A Study on Driving Performance Along Horizontal Curves of Rural Roads

Several studies have indicated that road crashes are more likely to occur on horizontal curves than on straight roadway segments for a good number of reasons, the most important of which is associated with the driver's behaviour along the curve depending on his perception of the road geometry. However, the evaluation of the effects of curve features on driving performance still remains a critical issue for road safety and design. The main objective of this study is to investigate driver's behaviour and his perception of road curves, which is directly related to road safety. Specifically, the effects of some curve features (radius, transition curve, visibility, cross section) on driving performance are investigated through a multi-factorial experiment based on driving simulation. The driving speeds and trajectories of a sample of 34 drivers were statistically processed over 72 different curves distributed along three test scenarios. The main and interaction effects of the independent variables are described and discussed in the results section of this paper providing a significant improvement of the actual knowledge on in this field of research. In general, the results confirm that driving simulation can disclose the relationships between road design features and driver behavioural aspects that are crucial issues in creating a safer road infrastructure

Ugo Spirito e la riforma penale italiana

Il tormentato interesse di Ugo Spirito per il diritto penale costituiva da sempre una costante, un punto di riferimento, - o, per meglio dire, di orientamento decisivo - per i suoi totalizzanti itinerari speculativi. La riflessione penalistica, per quell'eminente filosofo, era un fatto centrale, una scelta ineludibile. Come tale, essa continuava a costituire una sorta di fiume carsico che nel dipanarsi del suo pensiero, nel susseguirsi delle opere date alle stampe, periodicamente riaffiorava

Comparing eye-tracking system effectiveness in field and driving simulator studies

Background: Several studies have been developed by combining the benefits of eye-tracking systems with driving simulators to simultaneously investigate driving behavior and the potential source of distraction. However, little effort has been spent in terms of eye-tracking validation in the driving simulator environment. Objective: The overall aim of this study is to validate an eye-tracking system within the context of a driving simulation environment by considering a specific urban context application. Methods: Both a field survey and a driving simulation experiment have been developed for a case study located in Rome, Italy. The selected real road sections and events have been reproduced on the driving simulator system and an eye-tracking has been used to record the eye movements both on board of a real vehicle and on the simulator. The eye movements of 14 participants in the field survey and 18 participants in the driving simulation tests, as well as their driving performances, have been collected while approaching an urban intersection and in relation to two specific road events: i) the presence of a speed limit sign and ii) the presence of a crossing pedestrian. Results: Eye tracker parameters and driving performances were compared between the real driving tests and driving simulator experiments in order to validate the eye-tracking system. It has been validated for both the events in terms of duration and distance of the eye fixation. Conclusion: The results demonstrate that the eye-tracking system stands as an effective tool for studies and applications in a virtual reality environment

"Test-site operations for the health monitoring of railway ballast using Ground-Penetrating Radar"

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On-site inspections of pavement damages evolution using GPR

Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of approximately 160 km/day at 40 km/h speed, on the average. After processing and first-checking, GPR profiles were divided into homogeneous sections according to the combination of different parameters (e.g. route analyzed, long distance conditions of regularity/irregularity in layers arrangement). In such context, a high consistency between surface damages, mismatches from the GPR scans, and boundary environmental conditions was demonstrated. In addition, deep mismatches were detected even for early-stage or unrevealed faults. The second set of surveys was carried out in autumn in high humidity conditions, due to recent rainfalls. 160 km of relevant routes from the same road network were investigated. Results showed a high consistency with those collected during the first-stage of surveys. Minor changes were found in those sections with low traffic loads (e.g. farther away from the biggest town of Rieti), whereas major mismatches were detected in wetlands (e.g. close to rivers), work zones, and nearby those sections already deeply damaged in the past. This work benefited from networking activities carried out within the EU funded COST Action TU1208 “Civil Engineering Applications of Ground Penetrating Radar”

Evaluation of driving performance after a transition from automated to manual control: a driving simulator study

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GPR data collection and processing strategies for railway ballast evaluation

Railways are important assets requiring continuous and effective monitoring. Within this context, non-destructive testing (NDT) methods are gaining momentum including, amongst others, the ground-penetrating radar (GPR) technique. GPR has proven its viability at providing effective condition-based assessment of railway ballast and identifying several different sources of decay. In this paper, the main challenges related to the data collection and processing stages for railway ballast investigations are reported. In addition, a review of main survey protocols and data processing strategies, including state-of-the-art research in this area of endeavor is presented, in terms of the issues related to the configuration of the track-bed structure (i.e., the effects of rails and sleepers on the signal) and the main inspection targets (i.e., ballast fouling, water content and segregation of the aggregates)

Carbon Dioxide: A Raw Material for Cementitious Mortar

Buildings and infrastructures can absorb CO2 from the atmosphere because of the carbonation process that affects the calcium hydroxide of concrete elements. The aim of this research project is to initiate the absorption at casting by adding dry ice pellets to cement-based mortars. Test results demonstrate that the flexural and compressive strength of the mortars are not modified by this addition. Conversely, due to the presence of CO2, the standard deviation of strength reduces with respect to that measured in plain mortars. Thus, carbon dioxide can be considered a valuable resource that improves the mechanical behavior of construction materials

The Effect of Surface Brightness Dimming in the Selection of High-z Galaxies

Cosmological surface brightness dimming of the form $(1+z)^{-4}$ affects all sources. The strong dependence of surface brightness dimming on redshift z suggests the presence of a selection bias when searching for high-redshift galaxies, i.e. we tend to detect only those galaxies with a high surface brightness (SB). However, unresolved knots of emission are not affected by SB dimming, thus providing a way to test the clumpiness of high-z galaxies. Our strategy relies on the comparison of the total flux detected for the same source in surveys characterized by different depth. For all galaxies, deeper images permit the better investigation of low-SB features. Cosmological SB dimming makes these low-SB features hard to detect when going to higher and higher redshifts. We used the GOODS and HUDF Hubble Space Telescope legacy datasets to study the effect of SB dimming on low-SB features of high-redshift galaxies and compare it to the prediction for smooth sources. We selected a sample of Lyman-break galaxies at z~4 (i.e. B-band dropouts) detected in all of the datasets and found no significant trend when comparing the total magnitudes measured from images with different depth. Through Monte Carlo simulations we derived the expected trend for galaxies with different SB profiles. The comparison to the datahints at a compact distribution for most of the rest-frame ultraviolet light emitted from high-z galaxies.Comment: Accepted for publication in ApJ. 2 figures, 5 table

Prediction of rutting evolution in flexible pavement life cycle at the road network scale using an air-launched ground-penetrating radar system

In this work, the evolution of damages in pavement life cycle relative to rutting has been modeled in relevant pavement sections. Ground-penetrating radar (GPR) surveys were carried out at the rural road network scale using an air-launched pulsed radar system, 1GHz central frequency of investigation, linked to an instrumented van for collecting data at traffic speed. Surveys were performed in two time periods, six months apart from each other. By knowing the geometrical, traffic, climatic and construction information of each surveyed pavement section, and on the basis of comprehensive literature studies dealing with rutting versus time measurements in several flexible pavement sections during their life cycle, it has been possible to determine a reliable domain of existence by means of rutting versus time prediction curves, in which to locate the pavement section-specific prediction curve, case by case. Results have shown reliable relationships, wherein damage prediction is consistent with those suggested by literature