Vertical Signs Research Articles

ESTUDO DE TRÁFEGO DE VEÍCULOS, INTERVENÇÕES DE SINALIZAÇÕES E URBANISMO TÁTICO NO ENTORNO DO HOSPITAL DA VIDA COMO POLO GERADOR DE VIAGENS

Trip Generating Developments (TGDs) have an influence on traffic in their location and are directly linked to the lack of control in the mobility of vehicles and pedestrians in the location, if their implementation is not properly planned. The objective of this work was to study traffic and conditions around Hospital da Vida (HV), located in the center Dourados-MS, as a Hospital PGV and propose safe mobility to the location. The study was developed with a bibliographical analysis of the topic, data relating to accidents and mobility in the region with local authorities, vehicle and pedestrian counts and on-site visits were also carried out. According to the data obtained, it was shown that HV has a high complexity/cost service, serving 33 municipalities in the region. According to data from counts carried out at the intersection of Toshinobu Katayama Street and Ciro Melo Street in Dourados-MS, a high flow of vehicles was noted, represented mainly by cars, as well as a high flow of pedestrians. In 500 meter radius studied had noticed the highest rate of accidents at the site in 2023, since 2020. Therefore, it was possible to note that the existing signs do not include safe mobility in the study site, with solutions being proposed using tactical urbanism and reinforcement of horizontal and vertical signs, with the aim of increasing safety and helping pedestrians stay and coexist.

Automated Detection of Defects and Vertical Signs on Roadways Using Images Produced by Drivers

Abstract The process of evaluating pavement performance, conventionally performed by visual surveys, tends to be slow and inefficient in countries with extensive networks. The development of object detection algorithms and the popularization of smartphones open the possibility of more automated evaluation processes. This paper proposes the evaluation of the detection of vertical road signs and pavement defects from images produced by drivers using computer vision techniques. A collected set of YouTube videos produced by Brazilian drivers was used to train and validate a convolution neural network model. Results indicated an overall precision of 74.9 %, with observed detection deficiency only for longitudinal cracks and alligator cracking. Potholes, patches, and traffic signs are properly detected (precision between 73 and 95 %, depending on the detected object) for pavement management applications. Provided the diversity of data produced in videos and the overall results obtained in this research, the work herein indicates the possibility of massive citizen participation in the data collection process toward roadway quality.

Dynamic Planning of Vertical Road Signs Maintenance: Operational Methodology

This article is the first of two papers on a topic gaining ground in traffic and transport engineering, namely Dynamic Planning of Vertical Road Signs Maintenance. In particular, this first paper describes the methodologies used in determining the current state, the position, the type, the state of conservation and the efficiency of vertical road signs in the city of Forte dei Marmi (Tuscany, Italy). The ultimate goal is to set up a dynamic GIS-based road vertical signs archive and subsequently develop a forecast model. Such an operational procedure can be seen as a useful tool for setting up a Dynamic Maintenance Plan for all vertical signs along the roads of the municipal area. The methodology followed is the following: once the area of interest has been defined, the retroreflection parameter of the 752 vertical signs present in the area was measured using a retroreflectometer, recording the georeferenced data in a specific GIS database. This hands-on approach allows for both adding and removing a given sign, as well as sorting all monitored signs by age and efficiency in a dynamic operational maintenance view. Hence, the development of the forecasting model has been done, however, for this part reference should be made to the second paper. In the final part of this article, the concluding chapter relating to the creation of a dynamic maintenance plan and the conclusions on the methodology used and on possible ideas for further research developments have been included.

Dynamic Planning of Vertical Road Signs Maintenance: Statistical Evidence

This article is the second of two papers on a topic gaining ground in traffic and transport engineering, namely Dynamic Planning of Vertical Road Signs Maintenance. In particular, this second paper describes the development of the forecasting model and then the analysis of data and the statistical evidence. In detail, starting from the data, a comparison was made between the values measured and those prescribed by the reference standard (UNI EN 12899-1: 2008) according to the category of retroreflective film. Analysing the data macroscopically, it emerged that 75% of the signs met the minimum retroreflective requirements, in compliance with 25% did not respect them. Subsequently, a suitable database was selected for the development of the forecast model, excluding from the sample the vertical signs still under guarantee and proceeding with the correlation between the age of the sign and the retroreflection value found. A statistical analysis of the observed data was then carried out. In detail, the following were carried out: the two-sample t-test, used to verify the statistical significance of the average age difference relating to signs that meet or do not meet the minimum retroreflective requirements; the discriminant analysis with cross-validation, used for the development of the forecasting model; the linear regression, used to evaluate the variation of the retroreflective coefficient as a function of the age of the sign. The summary of the results and the insights for further research developments are made in the conclusions.

Urban Mid-Block Bicycle Crossings: The Effects of Red Colored Pavement and Portal Overhead Bicycle Crossing Sign

This paper aims to investigate the effectiveness of some mid-block bicycle crossing elements by analyzing the drivers’ behavior, when approaching the bicycle crossings in a real road experiments with 18 participants. The eye-tracking instrument has been used to monitor the driver’s visual behavior during the test in an instrumented vehicle with GPS (global positioning system) and an inertial measurement unit (IMU). In particular, the drivers’ gaze was investigated frame by frame while approaching the mid-block bicycle crossings. The results showed that the red colored pavement increased the visibility of the mid-block crossing zone to 65.3% with respect to zebra crossing 59.6%. The drivers’ visual field was also narrowed by the portal overhead bicycle crossing sign and, consequently, drivers reduced their velocity and looked more to the vertical signs by 28%. The drivers’ speed reduction helped drivers to see the mid-block crossing elements from a greater distance with a higher fixation duration.

Driver’s visual perception as a function of age. Using a driving simulator to explore driver’s eye movements in vertical signs

This research aims to evaluate the impact of age on the driver’s attention and perception of road signs, using a driving simulator. The sample focused on drivers aged between 20 and 60 years, since this age range accounts for the largest number of qualified drivers - almost 75% of the total. As drivers gain more experience on the road, the more likely they are to drive safely and therefore, less likely to crash. However, many young and adult drivers become overconfident in their ability to drive and mistakenly believe they are driving safely. The sample studied was analyzed according to the following age groups: Group I, “young” drivers and Group II, “adult” drivers. The collected data included that from the eye tracking system (SmartEye) and questionnaires applied after the experiment. The test scenario replicated a 10 km stretch of a Brazilian highway were the gaze tracking data allowed the measurement of the following variables: observation time, maximum fixation time of signals and the number of signs observed. Both groups had excellent performances in the Simulator’s Post-Drive Questionnaire, with an average correct rate of 94% for Group I and 89% for Group II. Regarding the data provided by eye-tracking system, Group II proved to be more attentive in perceiving speed signs, although in general, they needed to observe the speed sign for longer to be able to perceive it.

The variability of urban safety performance functions for different road elements: an Italian case study

BackgroundUrban 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 methodsThe 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.ResultsCrash 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.ConclusionThe 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.

Detecting Risk Factors of Road Work Zone Crashes from the Information Provided in Police Crash Reports: The Case Study of Portugal

Several studies have shown that European police crash reports provide different detail degrees of work zone crash-related data. In this sense, the present study aims to verify the possibility of identifying significant risk factors involved in the occurrence of road work zone crashes with casualties, based on the official data usually available, through a descriptive, binary logistic, and probit regression statistical analysis. To accomplish the analysis, a total of 2597 police-reports related to 1767 Portuguese work zone crashes that occurred during the 2013–2015 period were considered and binary logistic and probit regression models were estimated by the main type of crash, contributing factor, and driver age group. Fifteen explanatory variables, selected based on the literature review and crash data provided in police crash reports, were considered in the analysis. The results obtained for the estimated coefficients and goodness-of-fit test values were found very similar for both link functions (logit and probit) and it was possible to identify risk factors. The modeling results pointed to excessive speed, disregard for vertical signs, luminosity, intersections, and motorcycle and heavy vehicle involvement as the most significant risk factors. Given the results, it is possible to conclude that binary logistic regression can be used in the statistical analysis of the available police official work zone crash data to identify and get some insight into the risk factors involved in work zone crashes. Data analysis also revealed the need to promote adequate and complete crash report filling by police officers. While police crash reports are not revised and standardized to incorporate more detailed work zone crash information, this approach can be used to support a more efficient road operation decision making and the review of some aspects related to work zone layout design.

Flashing in-curb LEDs and beacons at unsignalized crosswalks and driver’s visual attention to pedestrians during nighttime

Driver’s visual attention (eye movements) and driving behaviour (kinematic data) were assessed when approaching an experimental crosswalk that included flashing white in-curb LED strips, flashing orange beacons, backlit ‘Yield here to pedestrians’ vertical signs, and enhanced lighting when a staged pedestrian attempted to cross. An experimental condition in which all devices were active was compared with a control condition in which only enhanced lighting and backlit vertical signs were active. The results showed a significant increase of motorists’ yielding compliance, distance of first fixation to the pedestrian area, standard deviation for horizontal eye movements in the experimental condition. The introduction of flashing in-curb LED strips and flashing orange beacons proved to be very effective in increasing the night-time safety of the pedestrian crossing. Practitioner summary: The study investigated the effects of flashing in-curb LED strips and beacons on driver’s visual attention (eye movements) and speed when approaching a crosswalk during night-time. The results showed that the combination of these flashing devices significantly increased yielding compliance and the distance of pedestrian detection. Abbreviations: ANOVA: analysis of variance; EU: European Union; HAWK: high intensity activated crosswalk system; LED: light-emitting diode; PHB: pedestrian hybrid beacons; ROI: region of interest; RRFB: rectangular rapid flashing beacons; UK: United Kingdom; US: United States

The safety and conspicuity of pedestrian crossing at roundabouts: The effect of median refuge island and zebra markings

Roundabouts are one of the most used road intersections because, compared to signalized ones, they reduce conflict points between traffic flows and moderate driving speed. Great attention should also be paid to vulnerable road users at roundabouts. According to accident statistics, in fact, accessibility of pedestrians and cyclists is not always ensured.This paper has evaluated the effects on the visibility of pedestrian crossing before and after the displacement of zebra markings, moved before intersections, and the introduction of media refuge islands and “Yield here to pedestrians” vertical signs. The above effects have been assessed by before-after analysis of speed and visual behaviour of drivers approaching the crosswalk.Moreover, the analysis of the drivers’ eye movements has highlighted the most salient elements of the pedestrian crossing. The relation between the drivers’ visual behaviour and the vehicle speed have also been calculated. Results have confirmed that the intervention carried out has increased both visibility and safety of the studied pedestrian crosswalks.Zebra markings and the median refuge island have turned out to be the most glanced elements, respectively seen by 93.75% and 56.25% of the drivers, followed by the “Yield here to pedestrians” vertical sign. The mean distance of first fixation of the crosswalk increased from 21.98 m before the intervention, to 40.69 m after it. The drivers perceived the pedestrian crossings from a longer distance after the intervention, and they continued to glance at the crosswalk while approaching it, enhancing their visual attention.

Traffic Vertical Signposting: Materials Characterization and Structural Numerical Simulation

The existing metallic solutions used for vertical traffic signs are associated with higher costs and environmental issues due to their manufacturing and degradation, when compared with polymeric solutions. Thus, the development of vertical signs considering the injection from polymeric materials in order to overcome problems related with sustainability, maintenance costs, and to achieve higher resistance to corrosion assumes nowadays an important role. The use of eco-friendly and innovative products considering the industrial waste combined with synthetic polymers performing the appropriate mechanical properties, can also be studied to find out new solutions that allow to solve the aforementioned problems. Additionally, these innovative vertical signs can contribute to avoid vandalism events related with theft and graffiti activities. This work presents the prior materials investigation and the structural design of vertical signs that are intended to be produced through polymer injection. Three main steps were considered: i) materials research, ii) materials characterisation through the analysis of polycarbonate resin isolated and in different sets of mixtures with different concentrations through tensile testing and static water contact angle measurements to find the optimal material composition; and iii) structural numerical simulation considering polycarbonate resin and using the current standard EN 12899-1 [1] to compute wind resistance, temporary and permanent deflections. Both experimental and numerical results led to an optimized proposal of the vertical signposting structural design.

Road sign vision and driver behaviour in work zones

The effectiveness of roadwork signs on drivers’ safety is a poorly investigated topic. The present study examined visual fixations of 29 participants to work zone signs, while driving 27 km along rural roads. The drivers’ visual fixations on the work zones signs were recorded with an eye tracking device, synchronized to a GPS recorder that collected kinematic data. The routes crossed 23 roadwork zones, including a total of 69 vertical work zone signs. Visual behaviour to roadwork signs were compared to visual behaviour to permanent vertical signs. The results revealed that drivers glanced at both temporary and permanent signs along the roadwork areas with a similar 40% frequency. In addition, they glanced at single roadwork signs more often and for longer than at multiple-roadwork signs. The main findings of this paper lead to conclude that driver behaviour, investigated by comparing instant speed and visual fixations, is frequently unsafe.

Classification of traffic signal system anomalies for environment tests of autonomous vehicles

Abstract In the future there will be a lot of changes and development concerning autonomous transport that will affect all participants of transport. There are still difficulties in organizing transport, but with the introduction of autonomous vehicles more challenges can be expected. Recognizing and tracking horizontal and vertical signs can cause a difficulties for drivers and, later, for autonomous systems. Environmental conditions, deformity and quality affect the perception of signals. The correct recognition results in safe travelling for everyone on the roads. Traffic signs are designed for people that is why the recognition process is harder for the machines. However, nowadays some developers try to create a traffic sign that autonomous vehicles can use. Computer identification needs further development, as it is necessary to consider cases where traffic signs are deformed or not properly placed. In the following investigation, the advantages and disadvantages of the different perception methods and their possibilities were gathered. A methodology for the classification of horizontal and vertical traffic signs anomalies that may help in designing better testing and validation environments for traffic sign recognition systems in the future was also proposed.

Study of technical parameters of experimental traffic signs — results obtained within the frames of RID 4F research project

This article presents the principles of selection of colours and the thickness of lines during designing of traffic signs, the legal aspects traffic signs must correspond to, test methods used during assessment of both roadway markings and vertical experimental traffic signs, results of studies of those signs and their assessment in the case of possible changes in drivers behaviour.

Design, Modelling, and Implementation of a Fuzzy Controller for an Intelligent Road Signaling System

Crossing points are not always 100% visible for drivers due to different factors (e.g., poor road maintenance, occlusion of vertical signs, and adverse weather conditions). USA estimated in 2015 the number of traffic accidents involving pedestrians and vehicles in 70,000 of whom 5,376 resulted in deceased people. To contribute in this field, this paper presents the design, implementation, and testing of a smart prototype system applied to pedestrian crossings—not regulated by semaphores—which try to reduce the accident rate on roads. The hardware and software system consists of a set of autonomous, intelligent, and wireless low-cost devices that generate a visual warning barrier perceived by drivers from a suitable distance when pedestrians traverse a crosswalk. In this way, drivers can reduce the speed of their vehicles and stop safely. The system’s intelligence is carried out by a fuzzy controller that performs sensory fusion at both low level and high level with various types of sensors from local and neighboring devices. The tests conducted have determined an average success of 94.64% and a precision of 100%, thus corresponding with a very good test according to a ROC analysis. As a result, the system proposed has been patented and extended to international PCT.

Testing the durability and function of road traffic management devices

Traffic management measures (vertical signs and horizontal marking, reflective elements) are used for guiding vehicles optically, indicating road mileage, marking objects in road gauge, marking vehicle and pedestrian safeguards and driver information and warning. This paper presents a synthesis of a literature study and the results of research conducted under stage one of the project LifeRoSE. The requirements for different traffic management measurements are described as well as durability and functionality tests and analysis of factors which influence durability and functionality of these measurements.

The effect of using road safety equipment and systems and determine their role on the suburban roads’ safety performance

In the present communities transportation is a critical component of human life, and one of the main categories in the specification transportation system is the subject of safety. Considering the number of road accidents and deaths caused by it, unfortunately Iran is at the top of countries with the highest number of deaths in traffic accidents, therefore, this has led to that causes of accidents be investigated. To achieve high safety many factors are involve, including appropriate geometric conditions, warning signs and marks, inhibiting rules, safer vehicles, driver familiar with the rules. In this paper, we investigate and evaluate each safety equipment on road performance and with case study on the Tehran-Firouzkouh road determine the existing traffic control equipment situation and by multi-criteria weighting systems AHP decision-making models has been set to evaluate the effects of these factors on safety function. Then according to existing road conditions and the contribution of roads’ different sectors of these systems, a safety priority index number is defined between 0 and 100 and prioritize different levels were expressed in terms of risk. The results have shown that indices median, lighting and panel type and the road’s longitudinal underlining have been identified to have the highest impact on safety. This issue considering sections with complex geometric design with plenty of horizontal curves are very important; also transverse road underlining and warning and regulatory signs in the road have the high weight. But what is noteworthy in this regard is that the total weight of road horizontal symptoms include (underlining and text lines and bumps) is obtained 0.306, and the total weight of the vertical signs (regulatory and warning signs, and traffic lights) 0.181. This issue shows that importance and the effect of horizontal systems on roads is far more than vertical signs of road’s margins. Keywords: Safety; safety equipment and systems; hierarchical analysis

Looking behavior for vertical road signs

Visual fixations at vertical road signs and their recall was tested in 22 participants who drove a route of 8.34km. Gaze was assessed by mobile eye tracking glasses. Recall was assessed at the end of the route by asking each participant to write in a route map all vertical sign that were remembered. The route was the same for all participants and included a total of 75 road signs. The results shown that only 25.06% of vertical signs were looked, and only 6.66% were recalled by the driver at the end of the route. The results are explained in terms of inattentional blindness, automaticity in driving behavior, and the angular offset of the vertical signs to the driver sight line.

Estrategias de búsqueda visual en conductores expertos y noveles durante la visualización de escenas de tráfico

The aim of this study is to analyze the visual search strategies of expert (n=5) and inexperienced drivers (n=5) during a simulated task of driving in laboratory. The ocular movements are recorded with an ASL SE5000 eye tracking system; and the number, time and location of these fixations are analyzed too. The drivers observed a sequence of specific frames of driving, and then they had to respond with a verbal respond after each trial. The results show that the expert and inexperienced group develop different visual search strategies. These differences are the higher time of fixation, independently of location fixation; and even the higher number and time of fixation on relevant stimuli during the driving (vertical signs and vehicles) in the expert group against to other group. Instead, the inexperienced group shows higher number and time on irrelevant stimuli during the driving. There are no differences between groups of drivers on the accuracy of their verbal response, and neither there is any relation between perceptual variables and the accuracy of their responses.

Improved Traffic Signal Detection and Classification via Image Processing Algorithms

An image analysis technique for automatic traffic sign detection and classification is proposed. It makes it possible, after proper training, to detect, recognize and classify vertical road signs from video frames acquired on a moving vehicle equipped with cameras, as well as to identify anomalies with respect to road sign regulations (positioning and visibility).The experimental results show that this technique allows one to correctly detect and classify almost all vertical signs and, mainly in extra-urban environment, it can be considered as highly reliable, apart from being really versatile and user-friendly for road inventory and road maintenance purposes.