89 research outputs found
Compensation effect between deaths from Covid-19 and crashes: The Italian case
Abstract Emergencies such as the Covid-19 pandemic pose several decision-making issues, while clear evidence of successful strategies are still unavailable, different policies may be identified. However, in such emergencies, the preservation of public health, by firstly reducing human loss of life may be prioritized and then restrictive measures are implemented. The trade-off between damage due to the threat and the decrease in damage due to the lockdown is largely unexplored. Here we show that there is a degree of compensation between damage from epidemic deaths and from traffic deaths, especially in the case of immediate restrictive measures imposed by governments. Based on the Italian case, we found that damage from loss of human Capital and health care costs could have been fully compensated if the lockdown had been imposed ten days earlier. Considering only one Italian region (Puglia), where the epidemic was delayed and then restrictions were timely, damage due to loss of human Capital was largely compensated in the real scenario. However, damage due to loss of welfare could not have been fully compensated for, since Covid-19 deaths largely outnumber traffic deaths in the simulated epidemic period and loss of welfare damage is scarcely dependent on the age-at-death. From a broader perspective, societies seem to react to external threats as a whole organism, thus tending to restore the original equilibrium. Governmental decisions could accelerate this process. However, in the case of similar threats, some wounds cannot be compensated for, such as the incalculable damage due to loss of welfare
The deviation angle for one-lane roundabouts: A general mathematical formulation and application
Abstract Properly designed roundabouts may lead to safety improvements based on both reducing approaching speeds and controlling traffic. Measurements of deflection of vehicle trajectories are commonly used to estimate roundabout speed control. One of these measurements is the deviation angle, which is mentioned in both the Italian and Swiss road standards and, in specific conditions, can be more effective than other methods. This article presents a general mathematical formulation for linking several geometric parameters with the deviation angle in different rural and urban one-lane roundabout configurations, which is currently missing in the literature. For urban roundabouts, refuge islands for pedestrians and cyclists were considered. Based on the proposed formulation, a sensitivity analysis of the influential geometric parameters was conducted. Results suggest that an insufficient deflection of trajectories (deviation angle less than 45°) is always present for roundabouts with inscribed circle diameter less than 25 m; for urban roundabouts with refuge islands for pedestrians and cyclists having inscribed circle diameter less than 34 m and orthogonal legs; and for roundabouts with angles between opposite legs smaller than 140°. The main parameters which are responsible for a decrease in the deviation angle are: a decrease in the inscribed circle diameter; a decrease in the angle between opposite legs; and an increase in the width of the circulatory lane. Some optimized procedures for roundabout design, the generalized application of the deviation angle method and alternative speed control measures in cases of small deviation angles are discussed
Investigating the Deviation Angle Method for Ensuring Deflection at One-Lane Rural Roundabouts
Roundabouts developed as a road intersection design option has resulted in a series of nonuniform design guidance criteria in Europe, as well as in the United States and other Countries. In addition to different design specifications about the geometry of the elements constituting a roundabout (width and lanes of the circulatory roadway, entry and exit legs, splitter island), the methods for guaranteeing that vehicle paths deflect through the roundabout are also different. These methods ensure proper travel speeds between conflicting traffic flows. Currently, the main parameters used by standards to control the deflection are the deflection radius, the entry path radius, and the deviation angle. After a comparison between International deflection methods for roundabouts, this study checks the geometric requirements of the deviation angle for more than 7.000 hypothetical one-lane rural roundabouts. The Computer-Aided Design (CAD) drawing of the roundabouts takes into account the range of variability of their main geometric parameters, according to the Italian Standard. Subsequently, a number of the considered roundabouts checked with both the entry path radius and the German methods. Some results showing the greater effectiveness of the less popular deviation angle method are discussed. The main aims of this paper are:1) to promote the deviation angle method, which is only used in Switzerland and Italy;2) to improve standards, as regards the applicability and validity of the deflection angle method;3) to help practitioners to know in advance the outcome of the deflection checks at the beginning of the iterative design process, once the boundary conditions are known
Integrated American-European protocol for safety interventions on existing two-lane rural roads
Abstract Purpose The main purpose was to integrate two strategies for road safety analyses (qualitative: audits, inspections; and quantitative: accident predictions) and develop a possible protocol for the safety interventions on existing two-lane rural road segments. Those road sections do not typically belong to the TEN-network, to which the 2008/96/EC Directive is mainly oriented. Hence, they could lack of methods for designing safety-based interventions. The main research questions were:Which possible problems can arise from the application of this protocol to real cases?Which data are practically needed?Which possible solutions can be provided for the highlighted problems? Methods The integrated protocol, including: 1) the HSM predictive method, 2) the EU Regulations, 3) the local road design standards, 4) some research developments; is applied to real two-lane rural road segments requiring safety-based interventions. Its application is divided in the typical road safety analysis stages. Results A wide list of possible problems was highlighted and addressed: 1) lack of data, 2) difficult comparison with current road standards in order to identify safety problems, 3) lack of methods for evaluating the skidding risk along the layout, 4) setting speed limits, 5) need for optimizing the selection of countermeasures based on their aims and their timely application, in different recurrent situations, 6) availability and comparison of predictive methods. Conclusions Based on the problems and solutions discussed, main advantages (1) the systematic approach, 2) the quantitative assessment of benefits, 3) the possible transferability) and disadvantages (difficulties in overcoming the lack of data and calibrated accident prediction models) of the method were remarked
safety of edoxaban 30 mg in elderly patients with severe renal impairment
Patients with atrial fibrillation (AF) and advanced chronic kidney disease (CKD) are at high risk of adverse events and are complicated to manage. There is little evidence on the effects of non-vitamin K oral anticoagulants in patients with severe CKD. Preliminary data in patients taking edoxaban whose creatinine clearance fell below 30 mL/min showed a low risk of stroke and major bleeding. The aim of our study is to test the safety of edoxaban 30 mg/day in patients with severe renal impairment with an estimated glomerular filtration rate (eGFR) of 15–29 mL/min. We analyzed retrospective data from 46 patients who had documented AF with severe renal impairment (eGFR between 15 and 29 mL/min). The follow-up, characterized by clinical examination and blood analysis, was performed at 3, 6, and 12 months. The main endpoint was the incidence of major bleedings or clinically relevant non-major (CRNM) bleedings or thromboembolic events. At the time of the data collection, the average follow-up was 9.13 ± 3.0 months. There were no major bleedings, strokes, systemic embolisms, or cardiovascular deaths reported: one non-cardiac death and five minor hemorrhages occurred. No differences related to the severity of CKD were observed in the left ventricular ejection fraction at echocardiography and in the thrombotic and hemorrhagic risk profile. In this explorative study analyzing patients with severe CKD treated with edoxaban 30 mg once daily, no major bleeding or thrombotic events were observed. Some minor bleedings were observed. While additional studies are necessary to confirm the results of this exploratory study, edoxaban 30 mg once daily appears to be safe in patients with severe CKD
Low-cost smartphone-based speed surveying methods in proximity to traffic calming devices.
Abstract The study is aimed at investigating the effectiveness of two smartphone applications for surveying speeds of moving objects. These applications are used for urban speed measurements. Once the most reliable application was selected among the available ones, its outputs were calibrated by using the speed from the GPS system mounted on the test vehicle as a benchmark. Thereafter, an experimental test was conducted for monitoring the influence of a raised crossing on the vehicle speeds in the urban environment, by using the selected smartphone application
The variability of urban safety performance functions for different road elements: an Italian case study
Abstract
Background
Urban safety performance functions are used to predict crash frequencies, mostly based on Negative Binomial (NB) count models. They could be differentiated for considering homogeneous subsets of segments/intersections and different predictors.
Materials and methods
The main research questions concerned: a) finding the best possible subsets for segments and intersections for safety modelling, by discussing the related problems and inquiring into the variability of predictors within the subsets; b) comparing the modelling results with the existing literature to highlight common trends and/or main differences; c) assessing the importance of additional crash predictors, besides traditional variables. In the context of a National research project, traffic volumes, geometric, control and additional variables were collected for road segments and intersections in the City of Bari, Italy, with 1500 fatal+injury related crashes (2012–2016). Six NB models were developed for: one/two-way homogeneous segments, three/four-legged, signalized/unsignalized intersections.
Results
Crash predictors greatly vary within the different subsets considered. The effect of vertical signs on minor roads/driveways, critical sight distance, cycle crossings, pavement/markings maintenance was specifically discussed. Some common trends but also differences in both types and effect of crash predictors were found by comparing results with literature.
Conclusion
The disaggregation of urban crash prediction models by considering different subsets of segments and intersections helps in revealing the specific influence of some predictors. Local characteristics may influence the relationships between well-established crash predictors and crash frequencies. A significant part of the urban crash frequency variability remains unexplained, thus encouraging research on this topic
Self-Reported Route Familiarity and Road Safety Negative Outcomes: First Results from a Transnational Survey-Based Study
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Searching for relationships between self-reported familiarity and road safety based on surveys with geographic variability
The study is aimed at understanding if (a) declared driving behavioural changes due to familiarity can be observed through surveys; (b) self-reported route familiarity can be related to negative safety performances (crashes and fines); (c) the relationships are stable across different countries. Driving on habitual routes could imply different behaviours than on generic routes, and possibly different safety performances. The relationships between route familiarity and safety performances are often searched through experimental studies or accident data analyses. Surveys were spread to young Italian and Norwegian drivers, asking both general and specific questions on the habitual route travelled and the recently experienced crashes and fines. 316 answers, 235 Italian and 71 Norwegian, were analysed. Comparisons of self-reported driving scores between generic and habitual routes were performed. Logistic regressions having as response variables negative outcomes (crashes and fines) on frequent routes, different behaviour on habitual routes, and nationality were developed. Different relationships were highlighted, concerning differences in perceived ability on the habitual route, a possible excess of self-confidence, which however are differently related to crashes and fines. Different tendencies were found for the same variables in the two countries, sometimes opposite. Surveys are suggested as useful to reveal familiarity-behavioural changes/negative outcomes relationships. Considering international studies may reveal significant driving behavioural differences and patterns. The results have some potential applications for driver education, since some relationships between familiarity effects in young drivers and negative safety outcomes were noted
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