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• Importance of vehicular trajectory for sensing naturalistic instincts of the vehicles. • Instantaneous Perception Time is coined for quantifying vehicle attentiveness. • Safety thresholds for measuring the risk of rear-end collision. • Real time monitoring to check the performance of traffic stream. The present research work is initiated, probing for safety levels, evolving as an outcome of analysis of micro-level interactions due to naturalistic vehicular movements on Indian expressways. The research work reported here, devised a micro-level parameter, namely instant perception time (IPT) as a safety measure, which is a function of vehicular interactions. As a step towards deriving IPT, video-graphic surveys were conducted and traffic data was collected on two intercity Indian expressways. As a part of this work, first microscopic trajectory data was developed for capturing naturalistic driving behavior under heterogeneous traffic environment. Thereafter, hysteresis plots were developed between leader-follower pairs using relative speed and spacing between the vehicles. By means of the developed hysteresis plots, a novel approach for identification and quantifying chances of rear-end crashes using follower's Instantaneous perception time (IPT), is proposed in the present study. To study the IPT approach under different flow conditions, well-calibrated and validated simulation model is also developed using real trajectory data collected for the prevailing traffic conditions observed on the study sections. From the obtained IPTs using simulation model, three cluster ranges are delineated pertaining to different levels of risks of crashes. The cluster-analysis suggests that the least values of space-headway (m) and IPT (s) (space headway < 10.91 m, IPT < 5.61 s) at a given location shows most severe chances of rear-end collision. While, lower to moderate values indicate (with thresholds: space headway in the range 10.91–18.5 m; IPT 5.61–11.91 s), whereas higher values of IPT (more than 12 s) suggest the least chances of rear-end collision. The methodological approach, results and findings thus developed under naturalistic driving environment, presented here can be very useful in understanding the operational deficiencies of traffic streams, road geometry, coupled with safety assessment of traffic streams on uninterrupted roadway facilities. Furthermore, traffic control or geometry improvement related decisions can also be taken at different unsafe locations using IPT as a risk measure to enhance safety. [ABSTRACT FROM AUTHOR]

The pedestrian safety can be evaluated by proactive methods (conflict techniques). Proactive method is a cost-effective technique as compared to the historic crash data analysis. Pedestrian safety studies at mid-block crosswalks based on proactive methods are required due to the growing number of pedestrian crossing facilities in developing countries. Hence, the present study evaluated the pedestrian safety at unprotected mid-block crosswalks by considering the proactive safety measure as a pedestrian safety margin (PSM). PSM is the time difference between accepted vehicular time gap with reference to the pedestrian crossing path and pedestrian actual crossing time (based on the field conditions). To fulfill this objective eight unprotected mid-block crosswalks were selected which have different roadway characteristics. Video graphic survey has been conducted for data collection at these locations. PSM values were extracted corresponding to the pedestrian behavioural, vehicular and traffic characteristics at all the eight crosswalks. Further, stepwise regression and binary logit models (the probability of pedestrian-vehicle non-conflict) have been developed in order to find out the factors contributing to the PSM values as well as predicting the probability of avoiding conflict with an approaching vehicle at unprotected mid-block crosswalks. From the study, it is observed that pedestrian behavioural characteristics such as rolling behaviour and speed change conditions significantly reduce the PSM values, and it influences the probability of avoiding conflict with an approaching vehicle at unprotected mid-block crosswalks. These findings may be useful for evaluation of the existing unprotected mid-block crosswalk locations and for increasing the pedestrian safety at these crosswalks by considering suitable control measurements on pedestrian behaviour under mixed traffic conditions. [ABSTRACT FROM AUTHOR]

Objective The aim of this study was to evaluate the possibility of enhancing the visibility of motorcycles and pedestrians for motorists via safety messages concerning the vulnerability of these road users. Background In several cases of collision between cars and vulnerable road users (VRU), car drivers failed to detect the latter in time to avoid collision because of their low conspicuity. Method 2 groups of 17 motorists (23.6 years old) carried out a VRU detection task in 2 sessions in a car-driving simulator after either watching or not watching a film presenting safety messages about the vulnerability of these road users. Participants had to detect pedestrians and motorcyclists standing at the road side or who appeared on different parts of the road. Results The group of motorists who watched the film detected these VRUs at a greater distance and drove safely in zones which constitute a high risk of collision for pedestrians (key areas). Only the intensity of anger felt after the film can explain the improvement in VRU visibility distance. Moreover, this improvement was also associated with a modification in speed management in key areas. This last result provides evidence of the importance of top down processes in the detection of VRUs by motorists. Conclusion The film enhanced VRU visibility and led to safer driving behaviour for pedestrians. Application The practical implications of these results for safety campaigns and future directions of research on the emotional states of motorists and their perception during driving are considered. Short abstract We examine motorists’ ability to detect motorcycles and pedestrians (VRUs) in a simulated car-driving task after watching a film presenting safety messages about VRU vulnerability. Informed motorists detect VRU sooner and drive in a safer way for pedestrians. We also consider practical implications and futures lines of research related to safety campaigns. [ABSTRACT FROM AUTHOR]

Highlights: [•] CRFs are calculated to determine the reduction of crash index (crashes/mile) and injury severity levels of each group. [•] When the deceleration lane lengths are less than 400ft, the crash frequency decreases with the increment of the distance. [•] When the deceleration lanes are longer than 700ft, the crash frequency increases with the increment of the length. [•] For the one-lane exit, the minimum deceleration lengths are 500ft for the design speed of 55mph, and 700ft for 70mph. [ABSTRACT FROM AUTHOR]

Highlights: [•] Our study recommends not considering the DIC as the sole model selection criterion. [•] Comparison should be done between the models that have similar parameterization. [•] The study also recommends considering other alternatives in addition to the DIC. [ABSTRACT FROM AUTHOR]

Abstract: Fault tree analysis (FTA) is a logically structured process that can help identify potential causes of system failure before the failures actually occur. However, FTA often suffers from a lack of enough probabilistic basic events to check the consistency of the logic relationship among all events through linkage with gates. Sometimes, even logic relationship among all events is difficult to determine, and failures in system operation may have been experienced rarely or not at all. In order to address the limitations, this paper proposes a novel incident tree methodology that characterizes the information flow in a system instead of logical relationship, and the amount of information of a fuzzy incident instead of probability of an event. From probability statistics to fuzzy information quantities of basic incidents and accident, we propose an incident tree model and incident tree analysis (ITA) method for identification of uncertain, random, complex, possible and variable characteristic of accident occurrence in quantified risk assessment. In our research, a much detailed example for demonstrating how to create an incident tree model has been conducted by an in-depth analysis of traffic accident causation. The case study of vehicle-leaving-roadway accident with ITA illustrates that the proposed methodology may not only capture the essential information transformations of accident that occur in system operation, but also determine the various combinations of hardware faults, software failures and human errors that could result in the occurrence of specified undesired incident at the system level even accident. [ABSTRACT FROM AUTHOR]

Abstract: Because of rapid increase in the urban population and hence road traffic, the vehicle–pedestrian crashes are more frequent and have become a major concern in road traffic safety. Though the bumper of a vehicle plays an important role to protect the vehicle body damage in low speed impacts, many bumpers particularly in larger vehicles are too stiff for pedestrian protection and safety. To prevent lower extremity injuries in car–pedestrian collisions, it is important to determine the loadings that car front structures impart on the lower extremities and the mechanisms by which injuries are caused. In the present work, a dynamic legform impactor model is introduced and validated against EEVC/WG17 criteria. The collision mechanism between a GMT bumper and the legform impactor model is investigated numerically using LS-DYNA software. The effect of the height of the impact point of bumper assembly to lower extremity injuries is also investigated. In this paper, it is shown that changing the local stiffness of bumper assembly due to the change in the height of the bumper and distribution of stiffness from upper parts of the bumper assembly to lower parts are the most important parameters in the pedestrian’s leg injuries. As lower extremity injuries are related to the lower bumper height, developing special legform impactors for different countries with different average person height seems essential in investigating the effect of people’s height on lower extremity injuries. [Copyright &y& Elsevier]

Abstract: For decades, the importance of highway work zone safety has increased considerably with the continual increase in the number of highway work zones present on highways for repairs and expansion. Rural work zones on two-lane highways are particularly hazardous and cause a significant safety concern due to the disruption of regular traffic flow. In this study, researchers determined motorists’ responses to warning signs in rural, two-lane highway work zones. The researchers divided vehicles into three classes (passenger car, truck, and semitrailer) and compared the mean change in speed of these classes based on three different sign setups: portable changeable message sign (PCMS) OFF, PCMS ON with the message of Slow Down, Drive Safely, and a temporary traffic sign (W20-1, “Road Work Ahead”). Field experiments were conducted on two two-lane work zones with flagger control. Statistical analyses were performed to determine whether there was a significant interaction between motorists’ responses and the sign setups. Data analysis results show that a visible PCMS, either turned on or off, was most effective in reducing truck speeds in rural, two-lane work zones. The temporary traffic sign (W20-1) was more effective in reducing the vehicle speeds of passenger car and semitrailer. Results of this research project will help traffic engineers to better design the two-lane work zone setup and take necessary safety countermeasures to prevent vehicle crashes. [Copyright &y& Elsevier]

Abstract: A study was conducted to investigate the effects of time-gap settings and contents of secondary tasks on a fix-based bus driving simulator on drivers’ performance while reclaiming control from ACC in a car-following scenario of emergency brake by the lead vehicle. Thirty professional bus drivers drove on the simulator with the scenario of highway traffic flow under 12 random time-gap settings: from 0.64s to 2.40s with the interval of 0.16s. As for the effects of secondary tasks, subjects were evenly divided into three conditions: no secondary task interference, simple secondary task, and complex task. The results demonstrated that different safety demarcations of time-gaps on subjective acceptance and driving performance can be found out. The integrated demarcations separated time-gaps into divisions that represented different levels of danger. It revealed that the safer time-gaps for different situations were: longer than 1.60s for none-secondary task distraction and longer than 2.08s for being continuously distracted by secondary tasks. The demand for simple tasks is relatively high, so a larger time-gap is needed for the driver to remain safe. This research has implications for the time-gap selection of ACC and effects of secondary task distraction on buses. A next logical step will focus on determining time-gaps for lead vehicles on curves or slopes, when multiple vehicles are present ahead, and modeling driver behavior and performance with ACC for cars, buses, and other types of vehicles. [Copyright &y& Elsevier]

Abstract: European air traffic control is undergoing changes in organization and technology in order to increase efficiency in air traffic. Change processes can have a negative impact on existing safety cultures, the foundations of safety work, and on safety. This paper reports on an assessment of safety culture at one administrative and two operative units in a Swedish air traffic control setting, using questionnaire packages and interviews, and focuses on 391 questionnaire respondents. The objectives of the study were to obtain baseline data of safety culture aspects and relationships between safety culture and organizational climate before major organizational and technical changes were implemented, and to yield reference data on safety culture aspects in this transport branch. The safety culture aspects were generally perceived and judged to be good by the respondents. Relationships were identified between the organizational climate and the safety culture at the two operative units, where a higher level of Support for ideas and a lower level of Conflicts were positively related to many of the investigated safety culture aspects. The general safety culture in the air traffic control setting was found to be on a somewhat higher average score level than that found in the authors’ previous studies of passenger shipping and airport ground handling. [Copyright &y& Elsevier]

Introduction: A large number of air traffic control occurrences take place without resulting in loss of separation between aircraft. Unfortunately such occurrences are seldom reported and therefore not used for disclosing system weaknesses, such as inappropriate methods and procedures.The ATCC (Air Traffic Control Centre) Malmoe made a trial with local reporting of “learning occurrences”. The trial was ATCO-(Air Traffic Controller) centred. The study objectives were to evaluate if ATCOs would start to report after a defined training and marketing effort, if they could identify system weaknesses, if concrete actions for safety improvement would be taken as a result of the trial and to what extent expert support was necessary.Method and material: The trial period was eight months. The ATCO report would be made on a simple form, available on site. These reports would then be analysed in groups and the marketing and feedback efforts would be co-ordinated by the local flight safety group.Results: 43 reports were filed and analysed during the trial period. The initial motivational training and marketing was considered adequate. During the group discussions, the ATCOs identified system weaknesses within 40 of the reports. The resulting safety improvement actions included: the ATCC unit becoming more active in contacting the pilots and airline companies, the renaming of some waypoints (due to name similarities), the implementation of safer procedures when relieving ATCOs, the training of ATCOs in cockpit flight management systems, and the initiation of a research project primarily concerned with ATCO mental overload.Expert support was required in the beginning to help ATCOs focus on the system rather than on the individual. [Copyright &y& Elsevier]

• This article firstly reviews the urban traffic situation from 1/23/2020 to 3/8/2020 in China. • Between cities, blocking and controlling the traffic are urgent in the early stage of epidemic. • Inside a city, it is urgent to suspend the public transports, block roads, restrict private cars. • We also give suggestions about the long-term planning and improvement methods. • This article offers a valuable reference of urban traffic control now and in the future. Coronavirus disease 2019 (COVID-19) broke out in Wuhan, China. As of March 9, 2020, this epidemic has occurred in 102 countries and caused 3584 deaths with global serious concern. To cope with the outbreak, Chinese governments have strictly controlled urban traffic at all levels, especially in Wuhan. This article firstly reviews the urban traffic situation from January 23, 2020 to March 8, 2020, including safety problems of urban public transportation, traffic control methods, and emergency public transportation planning. Based on this, we present some emergency traffic control measures that are very urgent in the early stage of epidemic. Between cities, we strongly recommend blocking and controlling the flow of traffic in the early stage of epidemic. Inside a city, it is imperative to suspend the public transports, block all roads, restrict private cars, and close bridges and tunnels. Material isolation transfer stations are suggested to be established. A number of public transports should be organized to ensure transport of medical workers, patients, and daily necessities. We also give suggestions about the long-term planning and improvement methods. Considering the great success China has achieved in fighting COVID-19, we believe that this article offers a valuable reference of urban traffic control. [ABSTRACT FROM AUTHOR]