in case an evacuation is necessary. Following the concept of regional evacuation, the zone to be involved in emergency planning was identified as the whole of the area threatened by the volcanic events of the past 10 ka. Inside this area the spatial relation between the resident distribution and the outflows of roads, railway stations and harbours, to facilitate evacuation, was investigated. A spatial relational GIS-based procedure was used to draw the territorial system vulner...
The basis of a planning process is the evaluation of capacity, both in case of exnovo infrastruct... more The basis of a planning process is the evaluation of capacity, both in case of exnovo infrastructures and extensions of existing ones. Therefore, the evaluation of capacity is particularly important for an airport so that a correct infrastructure dimension can be obtained.
Applications of Advanced Technologies in Transportation Engineering (2004), 2004
The highways speed diagrams is a essential tool for correct geometric roads design, for geometric... more The highways speed diagrams is a essential tool for correct geometric roads design, for geometric layout characteristics control (visibility distances, relationships between following elements, climbing lanes for the trucks) in existing roads, and, together with the vehicles masses information, for the safety barriers adequate sizing. These operations could be well execute if, at the same time, is increased the speed characteristics knowledge on the accident risk zones. In this paper is described a method in order to tracing that; it leaves from solely mechanics and performance hypothesis, own to the vehicle, and uses an experimental relationship derived from the instantaneous vehicles speeds distributions, recorded at significant time intervals, and different geometric layouts. The investigations has been realized on different two lane highways and they have consented to characterize a linear dependence relationship for geometric design elements speed and the desired speed, for thi...
National statistics show, constantly, that the greatest number of road accidents occurs in urban ... more National statistics show, constantly, that the greatest number of road accidents occurs in urban areas. These official data have been and are still the subject of studies that have different results of rather general. It 'also possible that they are aggregated according to various logical and several probable causes. We have to consider that road safety is the result of a delicate balance that results from three factors: • the driver (information perception, driving decisions, trajectories and adopted speed); • vehicle (interaction with the road, performance); • Environment (geometric characteristics, lighting conditions and weather). Due to the complexity of the safety phenomenon seems appropriate to use for it understanding not only the analysis of aggregated statistical data but also the study of individual accident records, as reported by police agents. This study is expensive, time-consuming, but provides a range of information not otherwise available. These, with the road ...
Procedia - Social and Behavioral Sciences, 2014
The objective of this paper is study the driver behaviors in the vehicle platoons starting from a... more The objective of this paper is study the driver behaviors in the vehicle platoons starting from a traffic light. This study i s necessary to model the changes in the shape of the vehicle platoons at different sections along the road. It is need to understand these changes in order to define an adequate programming of the traffic light phases. The study started from a survey of traffic flows on a road section of about 650 m.: all vehicles have been followed from the start section and for each of them were recorded the transit times on next sections at known distance. The data have been analyzed with two different methods: Cyclic Flow Profiles and the Weibull distribution. The calibrated CFP, with correct parameter values, well represent the trend and the dispersion of vehicle platoons at the observed road section. The Weibull distribution, basic used to describe life-time reliability characteristics in model failure testing, can be a powerful tool also for the prediction of vehicle platoons on the road sections. Fact, starting from the flow study in a number of sections, it is possible to know the trend of distribution parameters as function of the start distance. The variation of two parameters along the road from the first section (first signal light) appears to be linear for the first parameter (position), almost linear for the second (form).
The traffic light coordination is often considered as a measure to improve traffic speed by reduc... more The traffic light coordination is often considered as a measure to improve traffic speed by reducing car emissions per meter. Although the dynamic approach has been widely developed in theory and application, the static approach can be still useful in many design problems. Often design is made by static approaches and is also verified with dynamic models. The static approach studied in this paper starts from flow profiles of vehicle platoons departing from a traffic light. Several past studies have been concerned with the definition of flow profiles and in this paper it considers modeling with the collected data by using the approach of cyclic flow profiles (TRANSYT TRRL) which gives the arrival distribution of flow platoons as a function of the distance from the first intersection through a recurrent computation. It can know the car number that is in late for the green phase at the second light and then decide to increase the second green time according to the access waiting time o...
This paper analyzes the problem of the inclusion of road infrastructure in the present environmen... more This paper analyzes the problem of the inclusion of road infrastructure in the present environment; in fact many international and national studies and research have been carried out to address this aspect of road infrastructure construction. Although many approaches to this type of problem exist, now there are two main procedures to solve it: a) the surrounding environment seen from the road (i.e. from the perspective of the driver's eye), and b) the whole surrounding environment observed from off the road (the point of view external to the road). The experimental analysis presented here shows a predictive model to assess the beauty of a scenario in which the road is introduced from the road. The model has been developed thanks to experimental investigation using a sample of 200 non-expert judges asked to express an opinion on 32 different scenes in conventional photographs selected from low-volume roads within the Province of Salerno. The coefficients of the resulting model ha...
The increase in traffic flows on the roads causes an increase in road accidents. The study of the... more The increase in traffic flows on the roads causes an increase in road accidents. The study of the road safety deals on how to reduce the related phenomenon to non-pathological levels; to be able to operate correctly, much different information are needed. For some different levels of investigation of the phenomenon, only the incidental statistics may be necessary. To plan the interventions it needs information on the single incidents that occur in some areas. Each incident has some evolution characteristics that are repeated in a non-random manner, and these recurrences must be highlighted and studied to obtain effective countermeasures. The study methodologies of the road accidents maybe not only on their typology and imply the possibility of reconstruction, even if approximate, of the incident and its temporal phases of development. In some cases, it may also be necessary to evaluate the impact speed between vehicles. Some incident reconstruction techniques allow obtaining reliabl...
The Linear Scheduling Method (LSM) is the most effective scheduling tool to use in linear project... more The Linear Scheduling Method (LSM) is the most effective scheduling tool to use in linear projects. Computer programs have been developed for various scheduling techniques such as Bar Chart, PERT and CPM. There are not many commercially available toolkit for LSM and this lack of toolkit is one of the reasons for its limited usage. The product of this research is a toolkit comprised of models, procedures and tools that allow for implementation of the linear scheduling method. This toolkit is able to calculate the controlling activity path of such schedules, to level the resources of a project scheduled and to print reports of the status of the schedule. The paper describes the toolkit that was developed by the research, its documentation and example for an Italian case study that was scheduled using this prototype.
The traffic light coordination is often considered as a measure to improve traffic speed reducing... more The traffic light coordination is often considered as a measure to improve traffic speed reducing car emission per meter. Although the dynamic approach has been widely developed in theory and application, static approach can be still useful in many design problems. Often design is made by static approaches and is also verified with dynamic models. The static approach study, in this paper, starts from flow profiles of vehicle platoons departing from a traffic light. Several past studies have concerned on the definition of flow profiles and in this paper it considers the collecting data modeling using the approach of cyclic flow profiles (TRANSYT TRRL) who gives the arrival distribution of flow platoons as a function of the distance from the first intersection through a recurrent computing. So it can know the car number in late for the green phase at the second light and then decide to increase the second green time according to the access waiting time or, conversely, reduce the green...
Transportation Research Procedia
Transportation Research Procedia
A survey for road safety must draw on a wide range of data, for the technician or researcher it i... more A survey for road safety must draw on a wide range of data, for the technician or researcher it is important to be able to access the databases organized and up to date. These data concern sure the incidents, the study area demographics, the current infrastructure data, traffic flows, but other data relate to different study problems. Without well organized bases the collection and analysis of data becomes an expensive phase that can and should be carried out, depending on the available resources, to a different levels of detail. Various levels of detail require the acquisition of different kinds of data. Their treatment may provide different indexes and accidents ratio that can bring different interpretations of the road accident phenomena: the interpretations are related to the consistency of the used data. The survey over a wide area can be carried out by three different levels of analysis. The first is a macroscopic level by aggregated data and with a minimal detail. A second level deepens the investigations that can cover those sub-areas for which has been possible to detect presence of some accident phenomena. This more detailed investigation (meso-level) needs for focus gather further careful data, analysis and formulation of specific actions only for those safety situations that the second level has highlighted. For these situations, at end, it can upgrade to a more detailed level and therefore more expensive. This level (micro level) can require a study of every single accident report in the area. The procedure is general and can be applied to the analysis of traffic safety on rural roads or on urban roads. In the work an example of safety analysis sequence for a town of small / medium size will be considered, with the analysis and processing of technical steps that were valued necessary.
Head-on collisions cause more serious consequences of road accidents. These collisions are often ... more Head-on collisions cause more serious consequences of road accidents. These collisions are often due to an error of passing maneuver, on two-lane highways. The Passing Sight Distance (PSD) has always been a subject of studies and research that underline two series of factors that influence the PSD mainly: the first is the size and performance of vehicles, the second is the driver responses to environmental stimuli. This paper presents a study on the differences in some current procedures and guidelines used to estimate minimum PSD requirements for highway design. The research starts from a field study of passing maneuvers on two-lane highways and from a collection of characteristic data of passenger cars. A data obtained by video recordings was used to study some factors influencing the distance value as the actual speed, acceleration (pickup) of vehicles. From the two classical rule models (flying passing, Italian rules, accelerative passing, U.S.) and some modified to these it has simulated the PSD values with data brought by physical characteristics and performance of the passenger cars sold in Italy. The data were corrected with some behavioral characteristics hypothesized for the drivers. It has been supposed three kinds of drivers: a prudent, a normal and an aggressive driver. These drivers with different behavioral kinds influence the simulation data. At the end is showed an analysis of different PSD models and a first approximate model that could link the PSD to the passing vehicle speed.
The annual ACI-ISTAT statistics report, constantly, among the major causes of accidents the drive... more The annual ACI-ISTAT statistics report, constantly, among the major causes of accidents the driver behavior and speed (also considered in the work as an expression of the behavior of the driver). The two aspects of the problem can be considered as cultural. The first is influenced by a culture current (unofficial) according to which a casual and not respectful of the rules way of driving is a sign of a strong and independent character; the second is, probably, is the result of a specialized culture which tends to confirm the easy, but not always correct, equation in which the speed leads to the accident inevitably. It is necessary, then, to learn more about these causes of accidents to be able to formulate objectively, quantitative evaluation on road safety and to implement, as a result, rigorous measures leading to a substantial reduction in the number of accidents without penalizing, and still unnecessarily, the act of transport. These assessments can and should affect also, and a...
Natural Hazards
Over the past few decades, intense urban expansion has occurred over the Campi Flegrei territoria... more Over the past few decades, intense urban expansion has occurred over the Campi Flegrei territorial system without considering the volcanic risk. In this active volcanic area, where a short period evacuation could be necessary, the emergency management cannot be based solely on hazard-related information. The territorial and social features must also be considered. In this framework, the main purpose of this research is to point out the seriousness of the present setting of the Campi Flegrei territorial system in case an evacuation is necessary. Following the concept of regional evacuation, the zone to be involved in emergency planning was identified as the whole of the area threatened by the volcanic events of the past 10 ka. Inside this area the spatial relation between the resident distribution and the outflows of roads, railway stations and harbours, to facilitate evacuation, was investigated. A spatial relational GIS-based procedure was used to draw the territorial system vulner...
The basis of a planning process is the evaluation of capacity, both in case of exnovo infrastruct... more The basis of a planning process is the evaluation of capacity, both in case of exnovo infrastructures and extensions of existing ones. Therefore, the evaluation of capacity is particularly important for an airport so that a correct infrastructure dimension can be obtained.
Applications of Advanced Technologies in Transportation Engineering (2004), 2004
The highways speed diagrams is a essential tool for correct geometric roads design, for geometric... more The highways speed diagrams is a essential tool for correct geometric roads design, for geometric layout characteristics control (visibility distances, relationships between following elements, climbing lanes for the trucks) in existing roads, and, together with the vehicles masses information, for the safety barriers adequate sizing. These operations could be well execute if, at the same time, is increased the speed characteristics knowledge on the accident risk zones. In this paper is described a method in order to tracing that; it leaves from solely mechanics and performance hypothesis, own to the vehicle, and uses an experimental relationship derived from the instantaneous vehicles speeds distributions, recorded at significant time intervals, and different geometric layouts. The investigations has been realized on different two lane highways and they have consented to characterize a linear dependence relationship for geometric design elements speed and the desired speed, for thi...
National statistics show, constantly, that the greatest number of road accidents occurs in urban ... more National statistics show, constantly, that the greatest number of road accidents occurs in urban areas. These official data have been and are still the subject of studies that have different results of rather general. It 'also possible that they are aggregated according to various logical and several probable causes. We have to consider that road safety is the result of a delicate balance that results from three factors: • the driver (information perception, driving decisions, trajectories and adopted speed); • vehicle (interaction with the road, performance); • Environment (geometric characteristics, lighting conditions and weather). Due to the complexity of the safety phenomenon seems appropriate to use for it understanding not only the analysis of aggregated statistical data but also the study of individual accident records, as reported by police agents. This study is expensive, time-consuming, but provides a range of information not otherwise available. These, with the road ...
Procedia - Social and Behavioral Sciences, 2014
The objective of this paper is study the driver behaviors in the vehicle platoons starting from a... more The objective of this paper is study the driver behaviors in the vehicle platoons starting from a traffic light. This study i s necessary to model the changes in the shape of the vehicle platoons at different sections along the road. It is need to understand these changes in order to define an adequate programming of the traffic light phases. The study started from a survey of traffic flows on a road section of about 650 m.: all vehicles have been followed from the start section and for each of them were recorded the transit times on next sections at known distance. The data have been analyzed with two different methods: Cyclic Flow Profiles and the Weibull distribution. The calibrated CFP, with correct parameter values, well represent the trend and the dispersion of vehicle platoons at the observed road section. The Weibull distribution, basic used to describe life-time reliability characteristics in model failure testing, can be a powerful tool also for the prediction of vehicle platoons on the road sections. Fact, starting from the flow study in a number of sections, it is possible to know the trend of distribution parameters as function of the start distance. The variation of two parameters along the road from the first section (first signal light) appears to be linear for the first parameter (position), almost linear for the second (form).