1,721,146 research outputs found
Il progetto delle corsie di sorpasso nelle strade extraurbane a carreggiata unica
No full textLe corsie di sorpasso costituiscono corsie aggiunte ad una strada extraurbana a due corsie con carreggiata unica per incrementare le possibilità di sorpasso, e si differenziano dalle corsie di arrampicamento in quanto sono installate su terreno pianeggiante o ondulato. Il loro utilizzo è motivato dalla necessità di migliorare il livello di servizio, ovvero di aumentare lo sviluppo di tracciato in cui è consentito il sorpasso; allo stesso tempo le corsie di sorpasso possono consegnare benefici anche in termini di riduzione dell’incidentalità. Nel presente articolo, si propongono dei criteri di progetto per le corsie di sorpasso che tengono conto sia delle esperienze internazionali sia delle indicazioni del Codice della Strada. Al fine di fornire una misura quantitativa della convenienza delle corsie di sorpasso si è effettuata, per vari scenari di traffico e di geometria, un’analisi benefici/costi in cui i benefici sono espressi dalla riduzione dell’incidentalità e del tempo di viaggio. In presenza di scenari in cui la realizzazione delle corsie di sorpasso consente di passare da un livello di servizio insoddisfacente al livello C, individuati utilizzando la procedura HCM 2000, si sono riportati i risultati dell’analisi benefici/costi evidenziando poi le condizioni in cui le corsie di sorpasso sono più vantaggiose
Il calcolo del livello di servizio per le strade extraurbane secondo la procedura HCM 2000
No full textLa qualità nei laboratori di prova
No full textI laboratori di prova, in quanto organizzazioni che forniscono servizi, sono soggetti alle regole del mercato e devono pertanto essere strutturati e gestiti in modo tale da risultare competitivi soddisfacendo le esigenze e le aspettative del cliente e le esigenze interne dell’organizzazione. L'articolo definisce i requisii essenziali di un processo di gestione in qualità dei laboratori di prova
Collaborazione all’analisi critica comparativa delle norme italiane ed europee riguardanti le caratteristiche geometriche e funzionali della strada
No full text
Benefit/cost analysis for the selection of roadside safety alternatives
No full textIn EU, the new Standards EN 1317-1/2 define the performance classes of road restraint system and induce a growing interest for roadside safety. However, analytical procedures are not used for the selection of specific roadside safety features at specific locations or for the development of warrants, policies, and guidelines on a system-wide basis. In this paper, a new benefit/cost analysis procedure, based on an encroachment model, is presented. The new model, called SAFBAR, represents an improvement of the existing procedures and is very useful for selection of performance classses of safety barriers because it takes into account the effective performance level of road safety barriers, basing on the comparison between the impact conditions of the full scale crash tests performed according to the CEN standards and the real world impact conditions. The behavior of the safety barriers in relation to the impact conditions has been studied by performing non-linear dynamic finite element analysis of collisions of HGV against steel road safety barriers. As a result of the study, analytical relationships between barrier’s containment capacity and impact conditions have been obtained. The expressions allow to evaluate the number of vehicles correctly redirected from the safety barriers in relation to the type of road, to the geometrical characteristics of the road, to the traffic volume and composition and to the safety barriers containment level. The procedure allows to compare different types of measures, as relocation of utility poles and protection of utility poles with safety barriers, or measures of the same type carried out with different expenditure, as the installation of safety barriers with different performance levels
Benefit/cost analysis for the selection of roadside safety alternatives
No full textIn EU, the new Standards EN 1317-1/2 define the performance classes of road restraint system and induce a growing interest for roadside safety. However, analytical procedures are not used for the selection of specific roadside safety features at specific locations or for the development of warrants, policies, and guidelines on a system-wide basis. In this paper, a new benefit/cost analysis procedure, based on an encroachment model, is presented. The new model, called SAFBAR, represents an improvement of the existing procedures and is very useful for selection of performance classses of safety barriers because it takes into account the effective performance level of road safety barriers, basing on the comparison between the impact conditions of the full scale crash tests performed according to the CEN standards and the real world impact conditions. The behavior of the safety barriers in relation to the impact conditions has been studied by performing non-linear dynamic finite element analysis of collisions of HGV against steel road safety barriers. As a result of the study, analytical relationships between barrier’s containment capacity and impact conditions have been obtained. The expressions allow to evaluate the number of vehicles correctly redirected from the safety barriers in relation to the type of road, to the geometrical characteristics of the road, to the traffic volume and composition and to the safety barriers containment level. The procedure allows to compare different types of measures, as relocation of utility poles and protection of utility poles with safety barriers, or measures of the same type carried out with different expenditure, as the installation of safety barriers with different performance levels
Assessing Potential for Safety Improvement by Safety Reviews of Existing Roads
No full textTraditional road safety engineering work involves implementing relevant remedial measures at high accident locations. A new approach to road safety management is based on safety reviews of existing roads. Road safety review is aimed at identifying and solving risk factors, by trying to investigate how the road environment is perceived, and ultimately utilized by different road users. This approach overcomes the problems arising from poor quantity and quality of accident data. The paper describes the development of a Potential for Safety Improvement index that looks at factors impacting road safety and takes into account how safety measures can reduce accident frequency and severity. The methodology is based on safety reviews of existing roads. One consequence is that preliminary data are not needed. It allows Potential for Safety Improvement index calculation to be a flexible procedure, adoptable by every road agency. Moreover, safety reviews are spreading in many highways agencies around the world and the PSI index complements the review results in order to rank either the reviewed segments and the safety issues. Different PSI indexes are computed: the overall PSI, the PSI of the selected safety features and the PSI of the safety items, which are the characteristics that contribute to the global effect of the features. The specific indexes allow to point out safety concerns where improvements may be cost effective; the overall index provides a measure of potential for safety improvement of the road segments
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