Sight Distance Research Articles

A novel spatial analysis method to evaluate the safety impact of alternate road lighting

The aim of this paper is to introduce a new method to assess the safety impact of road treatment that influences long sections of road network, such as alternate road lighting, i.e. switching off every other road light at selected roads. The new method used Spatial Traffic Accident Analysis (STAA) – a network-based GIS hotspot analysis method – to identify and map day-time and night-time road traffic accident (RTA) risk levels before and after the implementation of alternate road lighting along a study road. Using the change after treatment in day-time RTA risk levels as a comparison group, and the change after treatment in night-time RTA risk levels as a treatment group, the difference between the treatment change and the comparison change in RTA risk levels was evaluated and mapped along the study road. The spatial distribution of this difference resulted in three different levels of the safety impact of the alternate light treatment at different locations along the study road: no impact, possible impact and highly possible impact. Night-time RTA after the alternate light treatment at road locations with the last two safety impact levels were identified, and their contributory factors were found most likely related to the reduction in night-time sight distance linked to alternate road lighting, and thus validates the safety impact results from the new method.

Internet-of-Things System to Protect Police Officers From Collisions While on Duty on the Roadway

Police officers on duty on the road for traffic stops, vehicle collisions, traffic direction, and so forth, are exposed to the risk of being hit or even killed by a passing vehicle. Very few studies have tried to develop a system that can warn pedestrians or police officers on duty on the road to take proactive evasive action. This study proposes an Internet-of-Things protection system for police officers on duty on the road. The development of the system envisaged involves three essential phases: 1. detection, 2. risk analysis, and 3. warning and communication. This study focused on the risk analysis phase. We applied a fuzzy rule-based algorithm that integrates four input indicators (lateral distance from police officer to traveled lane, magnitude of speeding, stopping sight distance, and direct distance) into a single estimate of the risk of a collision. The study used data from a real-world situation on Highway 416 in Ontario, Canada to demonstrate the application of the proposed model. The results clearly demonstrated that the proposed model could generate risk estimates that could be used to give timely warning of a possible collision risk to police officers at work on a road.

AUDIT KESELAMATAN JALAN RAYA BUKITTINGGI- PAYAKUMBUH

A traffic accident is an event that cannot be avoided, an event where a motorized or non-motorized vehicle comes into contact with each other and causes both material and non-material losses and loss of life. Some of the factors that have the potential to cause accidents are the indiscipline factor in using the vehicle and disobeying existing traffic signs. Jalan Raya Bukittinggi-Payakumnbuh is a class III collector road with a width of ± 9 meters with a sidewalk. Along the audited road are shops and Ford De Kock University. This contributes greatly to attracting the number of people traveling and the high volume of vehicles crossing the Bukittinggi-Payakumbuh highway. Therefore, research was carried out starting from STA 0+100 – STA 1+500, this study aims to analyze road safety by using inspections with the AKJ (Road Safety Audit) checklist table with Y/N answers, such as general condition items, alignment roads, intersections, turning lanes, street lighting and road signs and markings. From the results obtained, the stopping sight distance for an operational speed of 50.07 km/sec in the calculation of the stopping sight distance, the distance of 52.88 meters is still below the design standard and for the ready sight distance of 161.45 meters, the maximum viewing distance of the plan is 350 meters. Based on the AKJ table (road safety audit) for the Bukittinggi-Payakumbuh highway, the highest feasible is from the aspect of signs and road markings of 68.75%, the lowest feasible value is general condition of 50%. The driver factor is the factor causing the highest traffic accidents, namely 26 accidents out of 38 accidents (68.43%), the rest is the vehicle factor, namely 12 accidents out of 38 accidents (31.57%). In order to overcome the problems on the audited roads, it is necessary to repair and complete the signs that are lacking and the maintenance of other complementary facilities in order to reduce traffic accidents. Keywords: Road safety audit, Accident, Stopping visibility, Ready visibility, Bukittinggi-Payakumbuh Highway

Spatial distribution of frequency modulated signals in Uyo, Nigeria

The kernel of this study is to x-ray the extent of radio coverage of two Frequency Modulated (FM) radio stations (AKBC 90.5MHz and Passion FM 94.5MHz), both located in Uyo, Nigeria. Measurement of signal strengths were carried out across 14 locations using a digital spectrum analyzer. A GPS app was used to take measurements of distance, elevation, longitude and latitude. The collected data was analyzed in the form of scattered plot, contour plots, bar charts, graphs and correlation analysis. For AKBC, good reception was received by users at locations N, C, L, and F. For Passion FM, excellent reception was obtained at locations N, F, A and B. For both stations under investigation, location N had the best reception while location E had poor reception. To establish the effects of Line of Sight (LOS) distance on signal strength, correlation values of – 0.84 and - 0.67 were obtained for AKBC and Passion FM. For signal strength against elevation, 0.71 and 0.55 were the correlation values obtained for AKBC and Passion FM. This shows that an increase in distance from the transmitting antenna led to a decrease in reception while an increase in elevation led to an increase in reception. Existing and intending radio stations in Uyo, are advised to increase the height of their transmitter and transmitting power for better reception and coverage.

Survey and Design Consistency Evaluation in Two-Lane Rural Road Segments

The present research proposes a time and cost-effective methodology to survey and perform a design consistency evaluation in two-lane rural road segments. The implementation of the proposed methodology carried out in Central Greece and more particularly along the national road Volos-Karditsa, from the local community Mikrothives up to the entrance of the Volos municipal unit. The road survey methodology, the process of creating the terrain model as well as the cross-check between the designed road with the requirements included in the Greek Road Design Guidelines Manual-Chapter X, are analytically presented. Similar checks are also performed for the sight distance throughout the road segments aiming to enable the rehabilitation of existing rural roads and enhance their safety level. The design of the road was followed by the execution of an experiment with the participation of a motorcycle rider aiming at the recording of his trajectory throughout the road which was then compared with its geometry. The experiment carried out by exploiting an instrumented vehicle and GPS technology. Several conclusions were drawn regarding the encroachment of the centerline and the deviation from the theoretical trajectory in the middle of the travelled way. Subsequently, the proposed methodology provides a reliable and simple solution of surveying and evaluating a 2-lane rural road in safety terms.

Retracted] Study on Driver Gaze Characteristics in Sight Distance Limited Section of Mountain Highway Based on Visual Information

In order to study the gaze behavior characteristics of drivers in mountainous road sections with limited sight distance, the real vehicle test is carried out by using Smart Eye Pro 5.7 noninvasive eye tracker. Combined with the sight distance change rate theory, 6 typical test representative mountainous sections are selected to study the gaze distribution law and gaze duration of drivers in different mountainous sections. The research shows that when the driver drives on the test section with the most unfavorable sight distance of 44 m, 50 m, and 56 m, the fixation characteristics of “from far to near” are significant, and the long fixation duration accounts for a large proportion of the driver. When the driver drives on the section with the most unfavorable sight distance of more than 70 m, i.e., the sight distance change rate of less than 1.33, the fixation characteristics of “from far to near” disappear. The driver’s fixation stability increases, the fixation freedom increases, and the proportion of medium and long fixation duration decreases. The data analysis provides a theoretical basis for drivers to pass safely in mountainous sections.

Effect of Non-urban Two Lane Highway Geometry on Car and Bus Drivers – A Physiological Study

Life is a complex phenomenon, so is the task of driving. Mostly human performance is controlled by sympathetic and parasympathetic systems functioning in human body. It is quite dynamic in response to numerous stimuli the driver acquires from the human-vehicle-environmental ensemble. Geometry is one of the fundamental stimulus for a driver, driving on a non-urban highway, especially when there is minimal interference from other vehicles. Consequently, it is quite natural that drivers adopt higher speeds. His/her mental workload will be based on the input he/she gets from the above system and the rate of reception of input will be more with speed. Any inability to cope with the workload may lead to occurrence of crashes. Hence, it is very important to take into account the influence of geometry on driver workload while designing highways. One way to assess the workload is to capture the physiological responses of a driver like heart rate, galvanic skin resistance and rate of eye blinking, during driving.The study included driving experiments done on 114 horizontal curves of gradient less than 2 percentage, each curve being driven over by 30 car and bus drivers. The effect of geometry on workload of car and bus drivers were further analysed. It was found that driver physical characteristics like, age, driving experience, depth perception, vision acuity and reaction time were not found to significantly influence the workload. But workloads of car and bus drivers are significantly different. Sight distance and width of shoulder affect the workload of car drivers. Sight distance was the significant variable affecting bus driver workload. Workload of a driver is found to increase with increase in visibility as increased visual sensations actuates more physiological responses on a human body.

Traffic Sign Detection Based on Driving Sight Distance in Haze Environment

Traffic Sign Detection Based on Driving Sight Distance in Haze Environment

A New Stopping Sight Distance Model and Fuzzy Reliability Analysis Comparison

Aiming at the research on the stopping sight distance of the highway, on the basis of calculating the stopping sight distance in the current specification, the actual braking process of the car is divided into three stages: the driver’s reaction stage, the braking force rising stage and the continuous braking stage. The calculation model of the complete braking stage is analyzed by MATLAB, and then the calculation model of the stopping sight distance of the ESC system is proposed. Considering the ambiguity of the operating speed, the fuzzy reliability theory is introduced to establish the function of the fuzzy reliability of the stopping sight distance. Using the Gaussian fuzzy number and the center point method, the reliability index and failure probability of the stopping sight distance are obtained, and the safety of the stopping sight distance is evaluated. According to the "Uniform Standard for Reliability Design of Highway Engineering Structures", the traditional reliability calculation method and the fuzzy reliability calculation method are used to calculate the stopping sight distance value that meets the corresponding reliability index of the highway safety level. The calculated value of the system stopping sight distance model is used as a reference, and the reliability index and failure probability of the two reliability calculation methods are calculated. The calculation results show that: compared with the traditional reliability calculation method, the fuzzy reliability calculation method calculates the stopping sight distance value with higher reliability index, lower failure probability and higher calculation accuracy. Implementing the road design based on the stopping sight distance value calculated by the fuzzy reliability theory can improve the road safety.

Analysis of Stopping Sight Distance (SSD) Parameters: A Review Study

Stopping sight distance (SSD) is one of the important elements in geometric highway design, which relies on the two key parameters, i.e., vehicle braking characteristics and drivers’ reaction time. Previous studies have shown higher discrepancies in the coefficients of the SSD parameters, and therefore, making it difficult for practitioners what values to be followed. Therefore, this review study aims to compare deceleration rates and PRT values in different situations that can be applied to geometric highway design. To this end, two electronic databases were searched and relevant articles that reported drivers’ perception reaction time (PRT) or deceleration rates in different situations were identified and included in the review. The obtained results showed that deceleration rates of vehicles ranged from 0.49 m/s2 to 8.76 m/s2 with a total weighted average of 2.82 m/s2. On the other hand, PRT of drivers ranged from 0.48 seconds to 2.01 seconds, with a total weighted average of 1.21 seconds. The key factors that were assessed on deceleration rate of vehicles are surface condition; vehicle type; stimulus; and initial speed. Results of this study suggest that all these factors, except for initial speeds greater than 80 km/h, have a significant effect on deceleration rates of vehicles. The findings of this study could be used as inputs in geometric highway design calculations under different conditions.

Evaluation of Driver Behavior in Response to Stop Sign Beacons

Crashes at rural intersections are frequently a result of failure to yield. As a result, agencies attempt to find countermeasures that encourage drivers to stop and yield appropriately. A number of countermeasures have been utilized to reduce crashes and improve intersection safety. However, some treatments have been shown to have mixed results, while for others only limited information about effectiveness is available. Because even low-cost treatments require some maintenance, it is important for agencies to have good information about the effectiveness of the various treatments before investments are made. Stop sign beacons are one such low-cost measure. This paper discusses results of research which evaluated stop sign beacons. Stop sign beacons were installed at 10 stop-controlled approaches in the US state of Iowa. The beacons were set to activate only when an approaching driver was traveling over a set speed threshold which was set based on whether a driver would be able to stop. Video data were collected before, at 1-month, and at 12-month after installation. Type of stop (i.e., rolling, no-stop), stop location in reference to the stop bar, and location of initial brake application were reduced from the video data. The percentage of drivers who began braking before or after 350 feet were compared. This threshold indicates the point at which drivers would need to engage in hard braking based on approach speed and stopping sight distance. At one month, 6 of the 9 intersections experienced an increase in the percentage of vehicles braking at 350 feet or before. At 12-month, drivers at more than half of the approaches were braking sooner than the before period. Results also indicate stopping behavior improved after installation of the beacons. Most of the approaches (70%) showed an increase in the percentage of drivers who came to a full stop at 1-month compared to the period before installation. At 12-month, 71% of approaches showed an increase in drivers who came to a complete stop. Similar results were found for stopping location. Around 80% of approaches experienced an increase in the percentage of vehicle that stopped at or before the stop bar at the 1-month period after installation and 86% of approaches had an increase at 12-month.

How to determine Safe Speed for negotiating Horizontal Curves with Restricted Sight distance on Two-Lane Highways in India?

How to determine Safe Speed for negotiating Horizontal Curves with Restricted Sight distance on Two-Lane Highways in India?

Older Drivers' Performance at Intersections: An Experimental Study in Italy

Longer life expectancy is leading to an increase in the average age of the European population. In 2018, 20% of the population was over 65 years old. In 2070, 30.3% of the population will be over 65. Older people prefer to walk in their neighborhoods but they rely on cars as their primary mode of transportation, which allows them to maintain their autonomy over long distances. However, age-related physical impairments can have a significant impact on driving skills, including the ability to properly visualize driving scenarios. Numerous studies have shown that older drivers have significant safety problems at standard intersections rather than roundabouts (40% of fatal crashes occur at standard intersections among drivers 70 years and older). In this work, it was decided to study a specific parameter representative of the behavior of all road users when preparing for the typical maneuvers at stop-controlled intersections (crossing, right-turn and left-turn). This parameter is the gap accepted by elderly road users at different stop-controlled intersections and under homogeneous traffic conditions. For this purpose, a research campaign was organized with 37 elderly drivers performing all possible maneuvers at 9 intersections in Italy (Eastern Sicily). The experimentally determined values of the critical gap for left-turn and crossing maneuvers were found to be compatible with those of the main internationally used reference manuals for road design. The value of the critical 50^th percentile gap (G₅₀) for the right-turn maneuver was similar to that for the left-turn maneuver. This is an indication of a very similar level of difficulty for older drivers in performing both turning maneuvers. The results of this study have highlighted the need to take into account the different operational difficulties associated with the possible maneuvers at intersections. The theoretical approaches of the Italian legislation are carried out, based on a criterion that does not distinguish according to the way in which the three maneuvers, which proves to be totally inadequate. This suggests a complete revision of the criteria for checking sight distances at stop-controlled intersections.

Mikrosimulasi Junction Metering dalam Meningkatkan Kinerja Simpang Menggunakan Software Vissim

Sight distance that’s not suitable with the standard, the queue time and the low awareness of vehicle users to give priority to other road users is the reasons for the hampered of traffic movements and reducing the use of intersections. The majority of vehicles for or on minor road use the opponent’s lane because there are no markers, this causes conflict crossing and merging. The researchers conducted study of Junction Metering which consisted of control and sensor settings to improve safety for road users. The method that used for analysis of intersection performance using calculation by software Vissim Full Version and Gap Raff and Hunt. Data collected in this study consisted of four aspects, (1) inventory of intersections; (2) traffic volume; (3) traffic speed; and (4) timelapse. Then alternative junction metering carried out with existing condition. Variable of comparison are level of service, queue length and vehicle delay. The Effectiveness alternative treatment using junction metering can reduce the queue length by 75% and vehicle delay by 17% with the average level of service is A.

Modeling Urban Road Scenarios to Evaluate Intersection Visibility

Road safety is key to sustainable mobility. Rapid technological advances have allowed several road safety-related analyses, previously performed in situ, to be conducted virtually. These virtual analyses benefit understanding of how roads operate and how users perceive them. Additionally, they facilitate the assessment of several parameters that are fundamental to road design and operation. The available sight distance (ASD) is one of these parameters that, if not provided adequately, could alter the proper functioning of roads. This study presents a framework to assess the impact of certain features on visibility. First, the ASD is estimated using a geographic information system (GIS)-based procedure with LiDAR-derived three-dimensional (3D) models. Afterward, obstructions are detected and categorized. If the obstruction cannot be removed, their redesign or relocation is simulated to re-run the analysis. These simulations are performed using 3D city objects, and their results are statistically evaluated, providing evidence as to their effects on visibility. The results proved that the procedure helped achieve the efficient use of roadside space, while including safety concerns. Additionally, this study reflects the need for more inspections on the impact of on-street parking on drivers’ fields of view.

Impact on driver behaviour of guardrails of different height in horizontal-vertical coordinated road scenarios with a limited available sight distance

Drivers consider traffic barriers (e.g., guardrails) a protection system, a hard obstacle and a sight obstruction. Hence, the possibility of using containment level barriers which are higher and superior than the minimum required by current standards should be carefully evaluated. Moreover, research investigations into their impact on driver behaviour should be designed so as to distinguish between the effects associated with each of the three roles cited above.This driving simulation study investigates how drivers adapt their longitudinal and transversal behaviour when negotiating curves with guardrails of different heights on horizontal-vertical coordinated two–lane rural road settings, with consideration given solely to the sight obstruction effect of the guardrails. Fifty-four participants drove four out of the eighteen possible scenarios obtained when the same horizontal alignment is combined with three vertical profiles with three inner roadside treatments (no guardrails, 0.75 m two–wave and 0.95 m three-wave guardrails) and the two driving directions.Research outcomes confirm that guardrail height has a significant impact on lateral and longitudinal behaviour. With the minimum standard, i.e., the minimum height, drivers stay closer to the roadside, while higher guardrails result in drivers increasing their lateral distance. Speeds are influenced by the interaction between the guardrail and other geometric and human factors. Male and female drivers adapt differently to the limitation in the available sight distance caused by the guardrail: males increase their speed, adopting a more aggressive behaviour than females. Important safety implications due to the higher speeds and wider trajectories have to be considered at the design stage.

Coupling impacts of spray and rainfall on road visibility and vehicle speeds: a simulation-based analysis

Impaired visibility resulting from rainfall contributes greatly to the occurrence of traffic accidents. This study presents a numerical simulation approach to analyze the extent to which the coupling of spray and raindrops reduces visibility and, thus, proposes safe speeds against inadequate visibility. The spray–raindrop coupling particles were modeled by considering real highway design parameters and rainfall conditions. The road visibility was estimated through simulating the multiple scattering process of taillights in the spray–rain medium, and the maximum safe speed against inadequate visibility was then derived by comparing the visibility with the required stopping sight distance. Results show that: (i) either a high speed of the front truck or a thick water film results in a significant reduction in road visibility and the maximum safe speed of the ego vehicle, (ii) front vehicle speed plays a more important role in visibility reduction than the water film thickness does.

The Influence Of Traffic Control Devices And Road Geometric Characteristics On Traffic Crushes Of Rular Two Lane Road

Traffic accidents worldwide are among the most alarming phenomena because they cost billions of dollars due to death rates and property damage. In Ethiopia, the accident fatality rate is becoming one of the most serious problems. Specifically, in rural highways where in there are problems with traffic control device enforcement and geometric deficiencies. Gedeo zone faces a similar problem that is considered a hot issue on-road crash. This study focused on the influence of traffic control devices and geometric characteristic related to road crashes. The data collection method was a purposive sampling technique considering both primary and secondary data collection system. Direct field observations were conducted, such as field survey and recording of the existing road geometric elements to figure out which geometric element contributory to traffic crashes. The data collected from the police traffic was categorized by clustering the road into different road segments composed of the same geometric characteristics. The severity of the accident analyzed and identified the hazardous road sections (black spot area). The relationships of accident crash established between the influence of traffic control access devices and geometric elements on the crash reduction at the identified accident-prone areas. Further, the study used ANN modeling through engineering software MATLAB to analyze the weight age of crashes on specified road segments concerning geometric road characteristics. Hence, the gradient carriageway width, super-elevation, cross slope, gradient, sight distance number of the horizontal curve, number of vertical curves, and AADT are the major factors for the occurrence of both fatal and injury at the blackspot segment along the rural highway.

КОМПОНЕНТ ТЕМНОЇ МАТЕРІЇ

A possible component of dark matter is considered. Astronomer began to talk about this matter for a long time, when the speed of movement of galaxies in the clusters was coordinated with classical mechanics. Subsequently, the idea of dark matter became used in the dynamics of stars and lineling phenomena. The observational data of astronomy and astrophysics indicate another path, which leads to the idea of the existence of dark matter, if these data are considered through the prism of the main principles and laws of natural science. On this path, the component of dark matter (DM) appears as an environment in the universe necessary to ensure the life of galaxies. The origin of the dark matter and the functions performed by it are binding to star electromagnetic radiation (SER). Features of the interaction of a two-component system - DM and SER - the basis of all further conclusions. First of all, the outer space is considered filled with subtle forms of matter. It is assumed that DM belongs to them. The presence of two giant material objects distributed over the entire space of the Universe, DM and SER - means their interaction among themselves. First, it follows from dialectic, arguing about the relationship of phenomena in nature. Secondly, from the interpretation of the results of measurements of cosmic microwave radiation obtained by the Arcade system (NASA, 2006). A two-component environment - DM and SER - contains all the baryon matter of the universe, ranging from elementary particles and ending with galactic clusters. Support for "life" of baryon matter is carried out through a number of functions performed by this medium. It is assumed that the star radiation, spreading the space, gives its energy to the dark component. The photons shifted into the microwave region are capable of pairing unaging among themselves in counter courses and small sighting distances. Appearing bosons particles correlate with dark matter. These particles have zero spin or two. Their spectrum of mass turns out to be continuous, the maximum mass of the particle is given. The assumption of energy transmission by a quantum dissemination environment and the microwave hypothesis is consistently explained by many observation results. First of all, it is a red shift in galaxies spectra and the presence of a large cosmic microwave background with its intensity variations at relatively small time intervals. DM particles due to the gravitational interaction return the energy back to its baryonic sources. At the same time, the dark component additionally fills the central supermassive object of the galaxy, which in the quasar phase conducts utilization of star waste with hydrogen regeneration. It is DM that provides large energies allocated by quasars. Given the small part of the star matter, turning into the SER, it is shown that the particles of DM are a medium with a relatively low temperature. It is concluded that DM and SER are a comprehensive dynamic environment in which the baryon matter of the universe lives and develops. Through this two-component "ocean" of matter, all major metabolic processes supporting the "life" of galaxies are carried out.

Accuracy of Interpersonal Distance and Line of Sight Between a Virtual Robot Head and Humans

Accuracy of Interpersonal Distance and Line of Sight Between a Virtual Robot Head and Humans