scholarly journals The evaluation of the surrogate safety measures along a pedestrian confined ramp of an old bridge

2020 ◽  
pp. 1-13
Author(s):  
Chiara Gruden
Keyword(s):  
Road Traffic ◽  
Travel Speed ◽  
Point Of View ◽  
Urban Context ◽  
Safety Level ◽  
Safety Measures ◽  
Pedestrian Bridges ◽  
Surrogate Measures ◽  
Surrogate Safety Measures ◽  
Behavioural Aspects

Pedestrians walk daily to meet their basic needs. Therefore, over the years it has been attempted to make urban context more livable, respecting the needs of weak road users. Pedestrian mobility is also growing strongly from the point of view of tourism, especially in the areas where government measures are taken to reduce vehicular flow in order to let the architectural and landscape assets more usable. Often tourist itineraries are made of narrow areas crossed by numerous pedestrians, leading to possible critical circumstances. The criticality is connected to a likely reduction of safety and use (comfort and possible delays). Confined spaces such as small streets or pedestrian bridges well exemplify the described situation. Particularly, pedestrian bridges are often composed of ramps with variable slopes and consist of different floors, making walking difficult and therefore reducing travel speed and limiting the mobility of users such as handicapped or elderly people. Starting from the geometrical evaluation of the old bridge of Mostar (BIH), this article provides some ideas for evaluating the safety of pedestrians during the journey on the bridge, under different flow conditions. The analyses were carried out starting from an estimate of pedestrian flows from video monitoring. Safety was then assessed thanks to the calculation of surrogate measures, based on the trajectories of individuals, obtained through tracking tools. Camera monitoring and inspections to survey infrastructure’s geometric features ease the procedure of data entering into image processing software. The evaluation of individual pedestrian trajectories and/or their interactions allows to estimate the movement variations through the study of parameters such as speed variation, pedestrian density and surrogate safety factors. Surrogate safety measures, indeed, are indicators calculated for a chosen pair of users interacting in the detected scene. Among these factors there are: relative speed (Delta-V), Time-To-Collision (TTC), Time Advantage (TAdv) and T2. All the above-mentioned kinds of measures are interesting to study generally the behavioural aspects of road traffic and, specifically, safety level and factors influencing it. The purpose of this work is to estimate the effects of induced pedestrian mobility on Mostar’s Ottoman bridge in terms of safety, with the aim of preventing negative scenarios that could lead to a bad infrastructural level of service. Keywords: road safety; pedestrian trajectories; surrogate safety measures.

scholarly journals Developing a New Surrogate Safety Indicator Based on Motion Equations

2014 ◽  
Vol 26 (5) ◽  
pp. 371-381 ◽  
Author(s):  
Hamid Behbahani ◽  
Navid Nadimi ◽  
Hooman Alenoori ◽  
Mina Sayadi
Keyword(s):  
Collision Avoidance ◽  
Safety Measure ◽  
Safety Measures ◽  
Motion Equations ◽  
Time To Collision ◽  
Safety Indicator ◽  
Probability Of Collision ◽  
Collision Avoidance System ◽  
Surrogate Measures ◽  
Surrogate Safety Measures

Collision avoidance system (CAS), with the help of surrogate safety measures is a beneficial tool for reducing driver errors and preventing rear-end collisions. One of the most well-known surrogate safety measures to detect rear-end conflicts is Time-to-collision (TTC). TTC refers to the time remaining before the rear-end accident if the course and the speed of vehicles are maintained constant. Different surrogate measures have been derived from TTC; however, the most important are Time Exposed Time-to-collision (TET) and Time Integrated Time-to-collision (TIT). In this paper a new surrogate safety measure based on TTC notion has been developed. This new indicator merges TET and TIT into one measure and gives a score between 0 and 100%, as the probability of collision. Applying this indicator in CAS as a safety measure will be more useful than TET&TIT, to reduce driver errors and rear-end collisions.

scholarly journals About the equivalent level of flight safety

2020 ◽  
Vol 23 (5) ◽  
pp. 8-18
Author(s):  
B. I. Bachkalo ◽  
V. I. Zolotykh
Keyword(s):  
The State ◽  
Point Of View ◽  
Flight Safety ◽  
Minimal Set ◽  
Safety Level ◽  
Safety Measures ◽  
New Approach ◽  
Guidance Documents ◽  
Definition Of ◽  
The Impact

The article analyzes the meaning of the term "equivalent flight safety". The need for such an analysis is due to the fact that there is no definition of this term in the guidance documents on engineering and aerodrome flight support. This creates the ambiguous interpretation of the meaning embedded in this term and the possibility of non-compliance with the necessary flight safety measures at the aerodrome. As a result of the analysis, the expediency of the use of the term "equivalent level of flight safety" when determining the aerodrome operational suitability is substantiated. Management of the state of the aviation system from the point of view of information theory is considered. As a result, it was established that the ability to assess the impact of each element of the aviation system on its security against the effects of hazardous factors makes it possible to increase the efficiency of managing the state of this security. Dependence of the aerodrome flight safety level on the legality of the aerodrome operation is shown. The feasibility of achieving the equivalent level of flight safety using a new indicator, the equivalence coefficient, is substantiated. The formula that allows to calculate this indicator is derived. The numerical value of the equivalence coefficient depends on the values of the coefficients of compliance with the aerodromes operational suitability standards. The minimal set of evaluated elements is shown which determines the value of each coefficient of compliance with the aerodromes operational suitability standards. A mathematical model that reflects the dependence of the coefficient of compliance value with the operational suitability standards on the estimated indicators is constructed. The coefficients and indicators considered in the article in aggregate represent a new approach to assessing the level of aerodrome flight safety. This approach can be successfully applied in assessing the level of flight safety by any element of the aviation system.

Modeling Interstation Travel Speed of Hybrid Bus Rapid Transit within A Bayesian Framework

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Ji-hua Hu ◽  
Jia-xian Liang
Keyword(s):  
Road Traffic ◽  
Travel Speed ◽  
Bayesian Framework ◽  
Bus Rapid Transit ◽  
Rapid Transit ◽  
Important Indicator ◽  
Main Road ◽  
Traffic Lights ◽  
Speed Distribution ◽  
Hybrid Bus

Interstation travel speed is an important indicator of the running state of hybrid Bus Rapid Transit and passenger experience. Due to the influence of road traffic, traffic lights and other factors, the interstation travel speeds are often some kind of multi-peak and it is difficult to use a single distribution to model them. In this paper, a Gaussian mixture model charactizing the interstation travel speed of hybrid BRT under a Bayesian framework is established. The parameters of the model are inferred using the Reversible-Jump Markov Chain Monte Carlo approach (RJMCMC), including the number of model components and the weight, mean and variance of each component. Then the model is applied to Guangzhou BRT, a kind of hybrid BRT. From the results, it can be observed that the model can very effectively describe the heterogeneous speed data among different inter-stations, and provide richer information usually not available from the traditional models, and the model also produces an excellent fit to each multimodal speed distribution curve of the inter-stations. The causes of different speed distribution can be identified through investigating the Internet map of GBRT, they are big road traffic and long traffic lights respectively, which always contribute to a main road crossing. So, the BRT lane should be elevated through the main road to decrease the complexity of the running state.

Machine Learning Methods to Analyze Injury Severity of Drivers from Different Age and Gender Groups

2018 ◽  
Vol 2672 (38) ◽  
pp. 171-183 ◽  
Author(s):  
Somayeh Mafi ◽  
Yassir AbdelRazig ◽  
Ryan Doczy
Keyword(s):  
Machine Learning ◽  
Injury Severity ◽  
Road Traffic ◽  
Sensitive Data ◽  
Learning Methods ◽  
Safety Measures ◽  
Crash Data ◽  
Machine Learning Methods ◽  
And Gender ◽  
Gender Groups

Access to non-biased and accurate models capable of predicting driver injury severity of collision events is vital for determining what safety measures should be implemented at intersections. Inadequate models can underestimate the potential for collision events to result in driver fatalities or injuries, which can lead to improperly assessing the safety criteria of an intersection. This study investigates how injury severity differs between drivers of various ages and gender groups using cost-sensitive data-mining models. Previous research efforts have used machine learning methods for predicting injury severity; however, these studies did not consider the consequences (cost) of incorrect predictions. This paper addresses this shortfall by considering the monetary cost of incorrect injury severity predictions when developing C4.5, instance-based (IB), and random forest (RF) machine-learning models. One model of each method was developed for four distinct cohorts of drivers (i.e., younger males, younger females, older males, and older females). Each model considered a selection of driver, vehicular, road/traffic, environmental, and crash parameters for determining if they significantly influenced driver injury severity. A five-year period of two-vehicle crash data collected at signalized intersections in the metropolitan area of Miami, Florida was used in the models. Results indicated that cost-sensitive learning classifiers were superior to regular classifiers at accurately predicting injuries and fatalities of crashes. Among cost-sensitive models, RF outperformed C4.5 and IB models in predicting driver injury severity for four groups of drivers. The models displayed substantial differences in injury severity determinants across the age/gender cohorts.

scholarly journals Influence of Legislation on Road Traffic Safety

2012 ◽  
Vol 22 (1) ◽  
pp. 75-81
Author(s):  
Marijan Rajsman ◽  
Georg-Davor Lisicin
Keyword(s):  
Traffic Safety ◽  
Road Traffic ◽  
Prognostic Models ◽  
Legal Regulations ◽  
Improvement Strategy ◽  
Safety Level ◽  
The Road ◽  
Road Traffic Safety ◽  
The Republic ◽  
Basic Hypothesis

The objective of this paper is to analyse road traffic safety in the Republic of Croatia based on the selected indicators which were used by the legislator in bringing the Law on Road Traffic Safety which has been in force since 28 July 2004, and the achieved effects in reaching the desired safety level in the three-year period from 2005 to 2007. The aim of the research is to establish a prognostic trend of the values of the studied indicators in the time period following the enforcement of new legal regulations. Adequate safety indicator values for the respective period were analyzed using the methods of analysis and synthesis, mathematical statistics as well as trend assessment based on the found mathematical prognostic models. Based on the results of this research it was found that the basic hypothesis according to which the implementation of new legal guidelines had to result in positive change in the condition of road traffic safety, failed to be confirmed. A change in the road traffic safety improvement strategy has been proposed as well as a more significant participation and recognition of the profession and science in this field which is of great significance for the society. KEY WORDS: influence of legal regulations, road traffic safety, effects and tendencies

scholarly journals Determination of ASI and THIV parameters based on the results of experimental and numerical research in relation to EU standards

2021 ◽  
Vol 338 ◽  
pp. 01025
Author(s):  
Michał Stopel
Keyword(s):  
Experimental Tests ◽  
Severity Index ◽  
Point Of View ◽  
The Finite Element Method ◽  
Safety Level ◽  
The Road ◽  
Road Sign ◽  
Numerical Research ◽  
Python Programming

Determining the values of ASI (Acceleration Severity Index) and THIV (Theoretical Head Impact Velocity) parameters during tests allows you to assign an appropriate class for a given type of object to determine the safety level and to give the CE marking. The paper presents the methodology for determining these parameters based on the EN 1317-1 and EN 12767 standards. The paper also presents a tool created with the use of the Python programming language, which, based on the results of experimental tests or the results of numerical calculations, allows to determine the ASI and THIV values. The values of key parameters from the point of view of normative tests were calculated based on the results of experimental tests of the road sign supporting mast and numerical analysis carried out for the same case using the Finite Element Method and LS-Dyna software, following the EN 12767 standard.

The unpredictability of behaviour in traffic. Some reflections

2015 ◽  
Vol 288 ◽  
pp. 108-112
Author(s):  
Kazimierz J. Pawelec
Keyword(s):  
Law Enforcement ◽  
Traffic Accident ◽  
Road Traffic ◽  
Point Of View ◽  
Penal Code ◽  
Expert Witnesses ◽  
Rules Set ◽  
Formal Point ◽  
General Standard ◽  
Safety Rules

A traffic accident is an unpredictable event, although it may be committed as a result of non-compliance with safety rules, i.e. the general standard specified in Art. 177 & 1 of the Penal Code, or the detailed rules set out in the Law on Road Traffic. Its important cause can also be absolutely unpredictable, deviating from the model behaviour of participants of traffic. They can mislead on another, which from a formal point of view is chargeable, for example, not yielding priority, cutting off traffic, failure to comply with particular caution when approaching the designated crossing points or other dangerous places. Rating non-model, misleading behaviour, repeatedly escapes the attention of law enforcement or the courts. A large part in this is also shared by expert witnesses in traffic and automobile technology, who in their opinions carry out legal assessments, especially the opportunities and obligations. This is an issue strictly dogmatic, not belonging to their competence.

New Reactor Safety Measures for the European Sodium Fast Reactor - Part I: Conceptual Design

2021 ◽  
Author(s):  
Joel Guidez ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Enrico Girardi ◽  
Bernard Carluec
Keyword(s):  
Fast Reactor ◽  
Heat Removal ◽  
Thermal Inertia ◽  
Lessons Learned ◽  
Reactor Safety ◽  
Fukushima Accident ◽  
Safety Level ◽  
Safety Measures ◽  
Sodium Fast Reactor ◽  
High Thermal Inertia

Abstract Following up the previous CP-ESFR project, the ESFR-SMART project considers the safety objectives envisaged for Generation-IV reactors, taking into account the lessons learned from the Fukushima accident, in order to increase the safety level of the European Sodium Fast Reactor (ESFR). In accordance with these objectives, guidelines have been defined to drive the ESFR-SMART developments, mainly simplifying the design and using all the positive features of Sodium Fast Reactors (SFR), such as low coolant pressure, efficiency of natural convection, possibility of decay heat removal (DHR) by atmospheric air, high thermal inertia and long grace period before a human intervention is needed. In this paper, a set of new ambitious safety measures is introduced for further evaluation within the project. The proposed set aims at consistency with the main lines of safety evolutions since the Fukushima accident, but it does not yet constitute the final comprehensive safety analysis. The paper gives a first review of the new propositions to enhance the ESFR safety, leading to a simplified reactor, forgiving and including a lot of passivity. This first version is supported by the various project tasks in order to assess the relevance of the whole design in comparison to the final safety objectives.

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