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Road accidents are becoming a great social problem. According to international accidents database, road traffic crashes kill more than one million people a year: every minute two people lose their lives and seven people are seriously injured in road accidents all over the world. Road traffic crashes have been ranked the 11th major cause of death and account for 2.1% of all deaths globally. Many strategies have been introduced to reduce road risk and mitigate severe consequences of unavoidable crashes but the first step to select which road safety measures could provide the best benefits is an in depth accident analysis to identify the factors and the causes of road crashes. Taking a certain road safety problem as a starting point, a list of possible measures should be selected and rated, but the investigation of the problem is as crucial as complex step. The paper presents a methodology for the identification of those accidents caused by the road. It is necessary and useful to evaluate road “pathology” and to determine critical roadway deficiencies that contribute to crashes and to eliminate or mitigate them, drafting an effective road program for accident prevention.

The population is aging all over the world and the proportion of seniors is increasing from 10 to 20 % of the total population. The number of serious injuries due to crashes increases from about 50 crashes per billion km for the age groups from 25 to 65 years old to more than 250 crashes per billion km for the older age groups. The impact of older drivers on road safety is due predominantly to age-related impairments. Considering the difficulties, both in gaining older drivers’ compliance with safety measures and in avoiding difficult driving situations, and considering the limited effectiveness of additional in-vehicle devices, this paper proposes to enhance the safety of the infrastructure for elderly people. Studies examining roadway characteristics have mainly focused on intersections. Here, the roadway geometry has been analyzed. Two stretches of a very hazardous road were simulated using an interactive driving simulator. Two age groups of young and older drivers were tested. The speeds of younger and older drivers were compared along the roadway. The understanding of the road was also assessed through a comparison of the two age groups. It was found that, if the geometry of the roadway is complex and tortuous, the speeds of older subjects are generally much lower than the speeds of younger subjects. The dispersion of speeds is always much greater for older rather than for younger drivers. From the outcomes of this study, the self-understanding road is expected to be self-understanding for both younger and older drivers, but at a different level. Younger drivers make more correct manoeuvres than older drivers. This study concludes that the older drivers experience more difficulties in understanding roadway geometry.

Skid and hydroplaning induced by water film on pavement are critical problems for road safety. Porous pavements are considered to potentially be effective solutions. A new low cost and user friendly piece of equipment for measurement of Darcy hydraulic permeability of pavement is presented in this study. The reliability and repeatability of measurements have been verified. The main points used to verify the strength of the equipment, recently patented in Italy, follow: (i) the measurement is developed before pavement construction in the laboratory and it is possible to optimize the mix design, (ii) Marshall samples were used for hydraulic measurements, unless destruction or perturbation was necessary, for subsequent mechanical testing, (iii) standard cores extracted from existing pavement can be inserted into the instrument to measure the current hydraulic permeability, (iv) the equipment measures permeability, assuming homogeneity and isotropy as a hypotheses, (v) the equipment is low in cost, both for materials and for technology, (vi) no electric or other power is needed, it works under hydraulic load, (vii) the equipment works both at constant and at variable hydraulic load. Finally, the experimental outcomes of a research project are discussed, in order to assess the correlation between the hydraulic permeability of pavement and bitumen content, which voids percentage and aggregate grading. Very cautious standards for mix design are imposed in order to have adequate permeability, and this is validated after pavement development. The final permeability obtained respecting those standards is always higher than the needed one. It induces relevant economic and environmental costs. After verifying in the laboratory the hydraulic permeability and the mechanical resistances of the 24 pavement samples, the effectiveness of an experimental procedure for the optimization of the mix in terms of hydraulic and mechanical standards has been assessed. Outcomes show that permeability always decreases if Young’s Modulus increases. Aggregate grading influences this relationship and the procedure of making of samples influences the mechanical and hydraulic final characteristics. Relevant economic and environmental benefits are a reasonable expectation.

Road safety is one of the most crucial problems all over the world. Traditional approach to the design of safe roads is based on kinematical and dynamic equations that impose geometrical requirements for each single element. The increase of traffic flows causes a severe problem of vehicle interferences when the levels of service of the road decrease. It has a relevant impact on safety. At the same time, the high value of vehicles density is determined by the overlapping of traffic flows generated by different motivations, from commuting, to tourism, from occasional mobility to exceptional events. These flows have completely different expectations from road and traffic. The conflict between the drivers’ expectation and real level of service has an effect on the human threshold for risk acceptance. This effect is obviously different among the different components of traffic flow and it frequently leads to unsafe behaviors. This consideration has been confirmed by many risk assessments of existing roads. Traditional approach cannot investigate similar questions affected by human factors. Emerging technologies make it possible to evaluate the interaction among driver, vehicle and road environment (traffic, geometry, pavement, external conditions) through an interdisciplinary approach. Interactive driving simulators are generally used by psychologists and car manufacturers. Since some years simulators have been also used to improve the effectiveness of road safety studies under an interdisciplinary perspective. This paper presents the applications of interactive driving simulators to improve the safety of main rural roads. Three cases are discussed: the evaluation of driver’s reaction time under different conditions of mental workload, the reliability of theoretical assumptions for passing maneuver, the validation of advanced indicators for safety audits. The outcomes are interesting and sometimes they contrast traditional assumptions based on kinematical and dynamic hypotheses.

L'invenzione riguarda un dispositivo per la misurazione di permeabilità di materiali porosi, adatto particolarmente alla misurazione di permeabilità di conglomerati bituminosi per pavimentazioni stradali

A fronte di un evidente ritardo del nostro paese nel riutilizzo di rifiuti da costruzione e demolizione, il presente lavoro contribuisce ad una ampia verifica delle potenziali applicazioni di tali materiali per la realizzazione degli strati portanti della sovrastruttura stradale. La rilevanza dei risultati sperimentali è evidente considerando i significativi vantaggi economici e i benefici ambientali eventualmente perseguibili in un uso diffuso di tale materiale. Più nello specifico l'articolo sintetizza gli esiti di un'ampia campagna sperimentale sviluppata presso il laboratorio di strade dell’Università di Roma Tre. Verranno descritti metodi e materiali utilizzati per investigare la produzione di fino per effetto delle azioni meccaniche di costipamento operate sia sul materiale tal quale, sia sul materiale “corretto” con alcune frazioni granulometriche di inerti naturali: gli effetti indotti dai fenomeni di autocementazione sulle caratteristiche meccaniche del C&D “tal quale" e corretto, al variare dell’umidità di confezionamento; l’incremento delle resistenze meccaniche indotto dalla stabilizzazione con cemento al variare dell'umidità di costipamento, per il materiale tal quale e corretto, per tempi diversi di stagionatura. I risultati ottenuti pongono in evidenza come le azioni meccaniche del costipamento siano responsabili di una rilevante produzione di fino. ciò non consente un adeguato riscontro tra il C&D approvvigionato all'impianto e quello posto in opera. Peraltro si è osservato come l'usuale tecnica di correzione adottata attraverso la singolare sostituzione di una singola classe granulometrica non realizza un reale beneficio in quanto questa determina una frizione che in alcuni casi incrementa la produzione di fino e finissimo, Rispetto al contenuto d'acqua si è riscontrato che per basse umidità prevalgono i fenomeni di plasticizzazione in quanto nel medio periodo un apprezzabile in-cremento di resistenze si realizza solo se si in-nescano fenomeni di ce-mentazione. Tali processi risultano più evidenti quando, per il campione corretto granulometricamente. si verifica un minore assorbimento di acqua e si realizza un efficiente scheletro litico. Nel caso invece dell'aggiunta di un'adeguata percentuale di legante cementizio, si possono ottenere risultati di particolare interesse e presumibilmente compatibili con le qualità meccaniche richieste per gli strati di base della sovrastruttura stradale sempre che: si provveda alla correzione con materiali naturali atti a garantire l'affi-dabilità dello scheletro litico e si adotti un'umidità di confezionamento tale da garantire l'efficienza dei fenomeni di presa. In Italy there is a delay in employing the waste from construction and demolition. This study carries out checks on potential applications of these materials to realize load bearing layer of road pavement. The experimental results show very clearly big advantages, especially if we consider the big economic and environmental advantages using these materials. Specifically the article synthesize the results of a wide campaign developed in the laboratory of Roma Tre university. Will be described materials and methods to investigate the production of fine materials due to the mechanical actions of the machines for the compaction both on the row material and the corrected (adjusted) material adding fractions of natural aggregate the effects due to the setting on the C&D features, varying the humidity of confection; the increase of the mechanical characteristic due to the cement stabilization varying the humidity during compaction, for the row material and the corrected one, for different time of maturation. The result shows how the mechanical actions during the compaction, are responsible for a big production of fine material. Because of this effect there is a difference between the C&D at the production site and the layed down C&D.Moreover has been observed how the traditional technique for the correction of the material adopted by the substitution of a single granulometric class doesn't realize a real advantage because it helps the production of fine and very fine material. In respect with the water content has been observed that with a low humidity prevail plastic phenomena because at medium term there is a increase of resistence only if hydratation starts.

Interactive driving simulation offers today very promising perspectives in the field of road safety design and management. At the same time it implies a “revolutionary” approach respect to the traditional road engineering models. In fact the consolidated theories, starting from kinematical and dynamical hypotheses, are based on assumption that are not experimentally validated under different conditions of traffic flow, weather, boundary conditions, etc.. Advanced technologies such as driving simulators make it possible investigate the role of human factors under a multidisciplinary perspective. It looks like turning from a theoretical approach to a new experimentally validated scientific investigation methodology. The first outcomes are absolutely promising and they refers to three main field of applications and study: the theoretical investigations, the road projects validation and the road safety audit and assessment. The paper discusses the cultural context and presents an overview on significant applications. Finally the perspectives of simulation for road safety are outlined.

We investigate the relation between the dielectric constant of soils and their volumetric water content to be used in non- invasive measures of water content, like Ground Penetrating Radar ( GPR). After modeling the porous medium as a Multi Indicator structure, we derive the effective permittivity of the soil as function of the water content by adopting the effective medium approximation. The derived formula is tested against controlled, laboratory experiments.

This book, based on Transport and Urban Development COST Action TU1208, presents the most advanced applications of ground penetrating radar (GPR) in a civil engineering context, with documentation of instrumentation, methods, and results. It explains clearly how GPR can be employed for the surveying of critical transport infrastructure, such as roads, pavements, bridges, and tunnels, and for the sensing and mapping of underground utilities and voids. Detailed attention is also devoted to use of GPR in the inspection of geological structures and of construction materials and structures, including reinforced concrete, steel reinforcing bars, and pre/post-tensioned stressing ducts. Advanced methods for solution of electromagnetic scattering problems and new data processing techniques are also presented. Readers will come to appreciate that GPR is a safe, advanced, nondestructive, and noninvasive imaging technique that can be effectively used for the inspection of composite structures and the performance of diagnostics relevant to the entire life cycle of civil engineering works.

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