1,720,967 research outputs found
Procedure for the Identification of Existing Roads Alignment from Georeferenced Points Database
Full text linkThe aim of this research is to look for an automated, economical and fast method able to identify the elements of an existing road layout, whose original geometric design could date back to distant ages and could have undergone major modifications over the years. The analysis has been directed towards the Italian two-lane rural roads; the national public company ANAS made available its graph, obtained from high-performance surveys, that represents about 90% of these roads’ network. The graph is made up of a collection of georeferenced points but does not recognize or describe the geometric elements making up the roadway. Consequently, it has been necessary to design and develop an original procedure, subsequently implemented in a programming platform,
able to identify the characteristics of the several parts, which constitute the reference axes of the existing roads. This research focuses on the horizontal geometry assessing the coherence, consistency and homogeneity of the roads’ layout, through the ex post application of the regulatory model for the design verification. If road sections are identified in which some conditions are not significantly met, further investigation should be conducted in order to ensure road safety and to plan any road upgrading activities
Analisi di Floating Car Data (FCD) per lo studio delle velocità praticate dagli utenti negli elementi del tracciato stradale
Full text linkUno degli obiettivi principali da raggiungere per aumentare il livello di sicurezza stradale è quello di favorire un comportamento più corretto dei conducenti in termini di controllo del veicolo e di velocità selezionata. Una migliore comprensione della relazione tra le effettive velocità del veicolo e le caratteristiche geometriche dell'infrastruttura potrebbe svolgere un ruolo chiave nella selezione delle possibili azioni di sicurezza attiva.Il progetto prevede di confrontare gli FCD registrati su alcune strade selezionate con le velocità teoriche di progetto di queste infrastrutture e identificare se (e in tal caso, perché) esistono sezioni stradali che presentano un eccesso significativo tra velocità di guida e velocità di progetto
Results of Micro-Simulation Model for Exploring Drivers' Behavior on Acceleration Lanes
Full text linkThis study examines drivers' behavior on acceleration lanes, close to the convergence between the main and the secondary traffic streams, by means of traffic micro-simulations. Experimental data collected videotaping two acceleration lanes in Italy have been used to initially calibrate a simulation model and to validate it subsequently. The analyses had focused on both vehicles coming from the on-ramp, in terms of entrance points dispersion into the main traffic stream along the acceleration lanes, merging speeds, and acceleration rates reached, and on vehicles driving on the freeway right lane, in terms of vehicles categories, traffic volumes, and speeds. The maneuvers have been implemented in the TransModeler traffic simulation package and several scenarios have been considered, changing the traffic composition and the speeds at which drivers enter the acceleration lane from time to time. This led to obtain a large number of case studies, where the mutual influence between the two flows combined with the vehicle performances and the psychophysical characteristics of drivers, have led to an initial evaluation of the main variables in respect of which the required length for the specialized lanes depends. Road design guidelines' standards have been later compared to what was observed in reality and it can be claimed that the microscopic traffic model in some cases confirms the standards of road design guidelines while, in other cases, contradicts them
Optimizing Road Safety Inspections on Rural Roads
Full text linkRoad safety depends on a complex balance between all the factors that compose the road system: user, vehicle, environment, and infrastructure. Directive 2008/96/EC introduces procedures to improve the European Transport Network (TEN-T) safety, recognizing an important role for safety inspections, but focusing them on freeways and highways. This paper proposed methods and criteria useful to optimize current inspection procedures and adapt them also to secondary and local rural roads. It is often complex to determine the severity and weight of the different risk factors in this context, since deficiencies and faults can be found both in the road infrastructure and in the other components of the system. The proposed survey method was applied to a stretch of the SS7 Appia state road (Lazio, Italy). Producing video capture and using GPS sensors to geolocalize the data proved to be very useful for the compilation of the survey forms. The results showed a good consistency between the safety assessments obtained from the scoring of the inspection forms and the historical accident rate. Therefore, the proposed methodology can be a valuable aid in understanding safety concerns and in defining the improvement actions
Predictive Model to Assess Pollution from Road Runoff Waters as a Tool to Increase Sustainable Mobility
No full textThe United Nations’ 2030 Agenda for Sustainable Development emphasizes the crucial role of water management in human activities, yet the transportation sector has often overlooked water as a valuable resource. This paper delves into the potential of analysing road runoff waters, particularly in understanding pollutant generation and adopting mitigation measures. The methodology, developed in coherence with FHWA approaches, allows for the calculation of pollutant concentrations in road runoff waters following rainfall events. Results from a multi-case scenario highlight significant differences in pollutant generation between urban, extra-urban, and rural roads. Sensitivity analyses reveal the impact of rainfall intensity, drainage length, and traffic volume on pollutant concentrations. The study underscores the need for multidisciplinary approaches in infrastructure design and maintenance, considering ecological factors and regulatory mandates
Technical proposal for monitoring thermal and mechanical stresses of a runway pavement
Full text linkAirport pavements should ensure regular and safe movements during their service life; the management body has to monitor the functional and structural characteristics, and schedule maintenance work, balancing the often conflicting goals of safety, economic and technical issues. This paper presents a remote monitoring system to evaluate the structural performance of a runway composed of concrete thresholds and a flexible central runway. Thermometers, strain gauges, and pressure cells will be embedded at different depths to continuously monitor the pavement’s response to traffic and environmental loads. An innovative system allows data acquisition and processing with specific calculation models, in order to inform the infrastructure manager, in real time, about the actual conditions of the pavement. In this way, the authors aim to develop a system that provides useful information for the correct implementation of an airport pavement management system (APMS) based on real-life data. Indeed, it permits comprehensive monitoring functions to be performed, based on the embedded sensing network
Pavement Distress Estimation via Signal on Graph Processing
Full text linkA comprehensive representation of the road pavement state of health is of great interest. In recent years, automated data collection and processing technology has been used for pavement inspection. In this paper, a new signal on graph (SoG) model of road pavement distresses is presented with the aim of improving automatic pavement distress detection systems. A novel nonlinear Bayesian estimator in recovering distress metrics is also derived. The performance of the methodology was evaluated on a large dataset of pavement distress values collected in field tests conducted in Kazakhstan. The application of the proposed methodology is effective in recovering acquisition errors, improving road failure detection. Moreover, the output of the Bayesian estimator can be used to identify sections where the measurement acquired by the 3D laser technology is unreliable. Therefore, the presented model could be used to schedule road section maintenance in a better way
Photovoltaic road pavements as a strategy for low-carbon urban infrastructures
Full text linkUrban Heat Islands (UHIs) are expanding in anthropized areas, causing serious climatic consequences such as rising temperatures and citizens' discomfort. Several studies have identified and confirmed how the use of cool road pavements can mitigate and reduce the negative effects of UHIs. This study performs a microclimate simulation of San Pietro in Vincula Square in Rome through ENVI-Met software by replacing the current asphalt pavement in the parking area with a cool one. The proposed layout consists of light concrete pavers in the parking lots, parking aisles made of photovoltaic (PV) panels, and a perimeter hedge. The innovative use of PVs is analysed from the thermal and economic viewpoints alike. In the first case, its thermal characteristics like those of asphalt provide results in terms of air temperature, mean radiant temperature, and predicted mean vote close to the current ones. Furthermore, the energy analysis shows the PV's effectiveness in terms of economic impact. Indeed, the electricity produced by the proposed PV system is enough to light the area, and its surplus can power public activities such as electric vehicle charging. The initial investment would pay for itself in the 25-year service life as confirmed by the positive net present value (NPV), and the cash flow reveals a break-even point in the 15th year
Evaluation of Microclimate Benefits Due to Cool Pavements and Green Infrastructures on Urban Heat Islands
Full text linkOngoing climate change is manifesting in the expansion of the urban heat island (UHI) effect. This paper evaluates the microclimate benefits of cool pavements and green infrastructures in a historical square in Rome, Italy. The ENVI-Met software enabled us to conduct a microclimatic analysis of the examined square in July 2021, through a comparison of the thermal performances of the current asphalt and sampietrini pavement (AS) with three alternatives. The proposed options are to change the existing layout to include: light concrete slabs and green furniture consisting of 5 m high trees (LC+G1), a perimeter hedge with 5 m high trees (LC+G2), and a perimeter hedge with 15 m high trees (LC+G3). The effects of the road pavements as passive countermeasures to the UHI effect are investigated in terms of air temperature (AT), mean radiant temperature (MRT), and predicted mean vote (PMV). The results show that the existing asphalt pavement is the worst option, while the cool pavement integrated with vegetation is greatly beneficial to human thermal comfort. Compared to the current layout, LC+G3 is the best scenario, because it implies an AT reduction higher than 3 °C, a MRT reduction equal to 50%, and a maximum PMV value equal to 2.2
Reliability of Historical Car Data for Operating Speed Analysis along Road Networks
Full text linkIn recent years, innovative progress in information and communication technology (ICT) has introduced new sources for traffic data collection and analysis. On-board sensors like GPS-GPRS boxes, generally installed for insurance purposes, communicate information from circulating vehicles to data centers. Geographic location, date and time, vehicles’ speed and direction, are systematically transmitted and stored as Historical Car Data (HCD) from probe vehicles in the traffic stream. These databases provide a good opportunity to analyze the vehicles’ motion both in the temporal and spatial domains. The aim of this study is to pay attention to the reliability of this kind of data gathering. Since instrumented vehicles account for a small percentage of the entire vehicle fleet, it is important to understand if they can be considered as a sample representative of the whole population. The paper presents a comparison of speed data obtained from HCD with the ones recorded by inductive-loop detectors and microwave radar sensors; the performed analysis required the definition of specific methodologies and procedures. The obtained results show a high correspondence between the two sets of data. Therefore, HCD can be proposed for the detailed monitoring of, and studies on, the operating conditions of mobility along road networks
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