Development of Probabilistic Pedestrian Fatality Model for Characterizing Pedestrian-vehicle Collisions

오철,강연수,Younghan Youn,Atsuhiro Konosu 한국자동차공학회 2008 International journal of automotive technology Vol.9 No.2

Pedestrian-related accidents are considered to be the most serious of traffic accidents due to the associated high fatality rates. In Korea, pedestrian fatalities accounted for approximately 40% of all traffic-related fatalities in 2004. Significant efforts have been made to develop effective countermeasures for pedestrian-vehicle collisions. A basis for devising such countermeasures is to understand the characteristics of pedestrian-vehicle collisions. This study develops a pedestrian fatality model capable of predicting the probability of fatality in pedestrian-vehicle collisions. Binary logistic regression and a probabilistic neural network (PNN) are employed to estimate the probability of pedestrian fatality. Pedestrian age, vehicle type and collision speed are used as independent variables of the fatality model. The models developed herein are valuable tools that can be used to direct safety policies and technologies associated with pedestrian safety.

EVALUATION OF A BRAKE ASSISTANCE SYSTEM (BAS) USING AN INJURY SEVERITY PREDICTION MODEL FOR PEDESTRIANS

오철,강연수,윤영한 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.5

Through the years, traffic engineers and researchers have developed a variety of countermeasures to enhance pedestrian safety. Pedestrian-vehicle collisions are regarded as the most serious type of accident since they incur high fatality rates. A fundamental concept in developing effective countermeasures is to analyze pedestrian-vehicle collisions scientifically, which can identify the causes of accidents and accident severity. The objective of this study was to investigate the pedestrian safety benefit of the brake assistance system (BAS) and a functional requirement associated with BAS, namely the time needed to safely detect a pedestrian ahead. An injury severity prediction model for pedestrians was developed to systematically evaluate the BAS in this study. Ordered multinomial logistic regression analysis was used to establish a statistical model capable of predicting pedestrian injury severity. In addition to vehicle characteristics, collision speed and pedestrian characteristics were used as independent predictor variables. The outcomes of this study would be useful in directing the development of safety policies and technologies associated with pedestrian safety. Through the years, traffic engineers and researchers have developed a variety of countermeasures to enhance pedestrian safety. Pedestrian-vehicle collisions are regarded as the most serious type of accident since they incur high fatality rates. A fundamental concept in developing effective countermeasures is to analyze pedestrian-vehicle collisions scientifically, which can identify the causes of accidents and accident severity. The objective of this study was to investigate the pedestrian safety benefit of the brake assistance system (BAS) and a functional requirement associated with BAS, namely the time needed to safely detect a pedestrian ahead. An injury severity prediction model for pedestrians was developed to systematically evaluate the BAS in this study. Ordered multinomial logistic regression analysis was used to establish a statistical model capable of predicting pedestrian injury severity. In addition to vehicle characteristics, collision speed and pedestrian characteristics were used as independent predictor variables. The outcomes of this study would be useful in directing the development of safety policies and technologies associated with pedestrian safety.

Pedestrian-Vehicle Collision Vulnerability in Senior Citizens’ Walking Environment: An Area-Level Investigation of Seoul, South Korea

김현수,오승훈,최열 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

The safety of senior pedestrians is a major challenge in cities, particularly in a rapidly aging society. This study takes place in Seoul, South Korea, where pedestrian safety in highly urban environments poses a major threat. Using several big databases, the study investigated 142 frequent collision areas where 583 pedestrian–vehicle collisions involving seniors were reported in 2017. Using Poisson and negative binomial regression, we modeled the relationship between collisions and three sets of area-specific environmental characteristics: Land-use; transportation and pedestrian infrastructures; and population characteristics. Two different scales of walking environment of senior citizens were investigated: the frequent collision areas (200-meter radius), and their pedestrian sheds (1-kilometer radius). The study further dissectedcommercial areas and roadways into types of destinations and roadway classifications, and found that the neighborhoods with a higher number of medical institutes and a denser network of minor roads were associated with higher risk of collisions. The study found that senior pedestrians were more vulnerable in low-income neighborhoods, especially in the areas with larger resident and floating population of seniors. The findings from the study provided some meaningful information on the risk of collision, and policy implications to improve the safety of senior pedestrians.

CHARACTERISTICS OF COLLISION DAMAGE MITIGATION BRAKING SYSTEM FOR PEDESTRIAN PROTECTI

S. OIKAWA,Y. MATSUI,T. SAKURAI 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.7

The vehicle travel velocity at pedestrian contact is considered to be an important parameter that affects thecrash outcome. To reduce vehicle/pedestrian impact velocity, a collision damage mitigation braking system (CDMBS) usinga sensor for pedestrian protection could be an effective countermeasure. The first purpose of this study is to clarify the relationbetween vehicle travel velocity and pedestrian injury severity due to differences in pedestrians’ ages in actual traffic accidents. The accident analyses were performed using vehicle-pedestrian accident data in 2009 from the database of the Institute forTraffic Accident Research and Data Analysis (ITARDA) in Japan. The result revealed that the fatality risk became higher withthe increase in vehicle travel velocity. The second purpose of this study is to determine the safety performance of productionvehicles equipped with the CDMBS for pedestrian protection. It was found that the CDMBS was highly effective in reducingthe impact velocity from 50 km/h (vehicle travel velocity) to below 17 km/h, that could result in a significant decrease infatality risk to be 2% or less. Additionally, the authors investigated a detectable zone with respect to a pedestrian’s positionin relation to the vehicle. It was shown that the detectable zones for production vehicles tested were limited to be inside thevehicle front width

COLLISION AVOIDANCE OF LOW SPEED AUTONOMOUS SHUTTLES WITH PEDESTRIANS

Sukru Yaren Gelbal,Bilin Aksun-Guvenc,Levent Guvenc 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.4

This paper is on a pedestrian collision avoidance system for low speed autonomous shuttles based on Vehicle-to-Pedestrian (V2P) communication. When pedestrians cannot be detected using line-of-sight sensors like camera, radar and LIDAR, V2P communication with the Dedicated Short Range Communication (DSRC) enabled pedestrian smartphone is used to detect and localize them through the in-vehicle DSRC radio used for Vehicle-to-Everything (V2X) communication. The vehicle, then, either stops or, if possible, goes around the pedestrian in a socially acceptable manner using the elastic band method for locally modifying the vehicle trajectory in real time. The elastic band method of collision avoidance is modified for fast real time execution in this paper. Along with model-in-the-loop simulations, a hardware-in-the-loop simulator using an automated driving vehicle model in the high fidelity vehicle dynamics simulation program Carsim Real Time with Sensors and Traffic with two DSRC modems emulating the vehicle and pedestrian communications is introduced and used in this paper as a prerequisite to real world experiments. Both stationary and moving pedestrians are considered in the model and hardware-in-the-loop simulations. Two real world experiments are also presented to demonstrate the V2P based avoidance of crashes between low speed autonomous shuttles and pedestrians.

Analysis of Pedestrian Collision Risk using Fuzzy Inference Model

Joko Hariyono,Laksono Kurnianggoro,Wahyono,Kang-Hyun Jo 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

The aim of this work is to improve driver awareness by proposing a collision risk analysis method. Pedestrian in the scene is observed by sequential frames from monocular camera mounted on the car. Positional information of object is extracted by projecting the centroid of bounding box on the ground plane. Four elements of collision criteria are constructed which are pedestrian walking direction, its velocity, car speed and relative distance of pedestrian. The analysis of collision risk is performed using fuzzy inference method that is used for calculating the degree of risk. Furthermore, localization of pedestrian is performed according to its risk score. The pedestrian with low collision score is labeled as low risk (green), pedestrian which is increasing its collision score is considered as medium risk (yellow) and pedestrian with high collision score is labelled as high risk (red). A quantitative analysis is performed by measuring effectiveness of this approach. The performance evaluation shows our proposed method achieved average accuracy 87.5% and it significantly outperforms human perception with more than 25% improvement.

주거지역의 보행안전 영향요인과 도시설계적 시사점 - 고령 보행자를 대상으로

이새롬(Lee, Sae Rom),양희진(Yang, Hee Jin) 한국도시설계학회 2021 도시설계 : 한국도시설계학회지 Vol.22 No.4

본 연구는 고령자의 보행안전에 관한 논의가 부족했다는 문제의식 하에 양적·질적 혼합연구방법을 통해서 주거지역의 안전한 보행환경 조성을 위한 도시설계적 시사점을 제시하는 것을 목적으로 하였다. 이를 위해 먼저 서울의 주거지역을 대상으로 교통환경, 보행환경, 근린환경 요소가 고령자 보행사고에 미치는 영향을 평가하는 종합적인 분석틀을 제시하였다. 로지스틱 회귀분석 결과, 교차로 및 대중교통시설 밀도와 같은 교통환경, 보차혼용 비율과 같은 보행환경을 통제하더라도 고층주택지 비율, 평균 필지규모와 같은 근린환경 특성에 따라 고령자 보행안전에 유의미한 차이가 확인되었다. 또한 현장관찰 및 고령자 인터뷰에 따르면 저층 주거지역은 보행 공간의 연속성이 상대적으로 부족하고 보행혼용 도로의 비중이 높으며, 주거공간과 근린시설의 연계성이 낮아 고령자의 보행위험이 높아지는 것을 확인하였다. 이러한 분석 결과로부터 본 연구는 주거지역에서 고령자의 보행안전을 제고하기 위해서는 주차장, 공원 등의 생활인프라 공급과 보행환경을 함께 개선하는 포괄적 주거개선 사업이 필요함을 제언하였다. With the lack of discussion around older pedestrian safety in residential areas, this study carries out both quantitative and qualitative analyses with a mixed-method approach to providing implications for urban design. Taking a case of residential areas in Seoul, this study comprehensively evaluates the impacts of traffic, pedestrian, and neighborhood environmental factors on older pedestrian accidents. Our research confirms that, even after controlling for traffic and pedestrian environmental factors, neighborhood environment characteristics (i.e. lot sizes and housing type) are significantly associated with older pedestrians’ safety. According to field observations and interviews with older adults, the risk of pedestrian accidents in low-rise residential areas increases due to a relatively lack of continuity of pedestrian spaces, inadequate separation of pedestrian spaces and vehicle movement, as well as unintegrated arrangement with neighborhood facilities. This study suggests that it is necessary to improve older pedestrians’ safety through a comprehensive planning strategy in residential areas, which not only provides living infrastructure (i.e. parking spaces and parks) but also enhances pedestrian environments.

안전한 통학로 조성을 위한 보행자-차량간 교통사고와 학교주변의 물리적 환경과의 연관성 연구

박승훈(Park, Seung-Hoon) 대한건축학회 2014 대한건축학회논문집 Vol.30 No.8

The purpose of this study is to explore environmental correlates of pedestrian-vehicle collisions within walkable distance from neighborhood schools in order to promote safe walking environment around schools. For this research, the total number of pedestrian-vehicle collisions occurred around each neighborhood school for 2000 through 2004 is measured as an indicator of the safety level of walking environment around schools. A negative binomial regression model is employed for spatial quantitative analysis. The result of spatial analysis indicates that sidewalk density, traffic signal density, cul-de-sac density, the number of fast-food restaurants, the number of parking lots, and the number of residential units are positively associated with pedestrian-vehicle collisions. However, it is found that the number of play grounds, the percentage of single-family housing areas, the percentage of mixed use areas, and average property value have negative association with pedestrian-vehicle collisions. These key findings of this research contribute to better understanding of the gaps in the current knowledge, for safe routes to school, regarding safe walking environment around neighborhood schools by providing new substantive knowledge regarding the significant effects of the physical environment on pedestrian-vehicle collisions.

모바일폰 문자 메시지가 동적 · 정적 보행자 충돌회피전략에 미치는 영향

( Yeon-jong Lee ),( Joo-nyeon Kim ) 한국운동역학회 2021 한국운동역학회지 Vol.31 No.1

Objective: The purpose of this study was to investigate the effect of mobile phone text messaging on the collision avoidance strategy for an approaching and stationary pedestrian. Method: Eighteen healthy young adults participated in this study. Each participant was asked to perform a task to walking with/without mobile phone text messaging and a task to avoid collisions with another pedestrian who was approaching or stationary during walking. Results: When text messaging with avoidance collision, it showed an early onset time, a larger mediolateral COM trajectory, trunk rotation angle and trunk rotation velocity (p<.05). Also, compared to an approaching pedestrian, when avoiding collision with a stationary pedestrian, it showed a later onset time, a lager avoidance displacement, mediolateral COM trajectory, trunk rotation angle (p<.05). Conclusion: Results suggest that mobile phone text messaging while collision avoidance leads to delay the perception stage and alters the adaptation stage. Consequently, pedestrian executed in an exaggerated avoidance action to create a greater safety margin when attending to mobile phone test messages while avoiding another pedestrian.

INFLUENCE OF THE GEOMETRIC PARAMETERS OF THE VEHICLE FRONTAL PROFILE ON THE PEDESTRIAN’S HEAD ACCELERATIONS IN CASE OF ACCIDENTS

Bogdan Tolea,Alexandru Ionut Radu,Horia Beles,Csaba Antonya 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.1

The goal of this paper is to determine how the geometry of the vehicle’s frontal profile is influencing the pedestrian’s head accelerations (linear and angular) in car-to-pedestrian accidents. In order to achieve this goal, a virtual multibody dummy of the pedestrian was developed and multiple simulations of accidents were performed using vehicles with different frontal profile geometry, from different classes. The type of accidents considered is characteristic for urban areas and occur at relatively low speed (around 30 km/h) when an adult pedestrian is struck from the rear and the head acceleration variation are the measurement of the accident severity. In the accident simulation 3D meshes were applied on the geometry of the vehicles, in order to define the contact surface with the virtual dummy, similar with real vehicles. The validation of the virtual pedestrian dummy was made by performing two crash-tests with a real dummy, using the same conditions as in the simulations. The measured accelerations in the tests were the linear and angular accelerations of the head during the impact, and these were compared with the ones from the simulations. After validating the virtual model of the car-to-pedestrian accident, we were able to perform multiple simulations with different vehicle shapes. These simulations are revealing how the geometric parameters of the vehicle’s frontal profile are influencing the head acceleration. This paper highlights the main geometric parameters of the frontal profile design that influence the head injury severity and the way that the vehicles can be improved by modifying these parameters. The paper presents an approach to determine the “friendliness” of the vehicle’s frontal profile in the car-to-pedestrian collision.