1,721,147 research outputs found
L’adeguamento di una strada in relazione al sistema binario uomo-strada: applicazione e verifica locale dei modelli esistenti riferiti al calcolo della velocità operativa
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Adeguamento del patrimonio stradale esistente: riflessioni
No full textLa prevalente finalità della gestione del patrimonio infrastrutturale consiste nel mantenerlo adeguato alle funzioni assegnate a ciascuno degli elementi componenti, nell’ambito di una determinata vita utile. Gli interventi di adeguamento si rendono necessari a seguito di un’imprevista variazione delle funzioni richieste alla strada, che determina una riduzione della vita utile e/o l’inadeguatezza della stessa a soddisfare le nuove esigenze generate dalle variate condizioni di utilizzo.
Si propone che la gestione del patrimonio sia comprensiva delle attività di progettazione, di manutenzione e di adeguamento, finalizzate al mantenimento/miglioramento del servizio reso, più che da una singola strada, dalla rete della quale essa è componente, anche costituita da quegli elementi che vengono aggiunti, perché richiesti da esigenze di maggiore funzionalità derivanti, ad esempio, da variazioni del contesto territoriale, ove l’infrastruttura è inserita. In tal senso, il sistema infrastrutturale va gestito, adeguato e recuperato perché corrisponda alla funzione di contribuire al governo del territorio attraversato ed interessato, ed al suo sviluppo
Evaluation of the HCM Pedestrian LOS Methodology in Cagliari (Sardinia, Italy)
No full textThe United State Federal Highway Administration (FHWA) has published the Highway Capacity Manual (HCM) that provides procedures for analysing uninterrupted and interrupted pedestrian flows on walkways (Rouphail et al., 1998). Interrupted pedestrian flows refer to pathways intersected by traffic lights and other mechanisms to halt pedestrian flow for vehicular traffic. Since most of the walkways in National Parks in Victoria are exclusively pedestrian facilities, this report will only review the work relating to uninterrupted pedestrian flows.
The features of pedestrians are very important to examine: who is walking on sidewalks highly influence the performance of them and the characteristics of their traffic flow.
In the Highway Capacity Manual (HCM), published by the Transportation Research Board (TRB), there is a method to calculate and analysis level of service (LOS) in the USA. In order to estimate sidewalk comfort for pedestrians it is calculated the pedestrian level of service (LOS). It is used to design new sidewalks, to test the performance of a existent sidewalk, to decide its redesigning, to improve its width, to analyze its capability after a change, and so on. The HCM presents a measurement, that is adaptable, with indexes linked to places and times, to different sites.
However some international studies show that the HCM measurement of pedestrian LOS does not consider the complex pedestrian background under different situations: like, for example, environmental, and psychological factors which affect their travel expectations and needs. After surveying international literature and collecting and analyzing pedestrian data, our research group studied the HCM methodology and its application on Italy urban roads. The target of this article is to evaluate the HCM pedestrian LOS methodology in terms of its suitability for pedestrian planning in Italy, to compile a pedestrian features database, and to study pedestrian LOS analysis in Italy.
This study was concentrated in Cagliari, a city of Italy. Cagliari is the largest city in the Sardegna (a big island of Italy), but it is not a very big city. According to the census, 150,000 people lived in Cagliari. In the city there are different kind of people: citizens, students (who live there for studying, because there is the largest University of Sardegna), businessmen and workers (who only work in Cagliari but live apart), tourists, and so on.
This study is divided in two main parts. The first one is addressed to analyze the appropriateness of the HCM pedestrian LOS methodology for Cagliari. The second one aims to measure the factors that congestion the pedestrian flow on the sidewalks
Sulla gestione delle infrastrutture stradali: aspetti generali e metodologici dell'asset management
No full textNell'ambito del quaderno dal titolo "Sulla gestione delle infrastrutture stradali" del Comitato Nazionale C 4.1 "Gestione delle strade" dell'Associazione Internazionale Permanente dei Congressi della Strada presentato al XXV Convegno Nazionale Stradal
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A GEOSTATISTICAL APPROACH TO PREDICT 'OPERATING SPEED' ALONG HORIZONTAL CURVES ON TWO-LANE HIGHWAYS
No full textInjuries are one of the main causes of death according to W.H.O. For this reason the attention of road safety researchers especially regards the study of the relationship between driver and road environment.
Several research works show that operating speed is an excellent driver behavior parameter. This article describes a different approach to the classical definition of prediction models for operating speed on horizontal curves. In this paper, the fundamental theories, the applied operating procedures and the first results obtained with the application of Geostatistics are discussed. The mathematical models expressing operating speed in function of horizontal curves characteristics found in International scientific literature, have mainly been built on the basis of Classical Statistics. For this reason, it needs to be pointed out that the interpolative techniques found in Classical Statistics are based upon the use of canonical forms (linear or polynomial regressions) that completely ignore the correlation law between collected data. As such, the determined interpolation stems from the assumption that the data represent a random sample.
The models described in this article have instead been created with the geostatistical interpolation technique (i.e. Kriging). This technique allows to obtain the "best" estimates possible because it considers the true correlation law between the measured data.
The applied methods are then described along with the results obtained in the field of road safety by applying Geostatistics which, for several years, have been used, with positive results, in all scientific and engineering fields dealing with empirical data analysis and processing
Use of GIS technology in the checklist management
No full textThe use of the methodology “Road Safety Review” in the road safety analysis has been
spread for a long time. These methodologies are used to analyze in detail the different
components of the streets and to see which are the elements that affect adversely the
road safety. Checklists are drawn up in form of technical questionnaire and classified by
topic, each in turn divided by sub-topic. It’s clear that topics to be considered depend on
the element to be analyzed, whether it is an arc or a node. Indeed, checklists are divided
in two main macro areas, one for the arcs analysis and the other for the nodes analysis. In
this way, it is possible to study in detail each part of the road network and identify the most
critical areas. It is important to carry out on-visits in any arc and node, as well as to draw
up the checklists.
Once completed, a large number of data is available, but they are often difficult to be read.
In this study, we wanted to develop a management system checklist more fluid and
functional, whose main goal is to have an immediate overview of the network situation
under consideration.
The summary procedure can be resumed through the drawing up of the checklist with the
answers “yes”, “no”, “in part”, “n.a”, giving to each answer a score - according to its
influence on the road safety; calculating a weighted average for each subcategory and
finally, for each category.
The result of this analysis is then managed on a GIS platform and represented in graphics.
In this way, it is possible to have in real time an overview of the entire network under
consideration.
In this way, it will be possible to create a more efficient and manageable use of the
checklists
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