Coordination of horizontal and sag vertical curves on two-lane rural roads: Driving simulator study

Abstract The highway geometric design guidelines for several countries provide suggestions for the coordination of horizontal curves overlapping with sag vertical curves (sag combinations) to avoid combined configurations that produce undesirable optical effects and reduced safety. Such suggestions are derived from studies based on the drawing of the perspective of the road. This drawing method is severely limited with respect to the simulation of the perspective view of the highway to the driver during the dynamic task of driving. Interactive driving simulation methods are deemed to be more efficient for these objectives. This paper reports the results of a study carried out using an interactive driving simulator to evaluate the effects on the driver's speed behavior of different configurations of sag combinations and non-combined curves on a flat grade with the same features as the horizontal curves of the sag combinations (reference curves). The speed behaviors of drivers along the tangent–curve transitions of sag combinations and reference curves were recorded. The speed on the approach tangent, the speed at the midpoint of the horizontal curve and the maximum speed reduction (MSR), the difference between the maximum speed on the last 200 m of the approach tangent and the minimum speed on the first half of the horizontal curve, were analyzed. One-way repeated MANOVA was performed to determine if the driver's speed behavior on the horizontal curves was influenced by different configurations of sag combinations and reference curves. The primary result was that on suggested sag combinations, the driver's speed behavior did not differ in any statistically significant way from that on the reference curves. Whereas the critical sag combinations (configurations that should be avoided) caused high values of maximum speed reduction along the tangent–curve transition, which pointed to the driver's reaction to an incorrect perception of the road alignment. Therefore, this result confirmed the effectiveness of the road design guidelines for the coordination of horizontal curves and sag vertical curves

Effects of safety measures on driver’s speed behavior at pedestrian crossings

This paper reports the results of a multi-factorial experiment that was aimed at the following:(a) analyzing driver’s speed behavior while approaching zebra crossings under different conditions ofvehicle–pedestrian interaction and with respect to several safety measures and (b) comparing safetymeasures and identifying the most effective treatment for zebra crossings. Three safety countermea-sures at pedestrian crossings (curb extensions, parking restrictions and advanced yield markings) andthe condition of no treatment (baseline condition) were designed on a two-lane urban road and imple-mented in an advanced driving simulator. Several conditions of vehicle–pedestrian interaction (in termsof the time left for the vehicle to get to the zebra crossing at the moment the pedestrian starts the cross-ing) were also simulated. Forty-two drivers completed the driving in the simulator. Based on the recordedspeed data, two analyses were performed.The first analysis, which focused on the mean speed profiles, revealed that the driver’s speed behaviorwas affected by conditions of vehicle–pedestrian interaction and was fully consistent with previousfindings in the literature and with the Threat Avoidance Model developed by Fuller.Further analysis was based on variables that were obtained from the speed profiles of drivers (the speedat the beginning of the deceleration phase, the distance from the zebra crossing where the decelerationbegan, the minimum speed value reached during the deceleration, the distance from the pedestriancrossing where the braking phase ended and the average deceleration rate). Multivariate variance anal-ysis (MANOVA) revealed that there was a significant main effect for safety measures and for pedestrianconditions (the presence and absence of a pedestrian). The results identified that the curb extension wasthe countermeasure that induces the most appropriate driver’s speed behavior while approaching thezebra crossing. This conclusion was also confirmed by outcomes of the questionnaire on the counter-measure’s effectiveness. More than 80% of the drivers perceived that the curb extensions were effective,which indicates that when this countermeasure was present, the drivers were more willing to yield andthat the visibility of the pedestrian crossing was better. For this countermeasure, the lowest number ofinteractions in which the drivers did not yield to a pedestrian was also recorded

Survival Model of Drivers' Speed Reduction Time at Bicycle Crossroads: A Driving Simulator Study

The main objective of this study was to assess the effectiveness of several countermeasures at bicycle crossroads on drivers' behavior during the driver–cyclist interaction (a cyclist that crosses the road) by the use of a driving simulator. Three treatments of the cyclist crossroads were investigated: baseline condition (no treatment), raised island, and the colored paved markings. Forty-two participants drove a suburban scenario with several bicycle crossroads having difference configurations and presence/absence of cyclist. Overall, 252 speed profiles were plotted from 150 m before each crossroad of which 23 showed non-yield events: 12 for the baseline condition, 6 for the colored paved markings, and 5 for the raised island. The method of the survival analysis was applied to model the driver speed reduction time (the elapsed time to pass from the initial speed to the minimum speed during the yielding maneuver) with the use of the Weibull distribution. The model identified the average deceleration, the drivers' age, and the countermeasure condition as significant explanatory variables. The survival curves highlighted that for the colored paved markings the driver adopted longer values of the speed reduction times and then a less aggressive driver's braking behavior. Moreover, the outcomes of the questionnaire confirmed that the colored paved markings were considered to be the most effective in terms of driving aid

Driver-pedestrian interaction under legal and illegal pedestrian crossings

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Driver's Braking Behavior

Summary The driver's braking behavior while approaching zebra crossings under different safety measures (curb extensions, parking restrictions, and advance yield markings) and without treatment (baseline condition) was examined. The speed reduction time was the variable used to describe the driver's behavior. Forty-two drivers drove a driving simulator on an urban scenario in which the baseline condition and the safety measures were implemented. The speed reduction time was modeled with a parametric duration model to compare the effects on driver's braking behavior of vehicle dynamic variables and different countermeasures. The parametric accelerated failure time duration model with a Weibull distribution identified that the vehicle dynamic variables and only the countermeasure curb extensions affected, in a statistically significant way, the driver's speed reduction time in response to a pedestrian crossing. This result shows that the driver, because of the improved visibility of the pedestrian allowed by the curb extensions, was able to receive a clear information and better to adapt his approaching speed to yield to the pedestrian, avoiding abrupt maneuvers. This also means a reduction of likelihood of rear-end collision due to less aggressive braking. Copyright © 2016 John Wiley & Sons, Ltd

Benthic foraminifers and siliceous sponge spicules assemblages in the Quaternary rhodolith rich sediments from Pontine Archipelago shelf

The bottom samples (Quaternary in age) of two cores (CS1 and Caro1) collected at 60 and 122 m water depth in the marine area near Ponza Island (Pontine Archipelago, Tyrrhenian Sea) are investigated. In particular, benthic foraminifers and siliceous sponge spicules are considered. The coralline red algae (pralines, boxworks and unattached branches) are abundant in both samples and, particularly, in the CS1 bottom as well as the benthic foraminifers. The siliceous sponge spicules also are very diversified and abundant in the CS1 bottom sample, while in the Caro1 bottom they are rare and fragmented. Benthic foraminiferal assemblage of two samples is dominated by Asterigerinata mamilla and Lobatula lobatula, typical epiphytic species but also able to live on circalittoral detrital seafloors, adapting to an epifaunal lifestyle. Based on these data the bottom of the studied cores represents the upper circalittoral zone, within the present-day depth limit distribution of coralline red algae in the Pontine Archipelago (shallower than 100 m water depth)

driver pedestrian interaction under different road environments

Abstract The objective of the present study was to analyze the drivers' behavior while approaching pedestrian crossings under different driver – pedestrian interaction conditions and to assess the effectiveness of Advanced Driving Assistance Systems (ADASs) for pedestrian detection among several road environments. Three different road environments were implemented in a fixed-base driving simulator: urban road, sub – urban road and rural road. Several driver – pedestrian interactions were implemented in addition to the pedestrian absence condition. The simulated ADAS provided a visual – auditive message. Forty – five participants drove the three road environments scenarios in which three pedestrian crossroads were implemented (pedestrian absence, pedestrian presence with ADAS and pedestrian presence without ADAS). Overall, 369 driver speed profiles were plotted from 150 m before each pedestrian crossroad. ADAS affected the driver behavior in the interaction conditions with Time-To-Zebraarrive 6 s). The effect of ADAS among the road environments was similar for the urban and sub – urban road, resulting in a less abrupt braking maneuver that began in advance compared to that adopted in ADAS absence condition. For the rural road, the main effect was the reaching of a lower minimum speed near the pedestrian crossing and an advanced end of braking maneuver, highlighting the ability of the driver to complete a safer and effective yielding maneuver

Safety assessment of pedestrian-vehicle interaction at signalized intersections: An observational study

Road safety is a crucial aspect of global policies and management. Surrogate Safety Measures (SSMs) have gained attention in the study of pedestrian safety. This study aims to establish an effective SSM methodology to analyze driver-pedestrian interactions. The analysis relies on SSM indicators, without the need for an initial classification of driver-pedestrian interactions into specific interaction patterns. The proposed methodology offers several advantages, including the accurate identification of conflicts through an affordable approach making it easily accessible for public administrations and authorities to assess pedestrian safety at road intersections. A dataset comprising 270 driver-pedestrian interactions, observed at three road intersections in Rome, Italy, was examined. The severity level of each event was assessed through a preliminary classification of each interaction into three patterns: high, low, and none. Subsequently, the severity levels were evaluated using three methods, employing Time-to-Collision (TTC), Post-Encroachment Time (PET), and a combination of TTC and PET. A comparison between the severity levels identified by the two approaches was conducted. The findings reveal that Method 2, utilizing PET, consistently identifies conflicts. Additionally, a binomial logistic regression analysis was performed to identify the variables that influence the likelihood of an interaction escalating into a conflict. The results demonstrate that the probability of conflict increases with the duration of a red signal, particularly for younger pedestrians

An automated method for the ontological representation of security directives

Large documents written in juridical language are difficult to interpret, with long sentences leading to intricate and intertwined relations between the nouns. The present paper frames this problem in the context of recent European security directives. The complexity of their language is here thwarted by automating the extraction of the relevant information, namely of the parts of speech from each clause, through a specific tailoring of Natural Language Processing (NLP) techniques. These contribute, in combination with ontology development principles, to the design of our automated method for the representation of security directives as ontologies. The method is showcased on a practical problem, namely to derive an ontology representing the NIS 2 directive, which is the peak of cybersecurity prescripts at the European level. Although the NLP techniques adopted showed some limitations and had to be complemented by manual analysis, the overall results provide valid support for directive compliance in general and for ontology development in particular

An Ontological Approach to Compliance Verification of the NIS 2 Directive

Cybersecurity, which notoriously concerns both human and technological aspects, is becoming more and more regulated by a number of textual documents spanning several pages, such as the European GDPR Regulation and the NIS Directive. This paper introduces an approach that leverages techniques of semantic representation and reasoning, hence an ontological approach, towards the compliance check with the security measures that textual documents prescribe. We choose the ontology instrument to achieve two fundamental objectives: domain modelling and resource interrogation. The formalisation of entities and relations from the directive, and the consequent improved structuring with respect to sheer prose is dramatically helpful for any organisation through the hard task of compliance verification. The semantic approach is demonstrated with two articles of the new European NIS 2 directive