A Study of the Minimum Safe Stopping Distance between Vehicles in Terms of Braking Systems, Weather and Pavement Conditions
01 Oct 2012-Indian journal of science and technology (The Indian Society of Education and Environment)-Vol. 5, Iss: 10, pp 3421-3427
TL;DR: In this study, safety distance software has been introduced in order to calculate safe stopping distance based on different conditions and the comparison of the minimum calculated safe distance with the relations delivered in Europe, Iran and British Codes are investigated.
Abstract: One of the most important factors in reducing traffic accidents is to keep safe distance between vehicles. The minimum safe distance depends on many factors such as the drivers' ability to react in accident, the vehicle braking system, the condition of the tires, the corresponding frictional forces provided by the tires, the speed of vehicles and many other factors. The main purpose of this study is to evaluate the above mentioned factors and obtain a relationship between speed and the so called minimum safe distance. In this study "Gim&Nikravesh" and "Sakai" models have been used in order to calculate the braking system force in each tire, using two-wheel equivalent model to calculate the braking force of vehicles and dynamic relations are used to calculate safe stopping time and distance between vehicles. Also the comparison of the minimum calculated safe distance with the relations delivered in Europe, Iran and British Codes are investigated. In this study, safety distance software has been introduced in order to calculate safe stopping distance based on different conditions. This software is designed and compiled by Delphi programming Environment and includes testing different hypothesizes for the back and front tires, calculating details of braking process such as stopping distance and stopping time, separating reflection distance and dynamic stopping distance, simulation of the stop process 3 seconds before confronting danger and finally drawing graphs related in the desired position. There is also a presentation of a recommendable formula in order to calculate the amount of safe distance for the two cases of ordinary braking system and "ABS"(Anti-lock Braking System) which covers the four situations of dry, wet, snowy, and icy positions.
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TL;DR: It was determined that obtained accident risk coefficients could be used to detection of accident risk with minor errors that especially at low speeds up to 60 km/h.
Abstract: In this paper, a new model based on factors of driver, vehicle and environment was developed to determine the ‘safe stopping distance’ of the vehicles, and tested on real road conditions by using equipment placed on the vehicle. The new stopping distance model has been developed based on the stopping distance formula commonly used in the literature. Then, an ‘active driver sight field’ was created considering effect of factors of driver, vehicle and environment. The safe field of view of driver, the safe escape area and safe stopping distance value of vehicle was transferred continuously during driving to the driver through the driver information screen positioned on front console in vehicle cockpit. In addition, a new approach has been developed to evaluate possible accident risks by using relationship between the safe escape area of the vehicle and the safe field of view of the driver. As a result, generalised stopping distance formula was yielded results closer to the actual road results, when expanded by using factors of driver, vehicle and environment. It was determined that obtained accident risk coefficients could be used to detection of accident risk with minor errors that especially at low speeds up to 60 km/h.
10 citations
17 Jun 2014
TL;DR: In this paper, Testler et al. reported that they achieved 80 km/h hizla ve maksimum pedal kuvvetiyle 63oC fren disk sicakliginda tasit 44,9 m'de dururken, 298 oC disk SICAKliginda durma mesafesi %17,4 oraninda artarak 52,71 m olarak olculmustur.
Abstract: Bu deneysel calismada, fren disk sicakliklarindaki artisin tasitin frenleme performansina etkileri arastirilmistir. Bu amacla, frenleme performansinin en onemli gostergesi olan durma mesafesi testleri yapilmistir. Testler, bir hafif ticari tasitta, degisik disk sicakliklari, pedal kuvvetleri, tasit yukleri ve baslangic hizlarinda gerceklestirilmistir. Yapilan fren etkinligi test sonuclari, fren disklerindeki sicaklik artisinin tasitin frenleme mesafesini olumsuz etkiledigini gostermistir. Farkli pedal kuvvetleri, frenleme baslangic hizlari ve tasit yuku degisimlerine gore degerlendirilen sonuclardan, disk sicakligindaki artisin frenleme mesafesini artirdigi gozlenmistir. Tipik bir yol testi sonucu olarak; 80 km/h hizla ve maksimum pedal kuvvetiyle 63oC fren disk sicakliginda tasit 44,9 m’de dururken, 298 oC disk sicakliginda durma mesafesi %17,4 oraninda artarak 52,71 m olarak olculmustur.
1 citations
01 Jan 2018
TL;DR: Two concepts are introduced to determine the possibility of carbon monoxide leakage inside the vehicle cabin space and the other is to determine whether the vehicle has entered into no entry region; this is done using ultrasonic sensor paired with an Arduino and ZigBee.
Abstract: According to the World Health Organization (WHO) report, about 1.25 million people die due to road accident injuries every year. And majority of road crashes are caused by human error. The main objective of this research work is to design a dedicated black box system for automobiles which is used to determine the reason for the accident. Data acquisition is an important process that involves gathering information. By analyzing the various data recorded during road accident, the safety interventions and technology can be implemented to avoid such incident in the future. The black box acts as a data acquisition device, and the acquired data are stored in the Raspberry Pi. During the time of collision, the data acquired are transferred to the traffic control server’s mail id. Sensors play a vital role in the proposed system to identify and analyze the reason for the accident. Sensors list include accelerometer sensor, carbon monoxide sensor, flame sensor. This paper explores the various reasons for accident and the simultaneous catastrophic effects as the result of the collision. It introduces two concepts: One is to determine the possibility of carbon monoxide leakage inside the vehicle cabin space and the other is to determine whether the vehicle has entered into no entry region; this is done using ultrasonic sensor paired with an Arduino and ZigBee.
TL;DR: Wang et al. as discussed by the authors investigated conflicts involving two-wheelers and cars at non-signalized intersections based on trajectory data collected with a YOLOv3-based framework automatically.
Abstract: Unsafe acts at non-signalized intersections have become a primary contributor to traffic accidents and fatalities. Whereas many studies have focused on non-signalized intersections in the past decade, capturing and recording road users’ micro-behavior and risk in the mixed traffic flow remain challenging. A large number of two-wheelers (e.g., bicycles and e-bikes) appear at non-signalized intersections, in which the conflict behaviors are highly unpredictable. In this study, conflicts involving two-wheelers and cars at non-signalized intersections were investigated based on trajectory data collected with a YOLOv3-based framework automatically. A novel conflict identification algorithm was developed to gather and process microscopic trajectory data. To detect conflict behaviors involving two-wheelers and cars, near-crash identification was employed with a post-encroachment time indicator that also contributes to demonstrating the effect of vehicle order on conflict severity from an unprecedented perspective. The proposed framework was applied to a case study at a university campus in Shanghai. To explore the relationship between contributing factors and conflict severity, a significance test and ordered probability models were implemented using 10,304 conflicts collected from video data. The statistical analysis disclosed that conflicts involving e-bikes accounted for the highest proportion, and the order of vehicles (e.g., pre-encroachment vehicle and post-encroachment vehicle) has different effects on conflict severity. The analytical results with risk assessment can contribute to developing intersection-specific countermeasures for traffic safety from the perspectives of education, engineering, and law enforcement. The trajectory-based framework can be adapted to intelligent transportation systems to enhance safety management.
TL;DR: In this paper , a study was conducted to assess and model dynamic load on muscles, physiological variations, and discomfort of the tractor operators arriving from the repeated clutch and brake operations using wearable non-invasive ergonomic transducers and data-run techniques.
Abstract: Dynamic muscular workload assessments of tractor operators are rarely studied or documented, which is critical to improving their performance efficiency and safety. A study was conducted to assess and model dynamic load on muscles, physiological variations, and discomfort of the tractor operators arriving from the repeated clutch and brake operations using wearable non-invasive ergonomic transducers and data-run techniques. Nineteen licensed tractor operators operated three different tractor types of varying power ranges at three operating speeds (4–5 km/h), and on two common operating surfaces (tarmacadam and farm roads). During these operations, ergonomic transducers were utilized to capture the load on foot muscles (gastrocnemius right [GR] and soleus right [SR] for brake operation and gastrocnemius left [GL], and soleus left [SL] for clutch operation) using electromyography (EMG). Forces exerted by the feet during brake and clutch operations were measured using a custom-developed foot transducer. During the process, heart rate (HR) and oxygen consumption rates (OCR) were also measured using HR monitor and K4b2 systems, and energy expenditure rate (EER) was determined using empirical equation. Post-tractor operation cycle, an overall discomfort rating (ODR) for that operation was manually recorded on a 10-point psychophysical scale. EMG-based maximum volumetric contraction (%MVC) measurements revealed higher strain on GR (%MVC = 43%), GL (%MVC = 38%), and SR (%MVC = 41%) muscles which in normal conditions should be below 30%. The clutch and brake actuation forces were recorded in the ranges of 90–312 N and 105–332 N, respectively and were significantly affected by the operating speed, tractor type, and operating surface (p < 0.05). EERs of the operators were measured in the moderate-heavy to heavy ranges (9–24 kJ/min) during the course of trials, suggesting the need to refine existing clutch and brake system designs. Average operator ODR responses indicated 7.8% operations in light, 48.5% in light-moderate, 25.2% in moderate, 10.7% in moderate-high, and 4.9% operations in high discomfort categories. When evaluated for the possibility of minimizing the number of transducers for physical workload assessment, EER showed moderate-high correlations with the EMG signals (rGR = 0.78, rGL = 0.75, rSR = 0.68, rSL = 0.66). Similarly, actuation forces had higher correlations with EMG signals for all the selected muscles (r = 0.70–0.87), suggesting the use of simpler transducers for effective operator workload assessment. As a means to minimize subjectivity in ODR responses, machine learning algorithms, including K-nearest neighbor (KNN), random forest classifier (RFC), and support vector machine (SVM), predicted the ODR using body mass index (BMI), HR, EER, and EMG at high accuracies of 87–97%, with RFC being the most accurate. Such high-throughput and data-run ergonomic evaluations can be instrumental in reconsidering workplace designs and better fits for end-users in terms of agricultural tractors and machinery systems.
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TL;DR: In this paper, the pneumatic tire, axis systems and equations of motion, the control and stability of basic rigid vehicles, suspension characteristics and control and stabilisation of articulated vehicles are discussed.
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01 Dec 1984
TL;DR: In this paper, the stopping sight distance (SSD) model is examined in relation to the following elements: driver eye height, obstacle height, driver perception-response time, vehicle braking distance, and initial vehicle speed.
Abstract: Research was conducted to evaluate existing stopping sight distance criteria in relation to the current vehicle fleet and driver population. The research findings presented in this report are based on field tests of driver and vehicle performance characteristics and capabilities, and a synthesis of current literature and previous research findings. The general stopping sight distance (SSD) model is examined in relation to the following elements: driver eye height, obstacle height, driver perception-response time, vehicle braking distance, and initial vehicle speed. Studies show that for controlled stops from higher speeds by cars with worn tires on slippery roads the required distances are considerably greater than those allowed in the current SSD model. Comments are also made on SSD requirements for trucks under various conditions, studies of rural sites, and sensitivity analyses involving SSD and geometric design.
147 citations
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TL;DR: In this paper, the authors presented an analytical approach for determining tyre dynamic properties as functions of the slip ratio, slip angle, camber angle, and other tyre dynamic parameters, which can be used for the general vehicle simultaneous in braking/traction and steering manoeuvres with varying camber angles are regular or irregular terrains.
Abstract: This is the second paper in a three–part study presenting an analytical approach for determining tyre dynamic properties. In this study analytical formulations are derived for the tyre dynamic properties as functions of the slip ratio, slip angle, camber angle and other tyre dynamic parameters. There formulae can be used for the general vehicle simultaneous in braking/traction and steering manoeuvres with a varying camber angle are regular or irregular terrains. In this paper the lateral force and self–aligning torque due to both slip and camber angles are first studied. The longitudinal, lateral forces and self–aligning torque during braking/traction and steering without any camber angle or with a varying camber angle are also analysed. Also, both the friction eclipse concept and the friction circle concept are investigated.
101 citations
TL;DR: It is confirmed that ABS does have the potential to reduce the number of accidents, but this has not been fully achieved and one reason may be that many drivers have little or no knowledge of ABS.
55 citations